./kernelbenchhardv3runsopencode · ?
opencode / ? session: ses_22f39cef6ffeCdrdIuvEeAGYZk cwd: ?
harness
opencode
model
?
turns
200
tools called
102
events
301
input toks
142,997
output toks
64,607
cache hit
7,763,936
solution.py
final answer
benchmark.log
check.log
result.json
"""Fused W4A16 GEMM — CUDA C++ via load_inline, AWQ/GPTQ-style asymmetric int4.

Dequantizes on-the-fly: (w_q[k,n] - zeros[g,n]) * scales[g,n] with group=128
along K. Two int4 weights are packed per uint8 byte (low nibble=even, high=odd).
"""
from __future__ import annotations

import torch
import torch.nn as nn
import torch.utils.cpp_extension

OP_TYPE = "gemm_w4a16"
SUPPORTED_PRECISIONS = ["int4_bf16"]
HARDWARE_REQUIRED = ["RTX_PRO_6000", "H100", "B200"]

GROUP_SIZE = 128


def _pack_int4(w_q: torch.Tensor) -> torch.Tensor:
    K, N = w_q.shape
    assert K % 2 == 0
    lo = w_q[0::2].to(torch.uint8) & 0xF
    hi = w_q[1::2].to(torch.uint8) & 0xF
    return (lo | (hi << 4)).contiguous()


def _unpack_int4(w_packed: torch.Tensor, K: int) -> torch.Tensor:
    Kh, N = w_packed.shape
    assert Kh * 2 == K
    out = torch.empty((K, N), dtype=torch.uint8, device=w_packed.device)
    out[0::2] = w_packed & 0xF
    out[1::2] = (w_packed >> 4) & 0xF
    return out


cuda_source = r"""
#include <torch/extension.h>
#include <cuda_bf16.h>

#define GROUP_SIZE 128
#define THREADS_N 256

__global__
void w4a16_kernel(
    const __nv_bfloat16* __restrict__ x,
    const unsigned char* __restrict__ w_q,
    const __nv_bfloat16* __restrict__ scales,
    const __nv_bfloat16* __restrict__ zeros,
    __nv_bfloat16* __restrict__ y,
    int M, int N, int K, int n_groups
) {
    int n = blockIdx.x * THREADS_N + threadIdx.x;
    int m = blockIdx.y;

    if (n >= N || m >= M) return;

    float acc = 0.0f;

    const __nv_bfloat16* x_row = x + m * K;

    for (int g = 0; g < n_groups; ++g) {
        int k_base = g * GROUP_SIZE;

        float scale = __bfloat162float(scales[g * N + n]);
        float zero = __bfloat162float(zeros[g * N + n]);

        int w_row_base = k_base >> 1;

        unsigned char wp0 = w_q[w_row_base * N + n];
        unsigned char w0_e = wp0 & 0xF;
        unsigned char w0_o = (wp0 >> 4) & 0xF;
        float x0_e = __bfloat162float(x_row[k_base]);
        float x0_o = __bfloat162float(x_row[k_base + 1]);
        acc += x0_e * (((float)w0_e - zero) * scale);
        acc += x0_o * (((float)w0_o - zero) * scale);

        unsigned char wp1 = w_q[(w_row_base + 1) * N + n];
        unsigned char w1_e = wp1 & 0xF;
        unsigned char w1_o = (wp1 >> 4) & 0xF;
        float x1_e = __bfloat162float(x_row[k_base + 2]);
        float x1_o = __bfloat162float(x_row[k_base + 3]);
        acc += x1_e * (((float)w1_e - zero) * scale);
        acc += x1_o * (((float)w1_o - zero) * scale);

        unsigned char wp2 = w_q[(w_row_base + 2) * N + n];
        unsigned char w2_e = wp2 & 0xF;
        unsigned char w2_o = (wp2 >> 4) & 0xF;
        float x2_e = __bfloat162float(x_row[k_base + 4]);
        float x2_o = __bfloat162float(x_row[k_base + 5]);
        acc += x2_e * (((float)w2_e - zero) * scale);
        acc += x2_o * (((float)w2_o - zero) * scale);

        unsigned char wp3 = w_q[(w_row_base + 3) * N + n];
        unsigned char w3_e = wp3 & 0xF;
        unsigned char w3_o = (wp3 >> 4) & 0xF;
        float x3_e = __bfloat162float(x_row[k_base + 6]);
        float x3_o = __bfloat162float(x_row[k_base + 7]);
        acc += x3_e * (((float)w3_e - zero) * scale);
        acc += x3_o * (((float)w3_o - zero) * scale);

        unsigned char wp4 = w_q[(w_row_base + 4) * N + n];
        unsigned char w4_e = wp4 & 0xF;
        unsigned char w4_o = (wp4 >> 4) & 0xF;
        float x4_e = __bfloat162float(x_row[k_base + 8]);
        float x4_o = __bfloat162float(x_row[k_base + 9]);
        acc += x4_e * (((float)w4_e - zero) * scale);
        acc += x4_o * (((float)w4_o - zero) * scale);

        unsigned char wp5 = w_q[(w_row_base + 5) * N + n];
        unsigned char w5_e = wp5 & 0xF;
        unsigned char w5_o = (wp5 >> 4) & 0xF;
        float x5_e = __bfloat162float(x_row[k_base + 10]);
        float x5_o = __bfloat162float(x_row[k_base + 11]);
        acc += x5_e * (((float)w5_e - zero) * scale);
        acc += x5_o * (((float)w5_o - zero) * scale);

        unsigned char wp6 = w_q[(w_row_base + 6) * N + n];
        unsigned char w6_e = wp6 & 0xF;
        unsigned char w6_o = (wp6 >> 4) & 0xF;
        float x6_e = __bfloat162float(x_row[k_base + 12]);
        float x6_o = __bfloat162float(x_row[k_base + 13]);
        acc += x6_e * (((float)w6_e - zero) * scale);
        acc += x6_o * (((float)w6_o - zero) * scale);

        unsigned char wp7 = w_q[(w_row_base + 7) * N + n];
        unsigned char w7_e = wp7 & 0xF;
        unsigned char w7_o = (wp7 >> 4) & 0xF;
        float x7_e = __bfloat162float(x_row[k_base + 14]);
        float x7_o = __bfloat162float(x_row[k_base + 15]);
        acc += x7_e * (((float)w7_e - zero) * scale);
        acc += x7_o * (((float)w7_o - zero) * scale);

        unsigned char wp8 = w_q[(w_row_base + 8) * N + n];
        unsigned char w8_e = wp8 & 0xF;
        unsigned char w8_o = (wp8 >> 4) & 0xF;
        float x8_e = __bfloat162float(x_row[k_base + 16]);
        float x8_o = __bfloat162float(x_row[k_base + 17]);
        acc += x8_e * (((float)w8_e - zero) * scale);
        acc += x8_o * (((float)w8_o - zero) * scale);

        unsigned char wp9 = w_q[(w_row_base + 9) * N + n];
        unsigned char w9_e = wp9 & 0xF;
        unsigned char w9_o = (wp9 >> 4) & 0xF;
        float x9_e = __bfloat162float(x_row[k_base + 18]);
        float x9_o = __bfloat162float(x_row[k_base + 19]);
        acc += x9_e * (((float)w9_e - zero) * scale);
        acc += x9_o * (((float)w9_o - zero) * scale);

        unsigned char wp10 = w_q[(w_row_base + 10) * N + n];
        unsigned char w10_e = wp10 & 0xF;
        unsigned char w10_o = (wp10 >> 4) & 0xF;
        float x10_e = __bfloat162float(x_row[k_base + 20]);
        float x10_o = __bfloat162float(x_row[k_base + 21]);
        acc += x10_e * (((float)w10_e - zero) * scale);
        acc += x10_o * (((float)w10_o - zero) * scale);

        unsigned char wp11 = w_q[(w_row_base + 11) * N + n];
        unsigned char w11_e = wp11 & 0xF;
        unsigned char w11_o = (wp11 >> 4) & 0xF;
        float x11_e = __bfloat162float(x_row[k_base + 22]);
        float x11_o = __bfloat162float(x_row[k_base + 23]);
        acc += x11_e * (((float)w11_e - zero) * scale);
        acc += x11_o * (((float)w11_o - zero) * scale);

        unsigned char wp12 = w_q[(w_row_base + 12) * N + n];
        unsigned char w12_e = wp12 & 0xF;
        unsigned char w12_o = (wp12 >> 4) & 0xF;
        float x12_e = __bfloat162float(x_row[k_base + 24]);
        float x12_o = __bfloat162float(x_row[k_base + 25]);
        acc += x12_e * (((float)w12_e - zero) * scale);
        acc += x12_o * (((float)w12_o - zero) * scale);

        unsigned char wp13 = w_q[(w_row_base + 13) * N + n];
        unsigned char w13_e = wp13 & 0xF;
        unsigned char w13_o = (wp13 >> 4) & 0xF;
        float x13_e = __bfloat162float(x_row[k_base + 26]);
        float x13_o = __bfloat162float(x_row[k_base + 27]);
        acc += x13_e * (((float)w13_e - zero) * scale);
        acc += x13_o * (((float)w13_o - zero) * scale);

        unsigned char wp14 = w_q[(w_row_base + 14) * N + n];
        unsigned char w14_e = wp14 & 0xF;
        unsigned char w14_o = (wp14 >> 4) & 0xF;
        float x14_e = __bfloat162float(x_row[k_base + 28]);
        float x14_o = __bfloat162float(x_row[k_base + 29]);
        acc += x14_e * (((float)w14_e - zero) * scale);
        acc += x14_o * (((float)w14_o - zero) * scale);

        unsigned char wp15 = w_q[(w_row_base + 15) * N + n];
        unsigned char w15_e = wp15 & 0xF;
        unsigned char w15_o = (wp15 >> 4) & 0xF;
        float x15_e = __bfloat162float(x_row[k_base + 30]);
        float x15_o = __bfloat162float(x_row[k_base + 31]);
        acc += x15_e * (((float)w15_e - zero) * scale);
        acc += x15_o * (((float)w15_o - zero) * scale);

        unsigned char wp16 = w_q[(w_row_base + 16) * N + n];
        unsigned char w16_e = wp16 & 0xF;
        unsigned char w16_o = (wp16 >> 4) & 0xF;
        float x16_e = __bfloat162float(x_row[k_base + 32]);
        float x16_o = __bfloat162float(x_row[k_base + 33]);
        acc += x16_e * (((float)w16_e - zero) * scale);
        acc += x16_o * (((float)w16_o - zero) * scale);

        unsigned char wp17 = w_q[(w_row_base + 17) * N + n];
        unsigned char w17_e = wp17 & 0xF;
        unsigned char w17_o = (wp17 >> 4) & 0xF;
        float x17_e = __bfloat162float(x_row[k_base + 34]);
        float x17_o = __bfloat162float(x_row[k_base + 35]);
        acc += x17_e * (((float)w17_e - zero) * scale);
        acc += x17_o * (((float)w17_o - zero) * scale);

        unsigned char wp18 = w_q[(w_row_base + 18) * N + n];
        unsigned char w18_e = wp18 & 0xF;
        unsigned char w18_o = (wp18 >> 4) & 0xF;
        float x18_e = __bfloat162float(x_row[k_base + 36]);
        float x18_o = __bfloat162float(x_row[k_base + 37]);
        acc += x18_e * (((float)w18_e - zero) * scale);
        acc += x18_o * (((float)w18_o - zero) * scale);

        unsigned char wp19 = w_q[(w_row_base + 19) * N + n];
        unsigned char w19_e = wp19 & 0xF;
        unsigned char w19_o = (wp19 >> 4) & 0xF;
        float x19_e = __bfloat162float(x_row[k_base + 38]);
        float x19_o = __bfloat162float(x_row[k_base + 39]);
        acc += x19_e * (((float)w19_e - zero) * scale);
        acc += x19_o * (((float)w19_o - zero) * scale);

        unsigned char wp20 = w_q[(w_row_base + 20) * N + n];
        unsigned char w20_e = wp20 & 0xF;
        unsigned char w20_o = (wp20 >> 4) & 0xF;
        float x20_e = __bfloat162float(x_row[k_base + 40]);
        float x20_o = __bfloat162float(x_row[k_base + 41]);
        acc += x20_e * (((float)w20_e - zero) * scale);
        acc += x20_o * (((float)w20_o - zero) * scale);

        unsigned char wp21 = w_q[(w_row_base + 21) * N + n];
        unsigned char w21_e = wp21 & 0xF;
        unsigned char w21_o = (wp21 >> 4) & 0xF;
        float x21_e = __bfloat162float(x_row[k_base + 42]);
        float x21_o = __bfloat162float(x_row[k_base + 43]);
        acc += x21_e * (((float)w21_e - zero) * scale);
        acc += x21_o * (((float)w21_o - zero) * scale);

        unsigned char wp22 = w_q[(w_row_base + 22) * N + n];
        unsigned char w22_e = wp22 & 0xF;
        unsigned char w22_o = (wp22 >> 4) & 0xF;
        float x22_e = __bfloat162float(x_row[k_base + 44]);
        float x22_o = __bfloat162float(x_row[k_base + 45]);
        acc += x22_e * (((float)w22_e - zero) * scale);
        acc += x22_o * (((float)w22_o - zero) * scale);

        unsigned char wp23 = w_q[(w_row_base + 23) * N + n];
        unsigned char w23_e = wp23 & 0xF;
        unsigned char w23_o = (wp23 >> 4) & 0xF;
        float x23_e = __bfloat162float(x_row[k_base + 46]);
        float x23_o = __bfloat162float(x_row[k_base + 47]);
        acc += x23_e * (((float)w23_e - zero) * scale);
        acc += x23_o * (((float)w23_o - zero) * scale);

        unsigned char wp24 = w_q[(w_row_base + 24) * N + n];
        unsigned char w24_e = wp24 & 0xF;
        unsigned char w24_o = (wp24 >> 4) & 0xF;
        float x24_e = __bfloat162float(x_row[k_base + 48]);
        float x24_o = __bfloat162float(x_row[k_base + 49]);
        acc += x24_e * (((float)w24_e - zero) * scale);
        acc += x24_o * (((float)w24_o - zero) * scale);

        unsigned char wp25 = w_q[(w_row_base + 25) * N + n];
        unsigned char w25_e = wp25 & 0xF;
        unsigned char w25_o = (wp25 >> 4) & 0xF;
        float x25_e = __bfloat162float(x_row[k_base + 50]);
        float x25_o = __bfloat162float(x_row[k_base + 51]);
        acc += x25_e * (((float)w25_e - zero) * scale);
        acc += x25_o * (((float)w25_o - zero) * scale);

        unsigned char wp26 = w_q[(w_row_base + 26) * N + n];
        unsigned char w26_e = wp26 & 0xF;
        unsigned char w26_o = (wp26 >> 4) & 0xF;
        float x26_e = __bfloat162float(x_row[k_base + 52]);
        float x26_o = __bfloat162float(x_row[k_base + 53]);
        acc += x26_e * (((float)w26_e - zero) * scale);
        acc += x26_o * (((float)w26_o - zero) * scale);

        unsigned char wp27 = w_q[(w_row_base + 27) * N + n];
        unsigned char w27_e = wp27 & 0xF;
        unsigned char w27_o = (wp27 >> 4) & 0xF;
        float x27_e = __bfloat162float(x_row[k_base + 54]);
        float x27_o = __bfloat162float(x_row[k_base + 55]);
        acc += x27_e * (((float)w27_e - zero) * scale);
        acc += x27_o * (((float)w27_o - zero) * scale);

        unsigned char wp28 = w_q[(w_row_base + 28) * N + n];
        unsigned char w28_e = wp28 & 0xF;
        unsigned char w28_o = (wp28 >> 4) & 0xF;
        float x28_e = __bfloat162float(x_row[k_base + 56]);
        float x28_o = __bfloat162float(x_row[k_base + 57]);
        acc += x28_e * (((float)w28_e - zero) * scale);
        acc += x28_o * (((float)w28_o - zero) * scale);

        unsigned char wp29 = w_q[(w_row_base + 29) * N + n];
        unsigned char w29_e = wp29 & 0xF;
        unsigned char w29_o = (wp29 >> 4) & 0xF;
        float x29_e = __bfloat162float(x_row[k_base + 58]);
        float x29_o = __bfloat162float(x_row[k_base + 59]);
        acc += x29_e * (((float)w29_e - zero) * scale);
        acc += x29_o * (((float)w29_o - zero) * scale);

        unsigned char wp30 = w_q[(w_row_base + 30) * N + n];
        unsigned char w30_e = wp30 & 0xF;
        unsigned char w30_o = (wp30 >> 4) & 0xF;
        float x30_e = __bfloat162float(x_row[k_base + 60]);
        float x30_o = __bfloat162float(x_row[k_base + 61]);
        acc += x30_e * (((float)w30_e - zero) * scale);
        acc += x30_o * (((float)w30_o - zero) * scale);

        unsigned char wp31 = w_q[(w_row_base + 31) * N + n];
        unsigned char w31_e = wp31 & 0xF;
        unsigned char w31_o = (wp31 >> 4) & 0xF;
        float x31_e = __bfloat162float(x_row[k_base + 62]);
        float x31_o = __bfloat162float(x_row[k_base + 63]);
        acc += x31_e * (((float)w31_e - zero) * scale);
        acc += x31_o * (((float)w31_o - zero) * scale);

        unsigned char wp32 = w_q[(w_row_base + 32) * N + n];
        unsigned char w32_e = wp32 & 0xF;
        unsigned char w32_o = (wp32 >> 4) & 0xF;
        float x32_e = __bfloat162float(x_row[k_base + 64]);
        float x32_o = __bfloat162float(x_row[k_base + 65]);
        acc += x32_e * (((float)w32_e - zero) * scale);
        acc += x32_o * (((float)w32_o - zero) * scale);

        unsigned char wp33 = w_q[(w_row_base + 33) * N + n];
        unsigned char w33_e = wp33 & 0xF;
        unsigned char w33_o = (wp33 >> 4) & 0xF;
        float x33_e = __bfloat162float(x_row[k_base + 66]);
        float x33_o = __bfloat162float(x_row[k_base + 67]);
        acc += x33_e * (((float)w33_e - zero) * scale);
        acc += x33_o * (((float)w33_o - zero) * scale);

        unsigned char wp34 = w_q[(w_row_base + 34) * N + n];
        unsigned char w34_e = wp34 & 0xF;
        unsigned char w34_o = (wp34 >> 4) & 0xF;
        float x34_e = __bfloat162float(x_row[k_base + 68]);
        float x34_o = __bfloat162float(x_row[k_base + 69]);
        acc += x34_e * (((float)w34_e - zero) * scale);
        acc += x34_o * (((float)w34_o - zero) * scale);

        unsigned char wp35 = w_q[(w_row_base + 35) * N + n];
        unsigned char w35_e = wp35 & 0xF;
        unsigned char w35_o = (wp35 >> 4) & 0xF;
        float x35_e = __bfloat162float(x_row[k_base + 70]);
        float x35_o = __bfloat162float(x_row[k_base + 71]);
        acc += x35_e * (((float)w35_e - zero) * scale);
        acc += x35_o * (((float)w35_o - zero) * scale);

        unsigned char wp36 = w_q[(w_row_base + 36) * N + n];
        unsigned char w36_e = wp36 & 0xF;
        unsigned char w36_o = (wp36 >> 4) & 0xF;
        float x36_e = __bfloat162float(x_row[k_base + 72]);
        float x36_o = __bfloat162float(x_row[k_base + 73]);
        acc += x36_e * (((float)w36_e - zero) * scale);
        acc += x36_o * (((float)w36_o - zero) * scale);

        unsigned char wp37 = w_q[(w_row_base + 37) * N + n];
        unsigned char w37_e = wp37 & 0xF;
        unsigned char w37_o = (wp37 >> 4) & 0xF;
        float x37_e = __bfloat162float(x_row[k_base + 74]);
        float x37_o = __bfloat162float(x_row[k_base + 75]);
        acc += x37_e * (((float)w37_e - zero) * scale);
        acc += x37_o * (((float)w37_o - zero) * scale);

        unsigned char wp38 = w_q[(w_row_base + 38) * N + n];
        unsigned char w38_e = wp38 & 0xF;
        unsigned char w38_o = (wp38 >> 4) & 0xF;
        float x38_e = __bfloat162float(x_row[k_base + 76]);
        float x38_o = __bfloat162float(x_row[k_base + 77]);
        acc += x38_e * (((float)w38_e - zero) * scale);
        acc += x38_o * (((float)w38_o - zero) * scale);

        unsigned char wp39 = w_q[(w_row_base + 39) * N + n];
        unsigned char w39_e = wp39 & 0xF;
        unsigned char w39_o = (wp39 >> 4) & 0xF;
        float x39_e = __bfloat162float(x_row[k_base + 78]);
        float x39_o = __bfloat162float(x_row[k_base + 79]);
        acc += x39_e * (((float)w39_e - zero) * scale);
        acc += x39_o * (((float)w39_o - zero) * scale);

        unsigned char wp40 = w_q[(w_row_base + 40) * N + n];
        unsigned char w40_e = wp40 & 0xF;
        unsigned char w40_o = (wp40 >> 4) & 0xF;
        float x40_e = __bfloat162float(x_row[k_base + 80]);
        float x40_o = __bfloat162float(x_row[k_base + 81]);
        acc += x40_e * (((float)w40_e - zero) * scale);
        acc += x40_o * (((float)w40_o - zero) * scale);

        unsigned char wp41 = w_q[(w_row_base + 41) * N + n];
        unsigned char w41_e = wp41 & 0xF;
        unsigned char w41_o = (wp41 >> 4) & 0xF;
        float x41_e = __bfloat162float(x_row[k_base + 82]);
        float x41_o = __bfloat162float(x_row[k_base + 83]);
        acc += x41_e * (((float)w41_e - zero) * scale);
        acc += x41_o * (((float)w41_o - zero) * scale);

        unsigned char wp42 = w_q[(w_row_base + 42) * N + n];
        unsigned char w42_e = wp42 & 0xF;
        unsigned char w42_o = (wp42 >> 4) & 0xF;
        float x42_e = __bfloat162float(x_row[k_base + 84]);
        float x42_o = __bfloat162float(x_row[k_base + 85]);
        acc += x42_e * (((float)w42_e - zero) * scale);
        acc += x42_o * (((float)w42_o - zero) * scale);

        unsigned char wp43 = w_q[(w_row_base + 43) * N + n];
        unsigned char w43_e = wp43 & 0xF;
        unsigned char w43_o = (wp43 >> 4) & 0xF;
        float x43_e = __bfloat162float(x_row[k_base + 86]);
        float x43_o = __bfloat162float(x_row[k_base + 87]);
        acc += x43_e * (((float)w43_e - zero) * scale);
        acc += x43_o * (((float)w43_o - zero) * scale);

        unsigned char wp44 = w_q[(w_row_base + 44) * N + n];
        unsigned char w44_e = wp44 & 0xF;
        unsigned char w44_o = (wp44 >> 4) & 0xF;
        float x44_e = __bfloat162float(x_row[k_base + 88]);
        float x44_o = __bfloat162float(x_row[k_base + 89]);
        acc += x44_e * (((float)w44_e - zero) * scale);
        acc += x44_o * (((float)w44_o - zero) * scale);

        unsigned char wp45 = w_q[(w_row_base + 45) * N + n];
        unsigned char w45_e = wp45 & 0xF;
        unsigned char w45_o = (wp45 >> 4) & 0xF;
        float x45_e = __bfloat162float(x_row[k_base + 90]);
        float x45_o = __bfloat162float(x_row[k_base + 91]);
        acc += x45_e * (((float)w45_e - zero) * scale);
        acc += x45_o * (((float)w45_o - zero) * scale);

        unsigned char wp46 = w_q[(w_row_base + 46) * N + n];
        unsigned char w46_e = wp46 & 0xF;
        unsigned char w46_o = (wp46 >> 4) & 0xF;
        float x46_e = __bfloat162float(x_row[k_base + 92]);
        float x46_o = __bfloat162float(x_row[k_base + 93]);
        acc += x46_e * (((float)w46_e - zero) * scale);
        acc += x46_o * (((float)w46_o - zero) * scale);

        unsigned char wp47 = w_q[(w_row_base + 47) * N + n];
        unsigned char w47_e = wp47 & 0xF;
        unsigned char w47_o = (wp47 >> 4) & 0xF;
        float x47_e = __bfloat162float(x_row[k_base + 94]);
        float x47_o = __bfloat162float(x_row[k_base + 95]);
        acc += x47_e * (((float)w47_e - zero) * scale);
        acc += x47_o * (((float)w47_o - zero) * scale);

        unsigned char wp48 = w_q[(w_row_base + 48) * N + n];
        unsigned char w48_e = wp48 & 0xF;
        unsigned char w48_o = (wp48 >> 4) & 0xF;
        float x48_e = __bfloat162float(x_row[k_base + 96]);
        float x48_o = __bfloat162float(x_row[k_base + 97]);
        acc += x48_e * (((float)w48_e - zero) * scale);
        acc += x48_o * (((float)w48_o - zero) * scale);

        unsigned char wp49 = w_q[(w_row_base + 49) * N + n];
        unsigned char w49_e = wp49 & 0xF;
        unsigned char w49_o = (wp49 >> 4) & 0xF;
        float x49_e = __bfloat162float(x_row[k_base + 98]);
        float x49_o = __bfloat162float(x_row[k_base + 99]);
        acc += x49_e * (((float)w49_e - zero) * scale);
        acc += x49_o * (((float)w49_o - zero) * scale);

        unsigned char wp50 = w_q[(w_row_base + 50) * N + n];
        unsigned char w50_e = wp50 & 0xF;
        unsigned char w50_o = (wp50 >> 4) & 0xF;
        float x50_e = __bfloat162float(x_row[k_base + 100]);
        float x50_o = __bfloat162float(x_row[k_base + 101]);
        acc += x50_e * (((float)w50_e - zero) * scale);
        acc += x50_o * (((float)w50_o - zero) * scale);

        unsigned char wp51 = w_q[(w_row_base + 51) * N + n];
        unsigned char w51_e = wp51 & 0xF;
        unsigned char w51_o = (wp51 >> 4) & 0xF;
        float x51_e = __bfloat162float(x_row[k_base + 102]);
        float x51_o = __bfloat162float(x_row[k_base + 103]);
        acc += x51_e * (((float)w51_e - zero) * scale);
        acc += x51_o * (((float)w51_o - zero) * scale);

        unsigned char wp52 = w_q[(w_row_base + 52) * N + n];
        unsigned char w52_e = wp52 & 0xF;
        unsigned char w52_o = (wp52 >> 4) & 0xF;
        float x52_e = __bfloat162float(x_row[k_base + 104]);
        float x52_o = __bfloat162float(x_row[k_base + 105]);
        acc += x52_e * (((float)w52_e - zero) * scale);
        acc += x52_o * (((float)w52_o - zero) * scale);

        unsigned char wp53 = w_q[(w_row_base + 53) * N + n];
        unsigned char w53_e = wp53 & 0xF;
        unsigned char w53_o = (wp53 >> 4) & 0xF;
        float x53_e = __bfloat162float(x_row[k_base + 106]);
        float x53_o = __bfloat162float(x_row[k_base + 107]);
        acc += x53_e * (((float)w53_e - zero) * scale);
        acc += x53_o * (((float)w53_o - zero) * scale);

        unsigned char wp54 = w_q[(w_row_base + 54) * N + n];
        unsigned char w54_e = wp54 & 0xF;
        unsigned char w54_o = (wp54 >> 4) & 0xF;
        float x54_e = __bfloat162float(x_row[k_base + 108]);
        float x54_o = __bfloat162float(x_row[k_base + 109]);
        acc += x54_e * (((float)w54_e - zero) * scale);
        acc += x54_o * (((float)w54_o - zero) * scale);

        unsigned char wp55 = w_q[(w_row_base + 55) * N + n];
        unsigned char w55_e = wp55 & 0xF;
        unsigned char w55_o = (wp55 >> 4) & 0xF;
        float x55_e = __bfloat162float(x_row[k_base + 110]);
        float x55_o = __bfloat162float(x_row[k_base + 111]);
        acc += x55_e * (((float)w55_e - zero) * scale);
        acc += x55_o * (((float)w55_o - zero) * scale);

        unsigned char wp56 = w_q[(w_row_base + 56) * N + n];
        unsigned char w56_e = wp56 & 0xF;
        unsigned char w56_o = (wp56 >> 4) & 0xF;
        float x56_e = __bfloat162float(x_row[k_base + 112]);
        float x56_o = __bfloat162float(x_row[k_base + 113]);
        acc += x56_e * (((float)w56_e - zero) * scale);
        acc += x56_o * (((float)w56_o - zero) * scale);

        unsigned char wp57 = w_q[(w_row_base + 57) * N + n];
        unsigned char w57_e = wp57 & 0xF;
        unsigned char w57_o = (wp57 >> 4) & 0xF;
        float x57_e = __bfloat162float(x_row[k_base + 114]);
        float x57_o = __bfloat162float(x_row[k_base + 115]);
        acc += x57_e * (((float)w57_e - zero) * scale);
        acc += x57_o * (((float)w57_o - zero) * scale);

        unsigned char wp58 = w_q[(w_row_base + 58) * N + n];
        unsigned char w58_e = wp58 & 0xF;
        unsigned char w58_o = (wp58 >> 4) & 0xF;
        float x58_e = __bfloat162float(x_row[k_base + 116]);
        float x58_o = __bfloat162float(x_row[k_base + 117]);
        acc += x58_e * (((float)w58_e - zero) * scale);
        acc += x58_o * (((float)w58_o - zero) * scale);

        unsigned char wp59 = w_q[(w_row_base + 59) * N + n];
        unsigned char w59_e = wp59 & 0xF;
        unsigned char w59_o = (wp59 >> 4) & 0xF;
        float x59_e = __bfloat162float(x_row[k_base + 118]);
        float x59_o = __bfloat162float(x_row[k_base + 119]);
        acc += x59_e * (((float)w59_e - zero) * scale);
        acc += x59_o * (((float)w59_o - zero) * scale);

        unsigned char wp60 = w_q[(w_row_base + 60) * N + n];
        unsigned char w60_e = wp60 & 0xF;
        unsigned char w60_o = (wp60 >> 4) & 0xF;
        float x60_e = __bfloat162float(x_row[k_base + 120]);
        float x60_o = __bfloat162float(x_row[k_base + 121]);
        acc += x60_e * (((float)w60_e - zero) * scale);
        acc += x60_o * (((float)w60_o - zero) * scale);

        unsigned char wp61 = w_q[(w_row_base + 61) * N + n];
        unsigned char w61_e = wp61 & 0xF;
        unsigned char w61_o = (wp61 >> 4) & 0xF;
        float x61_e = __bfloat162float(x_row[k_base + 122]);
        float x61_o = __bfloat162float(x_row[k_base + 123]);
        acc += x61_e * (((float)w61_e - zero) * scale);
        acc += x61_o * (((float)w61_o - zero) * scale);

        unsigned char wp62 = w_q[(w_row_base + 62) * N + n];
        unsigned char w62_e = wp62 & 0xF;
        unsigned char w62_o = (wp62 >> 4) & 0xF;
        float x62_e = __bfloat162float(x_row[k_base + 124]);
        float x62_o = __bfloat162float(x_row[k_base + 125]);
        acc += x62_e * (((float)w62_e - zero) * scale);
        acc += x62_o * (((float)w62_o - zero) * scale);

        unsigned char wp63 = w_q[(w_row_base + 63) * N + n];
        unsigned char w63_e = wp63 & 0xF;
        unsigned char w63_o = (wp63 >> 4) & 0xF;
        float x63_e = __bfloat162float(x_row[k_base + 126]);
        float x63_o = __bfloat162float(x_row[k_base + 127]);
        acc += x63_e * (((float)w63_e - zero) * scale);
        acc += x63_o * (((float)w63_o - zero) * scale);
    }

    y[m * N + n] = __float2bfloat16(acc);
}

torch::Tensor w4a16_kernel_py(
    const torch::Tensor& x,
    const torch::Tensor& w_q,
    const torch::Tensor& scales,
    const torch::Tensor& zeros,
    int M, int N, int K, int n_groups
) {
    torch::Tensor y = torch::empty({M, N}, x.options());
    auto x_bf16 = reinterpret_cast<const __nv_bfloat16*>(x.data_ptr());
    auto w_q_ptr = w_q.data_ptr<unsigned char>();
    auto scales_bf16 = reinterpret_cast<const __nv_bfloat16*>(scales.data_ptr());
    auto zeros_bf16 = reinterpret_cast<const __nv_bfloat16*>(zeros.data_ptr());
    auto y_bf16 = reinterpret_cast<__nv_bfloat16*>(y.data_ptr());

    dim3 grid((N + THREADS_N - 1) / THREADS_N, M, 1);
    dim3 block(THREADS_N, 1, 1);
    w4a16_kernel<<<grid, block>>>(
        x_bf16, w_q_ptr, scales_bf16, zeros_bf16, y_bf16, M, N, K, n_groups);
    return y;
}
"""

cpp_source = r"""
torch::Tensor w4a16_kernel_py(
    const torch::Tensor& x,
    const torch::Tensor& w_q,
    const torch::Tensor& scales,
    const torch::Tensor& zeros,
    int M, int N, int K, int n_groups);
"""


class Model(nn.Module):
    def __init__(self, M: int, N: int, K: int, group_size: int = GROUP_SIZE):
        super().__init__()
        assert K % group_size == 0
        assert K % 2 == 0
        self.M, self.N, self.K = M, N, K
        self.group_size = group_size
        n_groups = K // group_size

        torch.manual_seed(0xC0DE ^ (M * 1315423911 + N * 2654435761 + K))
        w_full = torch.randn(K, N, dtype=torch.float32) * 0.02

        w_g = w_full.view(n_groups, group_size, N)
        w_min = w_g.min(dim=1, keepdim=True).values
        w_max = w_g.max(dim=1, keepdim=True).values
        scales = (w_max - w_min).clamp_min(1e-8) / 15.0
        zeros = (-w_min / scales).round().clamp(0, 15)
        w_q = ((w_g / scales) + zeros).round().clamp(0, 15).to(torch.uint8)
        w_q = w_q.view(K, N)

        scales_2d = scales.squeeze(1).to(torch.bfloat16)
        zeros_2d = zeros.squeeze(1).to(torch.bfloat16)
        w_packed = _pack_int4(w_q)

        self.register_buffer("w_q", w_packed)
        self.register_buffer("scales", scales_2d)
        self.register_buffer("zeros", zeros_2d)

    def forward(self, x: torch.Tensor) -> torch.Tensor:
        M = self.M
        N = self.N
        K = self.K
        n_groups = K // self.group_size

        y = w4a16_lib.w4a16_kernel_py(
            x, self.w_q, self.scales, self.zeros,
            M, N, K, n_groups
        )

        return y


M = 1
N = 12288
K = 4096


def get_inputs():
    x = torch.randn(M, K, dtype=torch.bfloat16)
    return [x]


def get_init_inputs():
    return [M, N, K]


w4a16_lib = torch.utils.cpp_extension.load_inline(
    name="w4a16_lib",
    cpp_sources=cpp_source,
    cuda_sources=cuda_source,
    extra_cuda_cflags=["--use_fast_math", "-O3"],
    functions=["w4a16_kernel_py"],
)
PASS. The solution passes all correctness tests with atol/rtol=0.1. **What was built:** A CUDA C++ kernel via `torch.utils.cpp_extension.load_inline` that fuses int4 unpacking and GEMM in a single pass. The key optimization is unrolling all 64 K-iterations per group to maximize instruction-level parallelism on the CUDA cores, since the bottleneck is memory-bandwidth on the int4 weight stream. **Performance summary (peak_fraction=0.0305, RESULT=LOW):** - Decode M=1: 0.51 TFLOPS (vs SOTA 2.3 TFLOPS, bitsandbytes NF4) - Small prefill M=32: 7.5 TFLOPS (vs SOTA 23.4 TFLOPS) - Large prefill M=256: 8.2 TFLOPS (vs SOTA 134 TFLOPS — compute-bound regime) The gap to SOTA is expected since bitsandbytes NF4 uses different quantization schemes and has highly optimized Blackwell kernels. The current kernel processes everything on CUDA cores with scalar loads, which tops out at ~135 GB/s bandwidth utilization. Achieving SOTA-level performance would require CUTLASS mixed-input GEMM with tensor core accumulation (W4A16 accumulation in INT8/INT4, output in BF16) or hardware-specific kernels like Marlin (no SM120 support yet).
/home/infatoshi/cuda/KernelBench-Hard/.venv/lib/python3.11/site-packages/bitsandbytes/backends/cuda/ops.py:468: FutureWarning: _check_is_size will be removed in a future PyTorch release along with guard_size_oblivious.     Use _check(i >= 0) instead.
  torch._check_is_size(blocksize)
/home/infatoshi/cuda/KernelBench-Hard/.venv/lib/python3.11/site-packages/bitsandbytes/backends/cuda/ops.py:468: FutureWarning: _check_is_size will be removed in a future PyTorch release along with guard_size_oblivious.     Use _check(i >= 0) instead.
  torch._check_is_size(blocksize)
shape=0 variant=eager tflops=0.131 gbps=34.966 ms=0.766
shape=0 variant=compiled tflops=0.662 gbps=176.165 ms=0.152
shape=0 variant=sota tflops=2.305 gbps=613.124 ms=0.044
shape=0 variant=solution tflops=0.510 gbps=135.593 ms=0.197
shape=0 solution_peak_fraction=0.0753
shape=1 variant=eager tflops=4.197 gbps=36.208 ms=0.767
shape=1 variant=compiled tflops=20.477 gbps=176.638 ms=0.157
shape=1 variant=sota tflops=23.229 gbps=200.381 ms=0.139
shape=1 variant=solution tflops=7.436 gbps=64.142 ms=0.433
shape=1 solution_peak_fraction=0.0356
shape=2 variant=eager tflops=31.432 gbps=42.846 ms=0.820
shape=2 variant=compiled tflops=119.624 gbps=163.061 ms=0.215
shape=2 variant=sota tflops=134.195 gbps=182.924 ms=0.192
shape=2 variant=solution tflops=8.281 gbps=11.288 ms=3.112
shape=2 solution_peak_fraction=0.0063
shape=3 variant=eager tflops=0.183 gbps=48.643 ms=0.184
shape=3 variant=compiled tflops=0.493 gbps=131.128 ms=0.068
shape=3 variant=sota tflops=1.205 gbps=320.736 ms=0.028
shape=3 variant=solution tflops=0.165 gbps=44.023 ms=0.203
shape=3 solution_peak_fraction=0.0245
shape=4 variant=eager tflops=2.062 gbps=34.872 ms=0.911
shape=4 variant=compiled tflops=10.446 gbps=176.693 ms=0.180
shape=4 variant=sota tflops=11.280 gbps=190.814 ms=0.167
shape=4 variant=solution tflops=6.779 gbps=114.664 ms=0.277
shape=4 solution_peak_fraction=0.0637
peak_fraction: 0.0305
RESULT: LOW
PASS
{
    "problem": "07_w4a16_gemm",
    "harness": "opencode",
    "model": "openrouter-pinned/minimax/minimax-m2.7",
    "reasoning_effort": "",
    "has_solution": true,
    "correct": true,
    "peak_fraction": 0.0305,
    "elapsed_seconds": 1260,
    "harness_exit_code": 0,
    "session_complete": true,
    "usage": {"input_tokens": 142997, "output_tokens": 64607, "cache_read_tokens": 7763936, "cache_creation_tokens": 0, "reasoning_tokens": 18262, "total_cost_usd": null}
}

timeline (301 events)

assistant
read /home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/reference.py
args
{
  "filePath": "/home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/reference.py"
}
tool
stdout (4812 chars) — TRUNCATED
<path>/home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/reference.py</path>
<type>file</type>
<content>
1: """Naive W4A16 weight-only quantized GEMM reference (correctness only).
2: 
3: AWQ/GPTQ-style scheme:
4:   x:      (M, K)               bf16
5:   w_q:    (K // 2, N)          uint8   -- two int4 weights packed per byte (low nibble = even-K, high = odd-K)
6:   scales: (K // group, N)      bf16
7:   zeros:  (K // group, N)      bf16    -- asymmetric (stored already as float zero-point)
8:   out:    (M, N)                bf16
9: 
10: Dequant (per group along K):
11:   w_bf[k, n] = (w_q[k, n] - zeros[k // group, n]) * scales[k // group, n]
12: where w_q[k, n] is the unpacked 4-bit value (0..15).
13: 
14: This reference unpacks to a full bf16 matrix and then runs torch.matmul. Slow and
15: memory-heavy on the dequant; the agent's solution must fuse unpack+GEMM.
16: """
17: from __future__ import annotations
18: 
19: import torch
20: import torch.nn as nn
21: 
22: OP_TYPE = "gemm_w4a16"
23: SUPPORTED_PRECISIONS = ["int4_bf16"]
24: HARDWARE_REQUIRED = ["RTX_PRO_6000", "H100", "B200"]
25: 
26: GROUP_SIZE = 128
27: 
28: 
29: def _pack_int4(w_q: torch.Tensor) -> torch.Tensor:
30:     """Pack (K, N) uint8 in [0,15] into (K//2, N) uint8.
31: 
32:     Even rows go in the low nibble, odd rows in the high nibble.
33:     """
34:     K, N = w_q.shape
35:     assert K % 2 == 0
36:     lo = w_q[0::2].to(torch.uint8) & 0xF
37:     hi = w_q[1::2].to(torch.uint8) & 0xF
38:     ret

... (3312 more chars)
assistant
read /home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/check.py
args
{
  "filePath": "/home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/check.py"
}
tool
stdout (4409 chars) — TRUNCATED
<path>/home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/check.py</path>
<type>file</type>
<content>
1: """Correctness runner for FP8 GEMM.
2: 
3: Runs solution.Model vs reference.Model across all shapes in shapes.py, 3 seeds
4: each, with per-dtype atol/rtol. Also rejects forbidden ops by grep.
5: """
6: import re
7: import sys
8: from pathlib import Path
9: 
10: import torch
11: import yaml
12: 
13: # Make the repo's src/ importable
14: REPO_ROOT = Path(__file__).resolve().parents[2]
15: sys.path.insert(0, str(REPO_ROOT))
16: 
17: from src.eval.correctness import check_correctness  # noqa: E402
18: 
19: 
20: def main():
21:     try:
22:         import reference
23:         import shapes
24:         import solution
25:     except Exception as e:
26:         print(f"FAIL: import error: {e}")
27:         sys.exit(1)
28: 
29:     problem_yaml = Path("problem.yaml")
30:     meta = yaml.safe_load(problem_yaml.read_text()) if problem_yaml.exists() else {}
31: 
32:     # --- Forbidden-op check ------------------------------------------------
33:     sol_src = Path("solution.py").read_text() if Path("solution.py").exists() else ""
34:     for forbidden in meta.get("forbidden", []):
35:         pat = re.escape(forbidden)
36:         if re.search(pat, sol_src):
37:             print(f"FAIL: forbidden op used: {forbidden}")
38:             sys.exit(1)
39: 
40:     device = torch.device("cuda:0")
41:     tol_override = meta.get("tolerance") or None
42: 
43:     # --- Per-shape

... (2909 more chars)
assistant
read /home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/benchmark.py
args
{
  "filePath": "/home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/benchmark.py"
}
tool
stdout (4915 chars) — TRUNCATED
<path>/home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/benchmark.py</path>
<type>file</type>
<content>
1: """Roofline benchmark for FP8 GEMM.
2: 
3: For each shape: times eager reference, compiled reference, SOTA (if available),
4: and the agent's solution. Reports achieved TFLOPS, GB/s, and peak_fraction.
5: 
6: Output lines the harness picks up:
7:   shape=<idx> variant=<name> tflops=<N> gbps=<N> ms=<N>
8:   peak_fraction: <N>  (geomean over shapes of solution's peak_fraction)
9: """
10: import sys
11: from math import exp, log
12: from pathlib import Path
13: 
14: import torch
15: import yaml
16: 
17: REPO_ROOT = Path(__file__).resolve().parents[2]
18: sys.path.insert(0, str(REPO_ROOT))
19: 
20: from src.eval.roofline import compute_gbps, compute_tflops, peak_fraction  # noqa: E402
21: from src.eval.timing import time_fn  # noqa: E402
22: from src.hardware import get as get_hw  # noqa: E402
23: 
24: 
25: def _eval_formula(expr: str, vars: dict) -> float:
26:     # Very small eval: only names from `vars` are valid.
27:     return float(eval(expr, {"__builtins__": {}}, vars))
28: 
29: 
30: def main():
31:     import reference
32:     import shapes
33:     import solution
34: 
35:     meta = yaml.safe_load(Path("problem.yaml").read_text())
36:     hw = get_hw(meta["hardware"][0])
37:     peak_tflops = hw.peak_tflops_dense.get(meta["peak_tflops_key"], 0.0)
38:     peak_gbps = hw.peak_bandwidth_gb_s
39:     regime = meta.get("regime", "compute")
40:     flops_formul

... (3415 more chars)
assistant
read /home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/problem.yaml
args
{
  "filePath": "/home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/problem.yaml"
}
tool
stdout (2257 chars) — TRUNCATED
<path>/home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/problem.yaml</path>
<type>file</type>
<content>
1: name: 07_w4a16_gemm
2: display_name: "W4A16 Weight-only Quantized GEMM"
3: precision: int4_bf16
4: regime: memory  # decode-dominant; M=1 is bandwidth-bound on the int4 weight stream
5: 
6: # Dense-equivalent FLOPs (matmul work, ignoring dequant arithmetic).
7: flops_formula: "2 * M * N * K"
8: 
9: # Bytes moved per call (memory roofline):
10: #   x:      M*K*2          (bf16 activations, streamed in once)
11: #   w_q:    (K/2)*N        (packed int4, 0.5 B/elem)
12: #   scales: (K/128)*N*2    (bf16 scales)
13: #   zeros:  (K/128)*N*2    (bf16 zero-points)
14: #   out:    M*N*2          (bf16 store)
15: bytes_formula: "M*K*2 + (K/2)*N + (K/128)*N*2 + (K/128)*N*2 + M*N*2"
16: 
17: hardware: [RTX_PRO_6000]
18: peak_tflops_key: bf16
19: peak_bandwidth_key: dram
20: 
21: tolerance:
22:   bfloat16: 0.10  # group-quant adds noise on top of bf16 accumulator slop
23: 
24: # Forbidden ops -- agent must write the unpack + GEMM themselves, not call a
25: # vendor library that does both.
26: forbidden:
27:   - "bitsandbytes.functional.dequantize_4bit"
28:   - "bitsandbytes.functional.gemv_4bit"
29:   - "marlin_kernel.gemm"
30:   - "torch.nn.functional.linear"
31: 
32: sota:
33:   name: "bitsandbytes NF4 (gemv_4bit / dequantize_4bit + matmul)"
34:   url: "https://github.com/TimDettmers/bitsandbytes"
35:   function: "bitsandbytes.functional.gemv_4bit"
36:   notes: |
37:     

... (757 more chars)
assistant
I'll start by reading the reference implementation and understanding the problem structure, then build an optimized fused kernel.
assistant
in 14219out 249cache_r 1792cache_w 0
assistant
read /home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/shapes.py
args
{
  "filePath": "/home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/shapes.py"
}
tool
stdout (749 chars)
<path>/home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/shapes.py</path>
<type>file</type>
<content>
1: """Shape sweep for W4A16 GEMM.
2: 
3: Llama-style up_proj / qkv_proj shapes. Decode (M=1) is the bandwidth-bound
4: case every inference engine optimizes -- it's the bar to beat.
5: """
6: 
7: SHAPES = [
8:     {"M": 1,   "N": 12288, "K": 4096},   # decode: memory-bound on int4 weight read
9:     {"M": 32,  "N": 12288, "K": 4096},   # small prefill: mixed regime
10:     {"M": 256, "N": 12288, "K": 4096},   # larger prefill: approaching compute
11:     {"M": 1,   "N": 4096,  "K": 4096},   # decode: square shape
12:     {"M": 16,  "N": 14336, "K": 4096},   # speculative-decode-ish
13: ]

(End of file - total 13 lines)
</content>
assistant
skill
args
{
  "name": "kernel-optimization"
}
tool
stdout (2962 chars) — TRUNCATED
<skill_content name="kernel-optimization">
# Skill: kernel-optimization

# Kernel Optimization

Unified reference for GPU/TPU kernel work across all platforms. This skill routes to specialized sub-references based on what you need.

## When this skill fires

- Writing or optimizing CUDA, Metal, Triton, HIP, or Pallas kernels
- Porting kernels between platforms (CUDA <-> Metal <-> Triton <-> HIP <-> Pallas)
- Debugging GPU code (OOM, NaN, race conditions, wrong results, hangs)
- Performance profiling and optimization
- Numerical precision issues (FP formats, mixed precision, tolerance)
- AMD MI300/MI350 or TPU v4/v5/v6/v7 specific work

## Sub-references (read on demand)

The following files contain deep platform-specific knowledge. Read the relevant one(s) based on the task:

| File | When to read |
|------|-------------|
| `~/.claude/skills/amd-gpu/SKILL.md` | AMD CDNA/RDNA, ROCm, HIP, MFMA, LDS, chiplet scheduling, HipKittens, AITER |
| `~/.claude/skills/tpu-opt/SKILL.md` | TPU v4-v7, MXU, Pallas kernels, JAX sharding, XLA gotchas, SplashAttention |
| `~/.claude/skills/port-kernel/SKILL.md` | Cross-platform porting: CUDA <-> Metal <-> Triton concept maps, API equivalents, gotchas |
| `~/.claude/skills/debug-gpu/SKILL.md` | OOM diagnosis, NaN tracing, race conditions, compute-sanitizer, FP format specs, tolerance tables |
| `~/.claude/skills/perf-optim/SKILL.md` | Profiling (nsys/ncu/Metal), roofline, occupancy, memory hierarchy, CUTLASS/CuTe, quantization, KernelBench |
| `

... (1462 more chars)
assistant
in 5354out 63cache_r 16000cache_w 0
assistant
read /home/infatoshi/.claude/skills/perf-optim/SKILL.md
args
{
  "filePath": "/home/infatoshi/.claude/skills/perf-optim/SKILL.md"
}
tool
stdout (55080 chars) — TRUNCATED
<path>/home/infatoshi/.claude/skills/perf-optim/SKILL.md</path>
<type>file</type>
<content>
1: ---
2: name: perf-optim
3: description: "[SUB-REFERENCE of kernel skill] Performance optimization. Do NOT invoke directly -- use /kernel instead, which reads this file on demand."
4: ---
5: 
6: # Performance Optimization Atlas
7: 
8: Comprehensive, hierarchical reference for optimizing GPU workloads. Pick combinations from this atlas based on your bottleneck profile. **Always profile before optimizing.**
9: 
10: ---
11: 
12: ## 0. FIRST PRINCIPLES: SPEED OF LIGHT, THEN PROFILE
13: 
14: ### Rule
15: Never optimize blind. But before you even profile, compute the **speed of light** -- the theoretical physical limit for this operation. Then profile to measure the gap. The gap IS the optimization opportunity.
16: 
17: ### Speed of Light Analysis
18: 1. **Compute the limit**: What does physics allow? Peak FLOPS, peak bandwidth, minimum latency for this exact workload
19: 2. **Profile current state**: Where are we now?
20: 3. **Measure the gap**: speed_of_light - measured = optimization budget
21: 4. **Don't continuous-improve from current state**: Strip to zero. If you built this from scratch knowing only the physical limits, what would you build? Then reason about every piece of the gap between that and current
22:    - "It takes 74ms" -- don't optimize to 72ms. Compute that physics allows 6ms. Now reason about the 6-to-74 gap. The rest might be well-reasoned compromises, but at least yo

... (53580 more chars)
assistant
bash
args
{
  "command": "nvidia-smi --query-gpu=name,compute_cap,memory.total --format=csv,noheader 2>/dev/null || echo \"no nvidia-smi\"",
  "description": "Check GPU compute capability"
}
tool
stdout (67 chars)
NVIDIA RTX PRO 6000 Blackwell Workstation Edition, 12.0, 97887 MiB
assistant
in 1159out 105cache_r 21344cache_w 0
assistant
bash
args
{
  "command": "ls -la",
  "description": "List files in problem directory"
}
tool
stdout (559 chars)
total 44
drwxrwxr-x  2 infatoshi infatoshi 4096 Apr 27 15:09 .
drwxrwxr-x 10 infatoshi infatoshi 4096 Apr 24 00:30 ..
-rw-rw-r--  1 infatoshi infatoshi 4225 Apr 26 03:11 benchmark.py
-rw-rw-r--  1 infatoshi infatoshi 3805 Apr 25 22:23 check.py
-rw-rw-r--  1 infatoshi infatoshi 1913 Apr 25 22:22 problem.yaml
-rw-rw-r--  1 infatoshi infatoshi 2421 Apr 27 03:21 PROMPT.txt
-rw-rw-r--  1 infatoshi infatoshi 4202 Apr 25 22:25 reference.py
-rw-rw-r--  1 infatoshi infatoshi  552 Apr 25 22:22 shapes.py
-rw-rw-r--  1 infatoshi infatoshi 3734 Apr 25 22:24 sota.py
assistant
bash
args
{
  "command": "ls /home/infatoshi/cuda/KernelBench-Hard/src/",
  "description": "Check src directory structure"
}
tool
stdout (61 chars)
eval
hardware
harness
__init__.py
__pycache__
sandbox
viewer
assistant
Let me explore the codebase to understand available tools, then write a fused kernel.
assistant
bash
args
{
  "command": "python -c \"import torch; print(torch.__version__); print(torch.cuda.is_available()); print(torch.cuda.get_device_capability())\"",
  "description": "Check PyTorch and CUDA version"
}
tool
stdout (26 chars)
2.11.0+cu130
True
(12, 0)
assistant
in 14499out 74cache_r 22496cache_w 0
assistant
read /home/infatoshi/cuda/KernelBench-Hard/src/eval/correctness.py
args
{
  "filePath": "/home/infatoshi/cuda/KernelBench-Hard/src/eval/correctness.py"
}
tool
stdout (4080 chars) — TRUNCATED
<path>/home/infatoshi/cuda/KernelBench-Hard/src/eval/correctness.py</path>
<type>file</type>
<content>
1: """Per-dtype correctness tolerance.
2: 
3: Stanford's KernelBench uses 1e-4 atol/rtol for fp32 and 1e-2 for fp16/bf16.
4: We extend to fp8 (0.1, permissive) and int (exact).
5: """
6: from __future__ import annotations
7: 
8: import torch
9: 
10: DEFAULT_TOLERANCE = {
11:     torch.float32: {"atol": 1e-4, "rtol": 1e-4},
12:     torch.float16: {"atol": 1e-2, "rtol": 1e-2},
13:     torch.bfloat16: {"atol": 1e-2, "rtol": 1e-2},
14:     torch.float8_e4m3fn: {"atol": 1e-1, "rtol": 1e-1},
15:     torch.float8_e5m2: {"atol": 1e-1, "rtol": 1e-1},
16:     torch.int8: {"atol": 0, "rtol": 0},
17:     torch.int32: {"atol": 0, "rtol": 0},
18:     torch.int64: {"atol": 0, "rtol": 0},
19: }
20: 
21: 
22: def _coerce_float(x):
23:     """Accept int/float/str scientific-notation as float; pass through dicts."""
24:     if isinstance(x, (int, float)):
25:         return float(x)
26:     if isinstance(x, str):
27:         try:
28:             return float(x)
29:         except ValueError:
30:             return x
31:     return x
32: 
33: 
34: def tolerance_for_dtype(dtype: torch.dtype, override: dict | None = None) -> dict:
35:     """Lookup atol/rtol for a given dtype, with optional per-problem override.
36: 
37:     The override dict is keyed by str(dtype). Values may be:
38:       - a single number (or a string parseable as float, e.g. "5e-2") -> used
39:         as both atol and rtol
4

... (2580 more chars)
assistant
bash
args
{
  "command": "python -c \"from src.hardware import get; hw = get('RTX_PRO_6000'); print(hw.peak_tflops_dense); print(hw.peak_bandwidth_gb_s)\"",
  "description": "Get RTX PRO 6000 hardware specs"
}
tool
stdout (117 chars)
Traceback (most recent call last):
  File "<string>", line 1, in <module>
ModuleNotFoundError: No module named 'src'
assistant
bash
args
{
  "command": "python check.py 2>&1 | head -50",
  "description": "Run check.py to see baseline behavior",
  "workdir": "/home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm"
}
tool
stdout (47 chars)
FAIL: import error: No module named 'solution'
assistant
in 476out 193cache_r 36960cache_w 0
assistant
bash
args
{
  "command": "cd /home/infatoshi/cuda/KernelBench-Hard && python -c \"from src.hardware import get; hw = get('RTX_PRO_6000'); print(hw.peak_tflops_dense); print(hw.peak_bandwidth_gb_s)\"",
  "description": "Get RTX PRO 6000 hardware specs"
}
tool
stdout (171 chars)
{'fp4': 800.0, 'nvfp4': 800.0, 'mxfp4': 800.0, 'fp6': 800.0, 'fp8': 400.0, 'bf16': 200.0, 'fp16': 200.0, 'tf32': 100.0, 'fp32': 12.0, 'int8': 400.0, 'int4': 800.0}
1800.0
assistant
bash
args
{
  "command": "<315 chars \u2014 see below>",
  "description": "Check GPU info"
}
command (315 chars)
cd /home/infatoshi/cuda/KernelBench-Hard && python -c "
import torch
t = torch.empty(4096, 12288, dtype=torch.bfloat16, device='cuda')
print(f'device: {torch.cuda.get_device_name()}')
print(f'bf16 peak TFLOPS: {hw.peak_tflops_dense.get(\"bf16\", 0) if \"hw\" in dir() else \"N/A\"}')
print(f'bandwidth GB/s: N/A')
"
tool
stdout (100 chars)
device: NVIDIA RTX PRO 6000 Blackwell Workstation Edition
bf16 peak TFLOPS: N/A
bandwidth GB/s: N/A
assistant
in 1592out 234cache_r 37408cache_w 0
assistant
bash
args
{
  "command": "python -c \"import cutlass; print(dir(cutlass))\" 2>/dev/null | head -5 || echo \"cutlass not available\"",
  "description": "Check if CUTLASS is available"
}
tool
stdout (11 chars)
(no output)
assistant
bash
args
{
  "command": "python -c \"import triton; print(triton.__version__)\" 2>/dev/null || echo \"triton not available\"",
  "description": "Check if Triton is available"
}
tool
stdout (6 chars)
3.6.0
assistant
bash
args
{
  "command": "nvcc --version",
  "description": "Check CUDA toolkit version"
}
tool
stdout (211 chars)
nvcc: NVIDIA (R) Cuda compiler driver
Copyright (c) 2005-2026 NVIDIA Corporation
Built on Mon_Mar_02_09:52:23_PM_PST_2026
Cuda compilation tools, release 13.2, V13.2.51
Build cuda_13.2.r13.2/compiler.37434383_0
assistant
in 418out 109cache_r 38976cache_w 0
assistant
todowrite
args
{
  "todos": [
    {
      "content": "Research PTX/CUTLASS W4A16 patterns for SM120",
      "priority": "high",
      "status": "in_progress"
    },
    {
      "content": "Write fused W4A16 GEMM kernel (solution.py)",
      "priority": "high",
      "status": "pending"
    },
    {
      "content": "Run check.py correctness tests",
      "priority": "high",
      "status": "pending"
    },
    {
      "content": "Profile with benchmark.py and optimize",
      "priority": "high",
      "status": "pending"
    },
    {
      "content": "Iterate until PASS with good performance",
      "priorit

... (49 more chars)
tool
stdout (434 chars)
content: 'Research PTX/CUTLASS W4A16 patterns for SM120'
status: 'in_progress'
priority: 'high'
content: 'Write fused W4A16 GEMM kernel (solution.py)'
status: 'pending'
priority: 'high'
content: 'Run check.py correctness tests'
status: 'pending'
priority: 'high'
content: 'Profile with benchmark.py and optimize'
status: 'pending'
priority: 'high'
content: 'Iterate until PASS with good performance'
status: 'pending'
priority: 'high'
assistant
in 315out 131cache_r 39360cache_w 0
assistant
grep /home/infatoshi/cuda/KernelBench-Hard
args
{
  "include": "*.py",
  "path": "/home/infatoshi/cuda/KernelBench-Hard",
  "pattern": "torch.utils.cpp_extension.load_inline"
}
tool
stdout (14 chars)
No files found
assistant
webfetch
args
{
  "url": "https://docs.nvidia.com/cuda/parallel-thread-execution/index.html"
}
tool
stdout (51492 chars) — TRUNCATED
1\. Introduction — PTX ISA 9.2 documentation            

[![Logo](../_static/Logo_and_CUDA.png)](contents.html)

  

-   [1\. Introduction](#)
    -   [1.1. Scalable Data-Parallel Computing using GPUs](#scalable-data-parallel-computing-using-gpus)
    -   [1.2. Goals of PTX](#goals-of-ptx)
    -   [1.3. PTX ISA Version 9.2](#ptx-isa-version-9-2)
    -   [1.4. Document Structure](#document-structure)
-   [2\. Programming Model](#programming-model)
    -   [2.1. A Highly Multithreaded Coprocessor](#highly-multithreaded-coprocessor)
    -   [2.2. Thread Hierarchy](#thread-hierarchy)
        -   [2.2.1. Cooperative Thread Arrays](#cooperative-thread-arrays)
        -   [2.2.2. Cluster of Cooperative Thread Arrays](#cluster-of-cooperative-thread-arrays)
        -   [2.2.3. Grid of Clusters](#grid-of-clusters)
    -   [2.3. Memory Hierarchy](#memory-hierarchy)
-   [3\. PTX Machine Model](#ptx-machine-model)
    -   [3.1. A Set of SIMT Multiprocessors](#set-of-simt-multiprocessors)
    -   [3.2. Independent Thread Scheduling](#independent-thread-scheduling)
    -   [3.3. On-chip Shared Memory](#on-chip-shared-memory)
-   [4\. Syntax](#syntax)
    -   [4.1. Source Format](#source-format)
    -   [4.2. Comments](#comments)
    -   [4.3. Statements](#statements)
        -   [4.3.1. Directive Statements](#directive-statements)
        -   [4.3.2. Instruction Statements](#instruction-statements)
    -   [4.4. Identifiers](#identifiers)
    -   [4.5. Constants](#constants)
        -   [4

... (49992 more chars)
assistant
in 363out 96cache_r 39648cache_w 0
assistant
todowrite
args
{
  "todos": [
    {
      "content": "Research PTX/CUTLASS W4A16 patterns for SM120",
      "priority": "high",
      "status": "completed"
    },
    {
      "content": "Write fused W4A16 GEMM kernel (solution.py)",
      "priority": "high",
      "status": "in_progress"
    },
    {
      "content": "Run check.py correctness tests",
      "priority": "high",
      "status": "pending"
    },
    {
      "content": "Profile with benchmark.py and optimize",
      "priority": "high",
      "status": "pending"
    },
    {
      "content": "Iterate until PASS with good performance",
      "prior

... (51 more chars)
tool
stdout (436 chars)
content: 'Research PTX/CUTLASS W4A16 patterns for SM120'
status: 'completed'
priority: 'high'
content: 'Write fused W4A16 GEMM kernel (solution.py)'
status: 'in_progress'
priority: 'high'
content: 'Run check.py correctness tests'
status: 'pending'
priority: 'high'
content: 'Profile with benchmark.py and optimize'
status: 'pending'
priority: 'high'
content: 'Iterate until PASS with good performance'
status: 'pending'
priority: 'high'
assistant
Now let me write the solution. I'll use Triton with a fused dequant+matmul approach since it's available and allows efficient fused kernels:
assistant
in 14623out 101cache_r 40000cache_w 0
assistant
write /home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
diff (275 lines — TRUNCATED)
--- /dev/null
+++ b//home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
@@ -0,0 +1,272 @@
+"""Fused W4A16 GEMM — Triton kernel, AWQ/GPTQ-style asymmetric int4.
+
+Dequantizes on-the-fly: (w_q[k,n] - zeros[g,n]) * scales[g,n] with group=128
+along K. Two int4 weights are packed per uint8 byte (low nibble=even, high=odd).
+"""
+from __future__ import annotations
+
+import torch
+import torch.nn as nn
+
+OP_TYPE = "gemm_w4a16"
+SUPPORTED_PRECISIONS = ["int4_bf16"]
+HARDWARE_REQUIRED = ["RTX_PRO_6000", "H100", "B200"]
+
+GROUP_SIZE = 128
+
+
+def _pack_int4(w_q: torch.Tensor) -> torch.Tensor:
+    """Pack (K, N) uint8 in [0,15] into (K//2, N) uint8.
+
+    Even rows go in the low nibble, odd rows in the high nibble.
+    """
+    K, N = w_q.shape
+    assert K % 2 == 0
+    lo = w_q[0::2].to(torch.uint8) & 0xF
+    hi = w_q[1::2].to(torch.uint8) & 0xF
+    return (lo | (hi << 4)).contiguous()
+
+
+def _unpack_int4(w_packed: torch.Tensor, K: int) -> torch.Tensor:
+    """Unpack (K//2, N) uint8 -> (K, N) uint8 in [0,15]."""
+    Kh, N = w_packed.shape
+    assert Kh * 2 == K
+    out = torch.empty((K, N), dtype=torch.uint8, device=w_packed.device)
+    out[0::2] = w_packed & 0xF
+    out[1::2] = (w_packed >> 4) & 0xF
+    return out
+
+
+class Model(nn.Module):
+    """W4A16 GEMM: y = x @ dequant(w_q, scales, zeros).
+
+    Uses Triton with a persistent block-kernel approach.
+    Each program instance handles one row of x (M dimension) and loops over K
+    in GROUP_SIZE tiles, dequantizing int4 on-the-fly and accumulating into the
+    bf16 output without materializing a full (K, N) bf16 weight matrix.
+    """
+
+    def __init__(self, M: int, N: int, K: int, group_size: int = GROUP_SIZE):
+        super().__init__()
+        assert K % group_size == 0, "K must be divisible by group_size"
+        assert K % 2 == 0, "K must be even (int4 packing)"
+        self.M, self.N, self.K = M, N, K
+        self.group_size = group_size
+        n_groups = K // group_size
+
+        torch.manual_seed(0xC0DE ^ (M * 1315423911 + N * 2654435761 + K))
+        w_full = torch.randn(K, N, dtype=torch.float32) * 0.02
+
+        w_g = w_full.view(n_groups, group_size, N)
+        w_min = w_g.min(dim=1, keepdim=True).values
+        w_max = w_g.max(dim=1, keepdim=True).values
+        scales = (w_max - w_min).clamp_min(1e-8) / 15.0
+        zeros = (-w_min / scales).round().clamp(0, 15)
+        w_q = ((w_g / scales) + zeros).round().clamp(0, 15).to(torch.uint8)
+        w_q = w_q.view(K, N)
+
+        scales_2d = scales.squeeze(1).to(torch.bfloat16)
+        zeros_2d = zeros.squeeze(1).to(torch.bfloat16)
+        w_packed = _pack_int4(w_q)
+
+        self.register_buffer("w_q", w_packed)
+        self.register_buffer("scales", scales_2d)
+        self.register_buffer("zeros", zeros_2d)
+
+    def forward(self, x: torch.Tensor) -> torch.Tensor:
+        if self.M == 1 and self.N <= 16384 and self.K == 4096:
+            return _w4a16_small_kernel(x, self.w_q, self.scales, self.zeros,
+                                        self.group_size)
+        return _w4a16_generic_kernel(x, self.w_q, self.scales, self.zeros,
+                                      self.group_size)
+
+
+def _w4a16_small_kernel(x, w_q, scales, zeros, group_size):
+    """Optimized path for small N (up to 16384), typical in LLM shapes.
+
+    Uses a persistent grid where each CTA handles one row of x.
+    """
+    import triton
+    import triton.language as tl
+
+    M, K = x.shape
+    N = w_q.shape[1]
+    n_groups = K // group_size
+    GROUP = group_size
+    BLOCK_N = 128
+
+    grid = (M,)
+
+    @triton.jit
+    def kernel(
+        x_ptr, w_q_ptr, scales_ptr, zeros_ptr,
+        y_ptr,
+        M, N, K,
+        stride_xm, stride_xk,
+        stride_wqn, stride_wq2n,
+        stride_sn, stride_zn,
+        stride_ym, stride_yn,
+        GROUP, BLOCK_N,
+    ):
+        pid_m = tl.program_id(0)
+
+        y_base = y_ptr + pid_m * stride_ym
+
+        acc = tl.zeros((BLOCK_N,), dtype=tl.float32)
+
+        for g in range(GROUP):
+            group_idx = g // GROUP
+            k_start = g
+            k_end = g + 1
+
+            x_row_ptrs = x_ptr + pid_m * stride_xm + tl.arange(0, GROUP) * stride_xk
+            x_vals = tl.load(x_row_ptrs, mask=x_row_ptrs < x_ptr + M * stride_xm * K, other=0.0)
+            x_vals = x_vals.to(tl.float32)
+
+            scale_ptrs = scales_ptr + group_idx * stride_sn + tl.arange(0, BLOCK_N)
+            scale_vals = tl.load(scale_ptrs, mask=scale_ptrs < scales_ptr + n_groups * N, other=0.0)
+            scale_vals = scale_vals.to(tl.float32)
+
+            zero_ptrs = zeros_ptr + group_idx * stride_zn + tl.arange(0, BLOCK_N)
+            zero_vals = tl.load(zero_ptrs, mask=zero_ptrs < zeros_ptr + n_groups * N, other=0.0)
+            zero_vals = zero_vals.to(tl.float32)
+
+            w_lo_ptrs = w_q_ptr + (k_start // 2) * stride_wq2n + tl.arange(0, BLOCK_N)
+            w_hi_ptrs = w_q_ptr + (k_end // 2) * stride_wq2n + tl.arange(0, BLOCK_N)
+
+            w_lo_vals = tl.load(w_lo_ptrs, mask=w_lo_vals < w_q_ptr + (K//2) * N, other=0).to(tl.int32)
+            w_hi_vals = tl.load(w_hi_ptrs, mask=w_hi_vals < w_q_ptr + (K//2) * N, other=0).to(tl.int32)
+
+            w_lo = (w_lo_vals & 0xF).to(tl.float32)
+            w_hi = ((w_hi_vals >> 4) & 0xF).to(tl.float32)
+
+            w_dq_lo = (w_lo - zero_vals) * scale_vals
+            w_dq_hi = (w_hi - zero_vals) * scale_vals
+
+            acc = tl.dot(x_vals, w_dq_lo, acc)
+            acc = tl.dot(x_vals, w_dq_hi, acc)
+
+        y_ptrs = y_base + tl.arange(0, BLOCK_N) * stride_yn
+        tl.store(y_ptrs, acc.to(tl.bfloat16), mask=y_ptrs < y_base + N * stride_yn)
+
+    y = torch.empty((M, N), dtype=torch.bfloat16, device=x.device)
+    stride_xm, stride_xk = x.stride()
+    stride_wqn, stride_wq2n = w_q.stride()
+    stride_sn, stride_zn = scales.stride(), zeros.stride()
+    stride_ym, stride_yn = y.stride()
+
+    kernel[g

... (3383 more chars)
args
{
  "content": "<9000 chars \u2014 see diff>",
  "filePath": "/home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py"
}
tool
stdout (24 chars)
Wrote file successfully.
assistant
Now I'll write the solution. Based on my analysis: - SM120 (Blackwell) has `mma.m16n8k128` for integer mixed-precision MMA - Need to fuse int4 unpacking with the GEMM to avoid memory waste - Triton is available (v3.6.0) and gives us good control
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bash
args
{
  "command": "cd /home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm && python check.py 2>&1",
  "description": "Run check.py correctness tests",
  "timeout": 120000
}
tool
stdout (4333 chars) — TRUNCATED
Traceback (most recent call last):
  File "/home/infatoshi/.local/lib/python3.12/site-packages/triton/language/core.py", line 43, in wrapper
    return fn(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^
  File "/home/infatoshi/.local/lib/python3.12/site-packages/triton/language/core.py", line 1683, in full
    shape = _shape_check_impl(shape)
            ^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/infatoshi/.local/lib/python3.12/site-packages/triton/language/core.py", line 1667, in _shape_check_impl
    validate_block_shape(shape)
  File "/home/infatoshi/.local/lib/python3.12/site-packages/triton/_utils.py", line 52, in validate_block_shape
    raise TypeError(f"Shape element {i} must have type `constexpr[int]`, got `constexpr[{type(d)}]")
TypeError: Shape element 0 must have type `constexpr[int]`, got `constexpr[<class 'triton.language.core.tensor'>]

The above exception was the direct cause of the following exception:

triton.compiler.errors.CompilationError: at 10:11:
def zeros(shape, dtype):
    """
    Returns a tensor filled with the scalar value 0 for the given :code:`shape` and :code:`dtype`.

    :param shape: Shape of the new array, e.g., (8, 16) or (8, )
    :type shape: tuple of ints
    :param dtype: Data-type of the new array, e.g., :code:`tl.float16`
    :type dtype: DType
    """
    return core.full(shape, 0, dtype)
           ^
Shape element 0 must have type `constexpr[int]`, got `constexpr[<class 'triton.language.core.tensor'>]

The above exception was the direc

... (2833 more chars)
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read /home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
args
{
  "filePath": "/home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py",
  "limit": 100,
  "offset": 115
}
tool
stdout (4120 chars) — TRUNCATED
<path>/home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py</path>
<type>file</type>
<content>
115:         acc = tl.zeros((BLOCK_N,), dtype=tl.float32)
116: 
117:         for g in range(GROUP):
118:             group_idx = g // GROUP
119:             k_start = g
120:             k_end = g + 1
121: 
122:             x_row_ptrs = x_ptr + pid_m * stride_xm + tl.arange(0, GROUP) * stride_xk
123:             x_vals = tl.load(x_row_ptrs, mask=x_row_ptrs < x_ptr + M * stride_xm * K, other=0.0)
124:             x_vals = x_vals.to(tl.float32)
125: 
126:             scale_ptrs = scales_ptr + group_idx * stride_sn + tl.arange(0, BLOCK_N)
127:             scale_vals = tl.load(scale_ptrs, mask=scale_ptrs < scales_ptr + n_groups * N, other=0.0)
128:             scale_vals = scale_vals.to(tl.float32)
129: 
130:             zero_ptrs = zeros_ptr + group_idx * stride_zn + tl.arange(0, BLOCK_N)
131:             zero_vals = tl.load(zero_ptrs, mask=zero_ptrs < zeros_ptr + n_groups * N, other=0.0)
132:             zero_vals = zero_vals.to(tl.float32)
133: 
134:             w_lo_ptrs = w_q_ptr + (k_start // 2) * stride_wq2n + tl.arange(0, BLOCK_N)
135:             w_hi_ptrs = w_q_ptr + (k_end // 2) * stride_wq2n + tl.arange(0, BLOCK_N)
136: 
137:             w_lo_vals = tl.load(w_lo_ptrs, mask=w_lo_vals < w_q_ptr + (K//2) * N, other=0).to(tl.int32)
138:             w_hi_vals = tl.load(w_hi_ptrs, mask=w_hi_vals < w_q_ptr + (K//2) * N, other=0).to(tl.int32)
139: 
140:            

... (2620 more chars)
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in 1226out 59cache_r 57888cache_w 0
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write /home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
diff (254 lines — TRUNCATED)
--- a//home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
+++ b//home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
@@ -16,10 +16,6 @@
 
 
 def _pack_int4(w_q: torch.Tensor) -> torch.Tensor:
-    """Pack (K, N) uint8 in [0,15] into (K//2, N) uint8.
-
-    Even rows go in the low nibble, odd rows in the high nibble.
-    """
     K, N = w_q.shape
     assert K % 2 == 0
     lo = w_q[0::2].to(torch.uint8) & 0xF
@@ -28,7 +24,6 @@
 
 
 def _unpack_int4(w_packed: torch.Tensor, K: int) -> torch.Tensor:
-    """Unpack (K//2, N) uint8 -> (K, N) uint8 in [0,15]."""
     Kh, N = w_packed.shape
     assert Kh * 2 == K
     out = torch.empty((K, N), dtype=torch.uint8, device=w_packed.device)
@@ -38,18 +33,10 @@
 
 
 class Model(nn.Module):
-    """W4A16 GEMM: y = x @ dequant(w_q, scales, zeros).
-
-    Uses Triton with a persistent block-kernel approach.
-    Each program instance handles one row of x (M dimension) and loops over K
-    in GROUP_SIZE tiles, dequantizing int4 on-the-fly and accumulating into the
-    bf16 output without materializing a full (K, N) bf16 weight matrix.
-    """
-
     def __init__(self, M: int, N: int, K: int, group_size: int = GROUP_SIZE):
         super().__init__()
-        assert K % group_size == 0, "K must be divisible by group_size"
-        assert K % 2 == 0, "K must be even (int4 packing)"
+        assert K % group_size == 0
+        assert K % 2 == 0
         self.M, self.N, self.K = M, N, K
         self.group_size = group_size
         n_groups = K // group_size
@@ -74,113 +61,19 @@
         self.register_buffer("zeros", zeros_2d)
 
     def forward(self, x: torch.Tensor) -> torch.Tensor:
-        if self.M == 1 and self.N <= 16384 and self.K == 4096:
-            return _w4a16_small_kernel(x, self.w_q, self.scales, self.zeros,
-                                        self.group_size)
-        return _w4a16_generic_kernel(x, self.w_q, self.scales, self.zeros,
-                                      self.group_size)
+        return _w4a16_kernel(x, self.w_q, self.scales, self.zeros,
+                             self.group_size, self.M, self.N, self.K)
 
 
-def _w4a16_small_kernel(x, w_q, scales, zeros, group_size):
-    """Optimized path for small N (up to 16384), typical in LLM shapes.
-
-    Uses a persistent grid where each CTA handles one row of x.
-    """
+def _w4a16_kernel(x, w_q, scales, zeros, group_size, M, N, K):
     import triton
     import triton.language as tl
 
-    M, K = x.shape
-    N = w_q.shape[1]
-    n_groups = K // group_size
-    GROUP = group_size
-    BLOCK_N = 128
-
-    grid = (M,)
-
-    @triton.jit
-    def kernel(
-        x_ptr, w_q_ptr, scales_ptr, zeros_ptr,
-        y_ptr,
-        M, N, K,
-        stride_xm, stride_xk,
-        stride_wqn, stride_wq2n,
-        stride_sn, stride_zn,
-        stride_ym, stride_yn,
-        GROUP, BLOCK_N,
-    ):
-        pid_m = tl.program_id(0)
-
-        y_base = y_ptr + pid_m * stride_ym
-
-        acc = tl.zeros((BLOCK_N,), dtype=tl.float32)
-
-        for g in range(GROUP):
-            group_idx = g // GROUP
-            k_start = g
-            k_end = g + 1
-
-            x_row_ptrs = x_ptr + pid_m * stride_xm + tl.arange(0, GROUP) * stride_xk
-            x_vals = tl.load(x_row_ptrs, mask=x_row_ptrs < x_ptr + M * stride_xm * K, other=0.0)
-            x_vals = x_vals.to(tl.float32)
-
-            scale_ptrs = scales_ptr + group_idx * stride_sn + tl.arange(0, BLOCK_N)
-            scale_vals = tl.load(scale_ptrs, mask=scale_ptrs < scales_ptr + n_groups * N, other=0.0)
-            scale_vals = scale_vals.to(tl.float32)
-
-            zero_ptrs = zeros_ptr + group_idx * stride_zn + tl.arange(0, BLOCK_N)
-            zero_vals = tl.load(zero_ptrs, mask=zero_ptrs < zeros_ptr + n_groups * N, other=0.0)
-            zero_vals = zero_vals.to(tl.float32)
-
-            w_lo_ptrs = w_q_ptr + (k_start // 2) * stride_wq2n + tl.arange(0, BLOCK_N)
-            w_hi_ptrs = w_q_ptr + (k_end // 2) * stride_wq2n + tl.arange(0, BLOCK_N)
-
-            w_lo_vals = tl.load(w_lo_ptrs, mask=w_lo_vals < w_q_ptr + (K//2) * N, other=0).to(tl.int32)
-            w_hi_vals = tl.load(w_hi_ptrs, mask=w_hi_vals < w_q_ptr + (K//2) * N, other=0).to(tl.int32)
-
-            w_lo = (w_lo_vals & 0xF).to(tl.float32)
-            w_hi = ((w_hi_vals >> 4) & 0xF).to(tl.float32)
-
-            w_dq_lo = (w_lo - zero_vals) * scale_vals
-            w_dq_hi = (w_hi - zero_vals) * scale_vals
-
-            acc = tl.dot(x_vals, w_dq_lo, acc)
-            acc = tl.dot(x_vals, w_dq_hi, acc)
-
-        y_ptrs = y_base + tl.arange(0, BLOCK_N) * stride_yn
-        tl.store(y_ptrs, acc.to(tl.bfloat16), mask=y_ptrs < y_base + N * stride_yn)
-
-    y = torch.empty((M, N), dtype=torch.bfloat16, device=x.device)
-    stride_xm, stride_xk = x.stride()
-    stride_wqn, stride_wq2n = w_q.stride()
-    stride_sn, stride_zn = scales.stride(), zeros.stride()
-    stride_ym, stride_yn = y.stride()
-
-    kernel[grid](
-        x, w_q, scales, zeros, y,
-        M, N, K,
-        stride_xm, stride_xk,
-        stride_wqn, stride_wq2n,
-        stride_sn, stride_zn,
-        stride_ym, stride_yn,
-        GROUP, BLOCK_N,
-    )
-    return y
-
-
-def _w4a16_generic_kernel(x, w_q, scales, zeros, group_size):
-    """Generic path using block-level reduction.
-
-    Uses atomics so any block size works for arbitrary M/N.
-    """
-    import triton
-    import triton.language as tl
-
-    M, K = x.shape
-    N = w_q.shape[1]
     n_groups = K // group_size
     GROUP = group_size
     BLOCK_N = 128
     num_warps = 4
+    num_stages = 1
 
     grid = (M, (N + BLOCK_N - 1) // BLOCK_N)
 
@@ -193,50 +86,50 @@
         stride_wq2n,
         stride_sn, stride_zn,
         stride_ym, stride_yn,
-        GROUP, BLOCK_N,
+        n_groups_val,
     ):
         pid_m = tl.program_id(0)
         pid_n = tl.program_id(1)
 
-        y_base = y_ptr + pid_m * stride_ym + pid_n * BLOCK_N * stride_yn
-
         n_off

... (3443 more chars)
args
{
  "content": "<5130 chars \u2014 see diff>",
  "filePath": "/home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py"
}
tool
stdout (24 chars)
Wrote file successfully.
assistant
in 1456out 1743cache_r 59104cache_w 0
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write /home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
diff (59 lines)
--- a//home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
+++ b//home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
@@ -83,7 +83,7 @@
         y_ptr,
         M, N, K,
         stride_xm, stride_xk,
-        stride_wq2n,
+        stride_wqn,
         stride_sn, stride_zn,
         stride_ym, stride_yn,
         n_groups_val,
@@ -100,7 +100,7 @@
 
         for g_idx in range(n_groups_val):
             k_start = g_idx * GROUP
-            k_end = k_start + GROUP
+            k_row_packed = k_start // 2
 
             x_row_ptrs = x_ptr + pid_m * stride_xm + tl.arange(0, GROUP) * stride_xk
             x_mask = (pid_m * stride_xm + tl.arange(0, GROUP) * stride_xk) < (M * stride_xm * K)
@@ -112,16 +112,11 @@
             zero_ptrs = zeros_ptr + g_idx * stride_zn + n_offset
             zero_vals = tl.load(zero_ptrs, mask=n_mask, other=0.0).to(tl.float32)
 
-            w_base = w_q_ptr + n_offset * stride_wq2n
+            w_row_ptr = w_q_ptr + k_row_packed * stride_wqn + n_offset
+            w_vals = tl.load(w_row_ptr, mask=n_mask, other=0).to(tl.int32)
 
-            w_even_ptr = w_base + (k_start // 2) * K // 2 * stride_wq2n
-            w_odd_ptr = w_base + (k_end // 2) * K // 2 * stride_wq2n
-
-            w_even_vals = tl.load(w_even_ptr, mask=n_mask, other=0).to(tl.int32)
-            w_odd_vals = tl.load(w_odd_ptr, mask=n_mask, other=0).to(tl.int32)
-
-            w_even = (w_even_vals & 0xF).to(tl.float32)
-            w_odd = ((w_odd_vals >> 4) & 0xF).to(tl.float32)
+            w_even = (w_vals & 0xF).to(tl.float32)
+            w_odd = ((w_vals >> 4) & 0xF).to(tl.float32)
 
             w_dq_even = (w_even - zero_vals) * scale_vals
             w_dq_odd = (w_odd - zero_vals) * scale_vals
@@ -133,7 +128,7 @@
 
     y = torch.empty((M, N), dtype=torch.bfloat16, device=x.device)
     stride_xm, stride_xk = x.stride()
-    stride_wq2n = w_q.stride(1)
+    stride_wqn = w_q.stride(0)
     stride_sn, stride_zn = scales.stride(1), zeros.stride(1)
     stride_ym, stride_yn = y.stride()
 
@@ -141,7 +136,7 @@
         x, w_q, scales, zeros, y,
         M, N, K,
         stride_xm, stride_xk,
-        stride_wq2n,
+        stride_wqn,
         stride_sn, stride_zn,
         stride_ym, stride_yn,
         n_groups,
args
{
  "content": "<4911 chars \u2014 see diff>",
  "filePath": "/home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py"
}
tool
stdout (24 chars)
Wrote file successfully.
assistant
in 1784out 1715cache_r 60544cache_w 0
assistant
bash
args
{
  "command": "cd /home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm && python check.py 2>&1",
  "description": "Run check.py correctness tests",
  "timeout": 120000
}
tool
stdout (3233 chars) — TRUNCATED
Traceback (most recent call last):
  File "/home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/check.py", line 112, in <module>
    main()
  File "/home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/check.py", line 73, in main
    sol_out = sol_model(*inputs)
              ^^^^^^^^^^^^^^^^^^
  File "/home/infatoshi/.local/lib/python3.12/site-packages/torch/nn/modules/module.py", line 1779, in _wrapped_call_impl
    return self._call_impl(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/infatoshi/.local/lib/python3.12/site-packages/torch/nn/modules/module.py", line 1790, in _call_impl
    return forward_call(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py", line 64, in forward
    return _w4a16_kernel(x, self.w_q, self.scales, self.zeros,
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py", line 135, in _w4a16_kernel
    kernel[grid](
  File "/home/infatoshi/.local/lib/python3.12/site-packages/triton/runtime/jit.py", line 370, in <lambda>
    return lambda *args, **kwargs: self.run(grid=grid, warmup=False, *args, **kwargs)
                                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/infatoshi/.local/lib/python3.12/site-packages/triton/runtime/jit.py", line 720, in run
    kernel = self._do_compile(key, signature, d

... (1733 more chars)
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in 1703out 78cache_r 62304cache_w 0
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edit /home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
diff (10 lines)
--- a//home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
+++ b//home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
@@ -74,6 +74,7 @@
     BLOCK_N = 128
     num_warps = 4
     num_stages = 1
+    BLOCK_N_VAL = BLOCK_N
 
     grid = (M, (N + BLOCK_N - 1) // BLOCK_N)
 
args
{
  "filePath": "/home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py",
  "newString": "<126 chars \u2014 see below>",
  "oldString": "<100 chars \u2014 see below>"
}
newString (126 chars)
    BLOCK_N = 128
    num_warps = 4
    num_stages = 1
    BLOCK_N_VAL = BLOCK_N

    grid = (M, (N + BLOCK_N - 1) // BLOCK_N)
oldString (100 chars)
    BLOCK_N = 128
    num_warps = 4
    num_stages = 1

    grid = (M, (N + BLOCK_N - 1) // BLOCK_N)
tool
stdout (26 chars)
Edit applied successfully.
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in 916out 159cache_r 64000cache_w 0
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edit /home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
diff (19 lines)
--- a//home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
+++ b//home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
@@ -88,6 +88,7 @@
         stride_sn, stride_zn,
         stride_ym, stride_yn,
         n_groups_val,
+        BLOCK_N: tl.constexpr,
     ):
         pid_m = tl.program_id(0)
         pid_n = tl.program_id(1)
@@ -100,7 +101,7 @@
         acc = tl.zeros((BLOCK_N,), dtype=tl.float32)
 
         for g_idx in range(n_groups_val):
-            k_start = g_idx * GROUP
+            k_start = g_idx * BLOCK_N
             k_row_packed = k_start // 2
 
             x_row_ptrs = x_ptr + pid_m * stride_xm + tl.arange(0, GROUP) * stride_xk
args
{
  "filePath": "/home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py",
  "newString": "<638 chars \u2014 see below>",
  "oldString": "<605 chars \u2014 see below>"
}
newString (638 chars)
    @triton.jit
    def kernel(
        x_ptr, w_q_ptr, scales_ptr, zeros_ptr,
        y_ptr,
        M, N, K,
        stride_xm, stride_xk,
        stride_wqn,
        stride_sn, stride_zn,
        stride_ym, stride_yn,
        n_groups_val,
        BLOCK_N: tl.constexpr,
    ):
        pid_m = tl.program_id(0)
        pid_n = tl.program_id(1)

        n_offset = pid_n * BLOCK_N + tl.arange(0, BLOCK_N)
        n_mask = n_offset < N

        y_base = y_ptr + pid_m * stride_ym + n_offset * stride_yn

        acc = tl.zeros((BLOCK_N,), dtype=tl.float32)

        for g_idx in range(n_groups_val):
            k_start = g_idx * BLOCK_N
oldString (605 chars)
    @triton.jit
    def kernel(
        x_ptr, w_q_ptr, scales_ptr, zeros_ptr,
        y_ptr,
        M, N, K,
        stride_xm, stride_xk,
        stride_wqn,
        stride_sn, stride_zn,
        stride_ym, stride_yn,
        n_groups_val,
    ):
        pid_m = tl.program_id(0)
        pid_n = tl.program_id(1)

        n_offset = pid_n * BLOCK_N + tl.arange(0, BLOCK_N)
        n_mask = n_offset < N

        y_base = y_ptr + pid_m * stride_ym + n_offset * stride_yn

        acc = tl.zeros((BLOCK_N,), dtype=tl.float32)

        for g_idx in range(n_groups_val):
            k_start = g_idx * GROUP
tool
stdout (26 chars)
Edit applied successfully.
assistant
in 197out 422cache_r 64896cache_w 0
assistant
edit /home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
diff (11 lines)
--- a//home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
+++ b//home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
@@ -101,7 +101,7 @@
         acc = tl.zeros((BLOCK_N,), dtype=tl.float32)
 
         for g_idx in range(n_groups_val):
-            k_start = g_idx * BLOCK_N
+            k_start = g_idx * GROUP
             k_row_packed = k_start // 2
 
             x_row_ptrs = x_ptr + pid_m * stride_xm + tl.arange(0, GROUP) * stride_xk
args
{
  "filePath": "/home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py",
  "newString": "            k_start = g_idx * GROUP",
  "oldString": "            k_start = g_idx * BLOCK_N"
}
tool
stdout (26 chars)
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read /home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
args
{
  "filePath": "/home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py",
  "limit": 25,
  "offset": 125
}
tool
stdout (982 chars)
<path>/home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py</path>
<type>file</type>
<content>
125: 
126:             acc = tl.dot(x_vals, w_dq_even, acc)
127:             acc = tl.dot(x_vals, w_dq_odd, acc)
128: 
129:         tl.store(y_base, acc.to(tl.bfloat16), mask=n_mask)
130: 
131:     y = torch.empty((M, N), dtype=torch.bfloat16, device=x.device)
132:     stride_xm, stride_xk = x.stride()
133:     stride_wqn = w_q.stride(0)
134:     stride_sn, stride_zn = scales.stride(1), zeros.stride(1)
135:     stride_ym, stride_yn = y.stride()
136: 
137:     kernel[grid](
138:         x, w_q, scales, zeros, y,
139:         M, N, K,
140:         stride_xm, stride_xk,
141:         stride_wqn,
142:         stride_sn, stride_zn,
143:         stride_ym, stride_yn,
144:         n_groups,
145:         num_warps=num_warps,
146:         num_stages=num_stages,
147:     )
148:     return y
149: 

(Showing lines 125-149 of 162. Use offset=150 to continue.)
</content>
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edit /home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
diff (10 lines)
--- a//home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
+++ b//home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
@@ -142,6 +142,7 @@
         stride_sn, stride_zn,
         stride_ym, stride_yn,
         n_groups,
+        BLOCK_N_VAL,
         num_warps=num_warps,
         num_stages=num_stages,
     )
args
{
  "filePath": "/home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py",
  "newString": "<283 chars \u2014 see below>",
  "oldString": "<262 chars \u2014 see below>"
}
newString (283 chars)
    kernel[grid](
        x, w_q, scales, zeros, y,
        M, N, K,
        stride_xm, stride_xk,
        stride_wqn,
        stride_sn, stride_zn,
        stride_ym, stride_yn,
        n_groups,
        BLOCK_N_VAL,
        num_warps=num_warps,
        num_stages=num_stages,
    )
oldString (262 chars)
    kernel[grid](
        x, w_q, scales, zeros, y,
        M, N, K,
        stride_xm, stride_xk,
        stride_wqn,
        stride_sn, stride_zn,
        stride_ym, stride_yn,
        n_groups,
        num_warps=num_warps,
        num_stages=num_stages,
    )
tool
stdout (26 chars)
Edit applied successfully.
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edit /home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
args
{
  "filePath": "/home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py",
  "newString": "<257 chars \u2014 see below>",
  "oldString": "<257 chars \u2014 see below>"
}
newString (257 chars)
        acc = tl.zeros((BLOCK_N,), dtype=tl.float32)

        for g_idx in range(n_groups_val):
            k_start = g_idx * GROUP
            k_row_packed = k_start // 2

            x_row_ptrs = x_ptr + pid_m * stride_xm + tl.arange(0, GROUP) * stride_xk
oldString (257 chars)
        acc = tl.zeros((BLOCK_N,), dtype=tl.float32)

        for g_idx in range(n_groups_val):
            k_start = g_idx * GROUP
            k_row_packed = k_start // 2

            x_row_ptrs = x_ptr + pid_m * stride_xm + tl.arange(0, GROUP) * stride_xk
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edit /home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
diff (10 lines)
--- a//home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
+++ b//home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
@@ -88,6 +88,7 @@
         stride_sn, stride_zn,
         stride_ym, stride_yn,
         n_groups_val,
+        GROUP: tl.constexpr,
         BLOCK_N: tl.constexpr,
     ):
         pid_m = tl.program_id(0)
args
{
  "filePath": "/home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py",
  "newString": "<791 chars \u2014 see below>",
  "oldString": "<762 chars \u2014 see below>"
}
newString (791 chars)
    @triton.jit
    def kernel(
        x_ptr, w_q_ptr, scales_ptr, zeros_ptr,
        y_ptr,
        M, N, K,
        stride_xm, stride_xk,
        stride_wqn,
        stride_sn, stride_zn,
        stride_ym, stride_yn,
        n_groups_val,
        GROUP: tl.constexpr,
        BLOCK_N: tl.constexpr,
    ):
        pid_m = tl.program_id(0)
        pid_n = tl.program_id(1)

        n_offset = pid_n * BLOCK_N + tl.arange(0, BLOCK_N)
        n_mask = n_offset < N

        y_base = y_ptr + pid_m * stride_ym + n_offset * stride_yn

        acc = tl.zeros((BLOCK_N,), dtype=tl.float32)

        for g_idx in range(n_groups_val):
            k_start = g_idx * GROUP
            k_row_packed = k_start // 2

            x_row_ptrs = x_ptr + pid_m * stride_xm + tl.arange(0, GROUP) * stride_xk
oldString (762 chars)
    @triton.jit
    def kernel(
        x_ptr, w_q_ptr, scales_ptr, zeros_ptr,
        y_ptr,
        M, N, K,
        stride_xm, stride_xk,
        stride_wqn,
        stride_sn, stride_zn,
        stride_ym, stride_yn,
        n_groups_val,
        BLOCK_N: tl.constexpr,
    ):
        pid_m = tl.program_id(0)
        pid_n = tl.program_id(1)

        n_offset = pid_n * BLOCK_N + tl.arange(0, BLOCK_N)
        n_mask = n_offset < N

        y_base = y_ptr + pid_m * stride_ym + n_offset * stride_yn

        acc = tl.zeros((BLOCK_N,), dtype=tl.float32)

        for g_idx in range(n_groups_val):
            k_start = g_idx * GROUP
            k_row_packed = k_start // 2

            x_row_ptrs = x_ptr + pid_m * stride_xm + tl.arange(0, GROUP) * stride_xk
tool
stdout (26 chars)
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edit /home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
diff (10 lines)
--- a//home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
+++ b//home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
@@ -143,6 +143,7 @@
         stride_sn, stride_zn,
         stride_ym, stride_yn,
         n_groups,
+        GROUP,
         BLOCK_N_VAL,
         num_warps=num_warps,
         num_stages=num_stages,
args
{
  "filePath": "/home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py",
  "newString": "<298 chars \u2014 see below>",
  "oldString": "<283 chars \u2014 see below>"
}
newString (298 chars)
    kernel[grid](
        x, w_q, scales, zeros, y,
        M, N, K,
        stride_xm, stride_xk,
        stride_wqn,
        stride_sn, stride_zn,
        stride_ym, stride_yn,
        n_groups,
        GROUP,
        BLOCK_N_VAL,
        num_warps=num_warps,
        num_stages=num_stages,
    )
oldString (283 chars)
    kernel[grid](
        x, w_q, scales, zeros, y,
        M, N, K,
        stride_xm, stride_xk,
        stride_wqn,
        stride_sn, stride_zn,
        stride_ym, stride_yn,
        n_groups,
        BLOCK_N_VAL,
        num_warps=num_warps,
        num_stages=num_stages,
    )
tool
stdout (26 chars)
Edit applied successfully.
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write /home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
diff (213 lines — TRUNCATED)
--- a//home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
+++ b//home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
@@ -1,4 +1,4 @@
-"""Fused W4A16 GEMM — Triton kernel, AWQ/GPTQ-style asymmetric int4.
+"""Fused W4A16 GEMM — CUDA C++ via load_inline, AWQ/GPTQ-style asymmetric int4.
 
 Dequantizes on-the-fly: (w_q[k,n] - zeros[g,n]) * scales[g,n] with group=128
 along K. Two int4 weights are packed per uint8 byte (low nibble=even, high=odd).
@@ -7,6 +7,7 @@
 
 import torch
 import torch.nn as nn
+import torch.utils.cpp_extension
 
 OP_TYPE = "gemm_w4a16"
 SUPPORTED_PRECISIONS = ["int4_bf16"]
@@ -30,6 +31,64 @@
     out[0::2] = w_packed & 0xF
     out[1::2] = (w_packed >> 4) & 0xF
     return out
+
+
+cuda_source = r"""
+extern "C" __global__
+void w4a16_kernel(
+    const __nhalf* __restrict__ x,     // (M, K) bf16
+    const __uint8_t* __restrict__ w_q,  // (K/2, N) packed int4
+    const __nhalf* __restrict__ scales, // (n_groups, N) bf16
+    const __nhalf* __restrict__ zeros,  // (n_groups, N) bf16
+    __nhalf* __restrict__ y,            // (M, N) bf16 output
+    int M, int N, int K, int n_groups
+) {
+    int n = blockIdx.x * blockDim.x + threadIdx.x;
+    int m = blockIdx.y;
+
+    if (n >= N || m >= M) return;
+
+    float acc = 0.0f;
+
+    for (int g = 0; g < n_groups; ++g) {
+        int k_base = g * 128;
+
+        // Load scale and zero for this group (same for all k in group)
+        __nhalf sc = scales[g * N + n];
+        __nhalf ze = zeros[g * N + n];
+        float scale = __half2float(sc);
+        float zero = __half2float(ze);
+
+        // Process 128 k values (64 packed bytes per row of w_q)
+        for (int kk = 0; kk < 128; kk += 2) {
+            int k_even = k_base + kk;
+            int k_odd = k_base + kk + 1;
+            int w_row = k_even / 2;
+
+            uint8_t w packed = w_q[w_row * N + n];
+            uint8_t w_even_val = w_packed & 0xF;
+            uint8_t w_odd_val = (wPacked >> 4) & 0xF;
+
+            __nhalf x_even = x[m * K + k_even];
+            __nhalf x_odd = x[m * K + k_odd];
+
+            float w_even = (float)w_even_val;
+            float w_odd = (float)w_odd_val;
+
+            float w_deq_even = (w_even - zero) * scale;
+            float w_deq_odd = (w_odd - zero) * scale;
+
+            float xf_even = __half2float(x_even);
+            float xf_odd = __half2float(x_odd);
+
+            acc += xf_even * w_deq_even;
+            acc += xf_odd * w_deq_odd;
+        }
+    }
+
+    y[m * N + n] = __float2half(acc);
+}
+"""
 
 
 class Model(nn.Module):
@@ -61,94 +120,28 @@
         self.register_buffer("zeros", zeros_2d)
 
     def forward(self, x: torch.Tensor) -> torch.Tensor:
-        return _w4a16_kernel(x, self.w_q, self.scales, self.zeros,
-                             self.group_size, self.M, self.N, self.K)
+        M, K = x.shape
+        N = self.N
+        n_groups = K // self.group_size
 
+        y = torch.empty((M, N), dtype=torch.bfloat16, device=x.device)
 
-def _w4a16_kernel(x, w_q, scales, zeros, group_size, M, N, K):
-    import triton
-    import triton.language as tl
+        block_x = 128
+        block_y = 1
+        grid_x = (N + block_x - 1) // block_x
+        grid_y = M
+        grid_z = 1
 
-    n_groups = K // group_size
-    GROUP = group_size
-    BLOCK_N = 128
-    num_warps = 4
-    num_stages = 1
-    BLOCK_N_VAL = BLOCK_N
+        w4a16_kernel_fused(
+            torch.cuda.current_stream(),
+            [grid_x, grid_y, grid_z],
+            [block_x, block_y, 1],
+            0,
+            x, self.w_q, self.scales, self.zeros, y,
+            M, N, K, n_groups
+        )
 
-    grid = (M, (N + BLOCK_N - 1) // BLOCK_N)
-
-    @triton.jit
-    def kernel(
-        x_ptr, w_q_ptr, scales_ptr, zeros_ptr,
-        y_ptr,
-        M, N, K,
-        stride_xm, stride_xk,
-        stride_wqn,
-        stride_sn, stride_zn,
-        stride_ym, stride_yn,
-        n_groups_val,
-        GROUP: tl.constexpr,
-        BLOCK_N: tl.constexpr,
-    ):
-        pid_m = tl.program_id(0)
-        pid_n = tl.program_id(1)
-
-        n_offset = pid_n * BLOCK_N + tl.arange(0, BLOCK_N)
-        n_mask = n_offset < N
-
-        y_base = y_ptr + pid_m * stride_ym + n_offset * stride_yn
-
-        acc = tl.zeros((BLOCK_N,), dtype=tl.float32)
-
-        for g_idx in range(n_groups_val):
-            k_start = g_idx * GROUP
-            k_row_packed = k_start // 2
-
-            x_row_ptrs = x_ptr + pid_m * stride_xm + tl.arange(0, GROUP) * stride_xk
-            x_mask = (pid_m * stride_xm + tl.arange(0, GROUP) * stride_xk) < (M * stride_xm * K)
-            x_vals = tl.load(x_row_ptrs, mask=x_mask, other=0.0).to(tl.float32)
-
-            scale_ptrs = scales_ptr + g_idx * stride_sn + n_offset
-            scale_vals = tl.load(scale_ptrs, mask=n_mask, other=0.0).to(tl.float32)
-
-            zero_ptrs = zeros_ptr + g_idx * stride_zn + n_offset
-            zero_vals = tl.load(zero_ptrs, mask=n_mask, other=0.0).to(tl.float32)
-
-            w_row_ptr = w_q_ptr + k_row_packed * stride_wqn + n_offset
-            w_vals = tl.load(w_row_ptr, mask=n_mask, other=0).to(tl.int32)
-
-            w_even = (w_vals & 0xF).to(tl.float32)
-            w_odd = ((w_vals >> 4) & 0xF).to(tl.float32)
-
-            w_dq_even = (w_even - zero_vals) * scale_vals
-            w_dq_odd = (w_odd - zero_vals) * scale_vals
-
-            acc = tl.dot(x_vals, w_dq_even, acc)
-            acc = tl.dot(x_vals, w_dq_odd, acc)
-
-        tl.store(y_base, acc.to(tl.bfloat16), mask=n_mask)
-
-    y = torch.empty((M, N), dtype=torch.bfloat16, device=x.device)
-    stride_xm, stride_xk = x.stride()
-    stride_wqn = w_q.stride(0)
-    stride_sn, stride_zn = scales.stride(1), zeros.stride(1)
-    stride_ym, stride_yn = y.stride()
-
-    kernel[grid](
-        x, w_q, scales, zeros, y,
-        M, N, K,
-        stride_xm, stride_xk,
-        stride_wqn,
-        stride_sn, stride_zn,
-        stride_ym, stride_y

... (663 more chars)
args
{
  "content": "<5015 chars \u2014 see diff>",
  "filePath": "/home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py"
}
tool
stdout (24 chars)
Wrote file successfully.
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write /home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
diff (125 lines)
--- a//home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
+++ b//home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
@@ -34,13 +34,14 @@
 
 
 cuda_source = r"""
-extern "C" __global__
+extern "C"
+__global__
 void w4a16_kernel(
-    const __nhalf* __restrict__ x,     // (M, K) bf16
-    const __uint8_t* __restrict__ w_q,  // (K/2, N) packed int4
-    const __nhalf* __restrict__ scales, // (n_groups, N) bf16
-    const __nhalf* __restrict__ zeros,  // (n_groups, N) bf16
-    __nhalf* __restrict__ y,            // (M, N) bf16 output
+    const __nhalf* __restrict__ x,
+    const __uint8_t* __restrict__ w_q,
+    const __nhalf* __restrict__ scales,
+    const __nhalf* __restrict__ zeros,
+    __nhalf* __restrict__ y,
     int M, int N, int K, int n_groups
 ) {
     int n = blockIdx.x * blockDim.x + threadIdx.x;
@@ -52,37 +53,28 @@
 
     for (int g = 0; g < n_groups; ++g) {
         int k_base = g * 128;
-
-        // Load scale and zero for this group (same for all k in group)
         __nhalf sc = scales[g * N + n];
         __nhalf ze = zeros[g * N + n];
         float scale = __half2float(sc);
         float zero = __half2float(ze);
 
-        // Process 128 k values (64 packed bytes per row of w_q)
         for (int kk = 0; kk < 128; kk += 2) {
             int k_even = k_base + kk;
             int k_odd = k_base + kk + 1;
-            int w_row = k_even / 2;
+            int w_row = k_even >> 1;
 
-            uint8_t w packed = w_q[w_row * N + n];
-            uint8_t w_even_val = w_packed & 0xF;
-            uint8_t w_odd_val = (wPacked >> 4) & 0xF;
+            uint8_t w_p = w_q[w_row * N + n];
+            uint8_t w_e = w_p & 0xF;
+            uint8_t w_o = (w_p >> 4) & 0xF;
 
-            __nhalf x_even = x[m * K + k_even];
-            __nhalf x_odd = x[m * K + k_odd];
+            float w_deq_e = ((float)w_e - zero) * scale;
+            float w_deq_o = ((float)w_o - zero) * scale;
 
-            float w_even = (float)w_even_val;
-            float w_odd = (float)w_odd_val;
+            float x_e = __half2float(x[m * K + k_even]);
+            float x_o = __half2float(x[m * K + k_odd]);
 
-            float w_deq_even = (w_even - zero) * scale;
-            float w_deq_odd = (w_odd - zero) * scale;
-
-            float xf_even = __half2float(x_even);
-            float xf_odd = __half2float(x_odd);
-
-            acc += xf_even * w_deq_even;
-            acc += xf_odd * w_deq_odd;
+            acc += x_e * w_deq_e;
+            acc += x_o * w_deq_o;
         }
     }
 
@@ -120,22 +112,21 @@
         self.register_buffer("zeros", zeros_2d)
 
     def forward(self, x: torch.Tensor) -> torch.Tensor:
-        M, K = x.shape
+        M = self.M
         N = self.N
+        K = self.K
         n_groups = K // self.group_size
 
         y = torch.empty((M, N), dtype=torch.bfloat16, device=x.device)
 
-        block_x = 128
-        block_y = 1
-        grid_x = (N + block_x - 1) // block_x
+        BLOCK_N = 128
+        grid_x = (N + BLOCK_N - 1) // BLOCK_N
         grid_y = M
-        grid_z = 1
 
-        w4a16_kernel_fused(
+        w4a16_kernel(
             torch.cuda.current_stream(),
-            [grid_x, grid_y, grid_z],
-            [block_x, block_y, 1],
+            [grid_x, grid_y, 1],
+            [BLOCK_N, 1, 1],
             0,
             x, self.w_q, self.scales, self.zeros, y,
             M, N, K, n_groups
@@ -158,16 +149,10 @@
     return [M, N, K]
 
 
-try:
-    w4a16_kernel_fused = torch.utils.cpp_extension.load_inline(
-        name="w4a16_fused",
-        cpp_source="",
-        cuda_source=cuda_source,
-        extra_cuda_cflags=["--use_fast_math", "-O3"],
-        extra_include_paths=[],
-        is_dynamic=False,
-    )
-except Exception as e:
-    import warnings
-    warnings.warn(f"Could not load CUDA inline kernel: {e}")
-    w4a16_kernel_fused = None
+w4a16_kernel = torch.utils.cpp_extension.load_inline(
+    name="w4a16_fused",
+    cpp_source="",
+    cuda_source=cuda_source,
+    extra_cuda_cflags=["--use_fast_math", "-O3"],
+    is_dynamic=False,
+)
args
{
  "content": "<4304 chars \u2014 see diff>",
  "filePath": "/home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py"
}
tool
stdout (24 chars)
Wrote file successfully.
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args
{
  "command": "cd /home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm && python check.py 2>&1",
  "description": "Run check.py correctness tests",
  "timeout": 120000
}
tool
stdout (82 chars)
FAIL: import error: load_inline() got an unexpected keyword argument 'cpp_source'
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args
{
  "command": "python -c \"import torch.utils.cpp_extension; import inspect; print(inspect.signature(torch.utils.cpp_extension.load_inline))\"",
  "description": "Check load_inline signature"
}
tool
stdout (380 chars)
(name, cpp_sources, cuda_sources=None, sycl_sources=None, functions=None, extra_cflags=None, extra_cuda_cflags=None, extra_sycl_cflags=None, extra_ldflags=None, extra_include_paths=None, build_directory=None, verbose=False, with_cuda=None, with_sycl=None, is_python_module=True, with_pytorch_error_handling=True, keep_intermediates=True, use_pch=False, no_implicit_headers=False)
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edit /home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
diff (13 lines)
--- a//home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
+++ b//home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
@@ -151,8 +151,8 @@
 
 w4a16_kernel = torch.utils.cpp_extension.load_inline(
     name="w4a16_fused",
-    cpp_source="",
-    cuda_source=cuda_source,
+    cpp_sources="",
+    cuda_sources=cuda_source,
     extra_cuda_cflags=["--use_fast_math", "-O3"],
     is_dynamic=False,
 )
args
{
  "filePath": "/home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py",
  "newString": "<201 chars \u2014 see below>",
  "oldString": "<199 chars \u2014 see below>"
}
newString (201 chars)
w4a16_kernel = torch.utils.cpp_extension.load_inline(
    name="w4a16_fused",
    cpp_sources="",
    cuda_sources=cuda_source,
    extra_cuda_cflags=["--use_fast_math", "-O3"],
    is_dynamic=False,
)
oldString (199 chars)
w4a16_kernel = torch.utils.cpp_extension.load_inline(
    name="w4a16_fused",
    cpp_source="",
    cuda_source=cuda_source,
    extra_cuda_cflags=["--use_fast_math", "-O3"],
    is_dynamic=False,
)
tool
stdout (26 chars)
Edit applied successfully.
assistant
in 175out 183cache_r 70656cache_w 0
assistant
bash
args
{
  "command": "cd /home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm && python check.py 2>&1",
  "description": "Run check.py correctness tests",
  "timeout": 180000
}
tool
stdout (82 chars)
FAIL: import error: load_inline() got an unexpected keyword argument 'is_dynamic'
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assistant
edit /home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
diff (8 lines)
--- a//home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
+++ b//home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
@@ -154,5 +154,4 @@
     cpp_sources="",
     cuda_sources=cuda_source,
     extra_cuda_cflags=["--use_fast_math", "-O3"],
-    is_dynamic=False,
 )
args
{
  "filePath": "/home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py",
  "newString": "<179 chars \u2014 see below>",
  "oldString": "<201 chars \u2014 see below>"
}
newString (179 chars)
w4a16_kernel = torch.utils.cpp_extension.load_inline(
    name="w4a16_fused",
    cpp_sources="",
    cuda_sources=cuda_source,
    extra_cuda_cflags=["--use_fast_math", "-O3"],
)
oldString (201 chars)
w4a16_kernel = torch.utils.cpp_extension.load_inline(
    name="w4a16_fused",
    cpp_sources="",
    cuda_sources=cuda_source,
    extra_cuda_cflags=["--use_fast_math", "-O3"],
    is_dynamic=False,
)
tool
stdout (26 chars)
Edit applied successfully.
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in 131out 173cache_r 71008cache_w 0
assistant
bash
args
{
  "command": "cd /home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm && python check.py 2>&1",
  "description": "Run check.py correctness tests",
  "timeout": 180000
}
tool
stdout (3184 chars) — TRUNCATED
FAIL: import error: Error building extension 'w4a16_fused': [1/3] /usr/local/cuda-13/bin/nvcc -MD -MF cuda.cuda.o.d -DTORCH_EXTENSION_NAME=w4a16_fused -DTORCH_API_INCLUDE_EXTENSION_H -isystem /home/infatoshi/.local/lib/python3.12/site-packages/torch/include -isystem /home/infatoshi/.local/lib/python3.12/site-packages/torch/include/torch/csrc/api/include -isystem /usr/local/cuda-13/include -isystem /usr/include/python3.12 -D__CUDA_NO_HALF_OPERATORS__ -D__CUDA_NO_HALF_CONVERSIONS__ -D__CUDA_NO_BFLOAT16_CONVERSIONS__ -D__CUDA_NO_HALF2_OPERATORS__ --expt-relaxed-constexpr -gencode=arch=compute_120,code=compute_120 -gencode=arch=compute_120,code=sm_120 --compiler-options '-fPIC' --use_fast_math -O3 -std=c++17 -c /home/infatoshi/.cache/torch_extensions/py312_cu130/w4a16_fused/cuda.cu -o cuda.cuda.o 
FAILED: cuda.cuda.o 
/usr/local/cuda-13/bin/nvcc -MD -MF cuda.cuda.o.d -DTORCH_EXTENSION_NAME=w4a16_fused -DTORCH_API_INCLUDE_EXTENSION_H -isystem /home/infatoshi/.local/lib/python3.12/site-packages/torch/include -isystem /home/infatoshi/.local/lib/python3.12/site-packages/torch/include/torch/csrc/api/include -isystem /usr/local/cuda-13/include -isystem /usr/include/python3.12 -D__CUDA_NO_HALF_OPERATORS__ -D__CUDA_NO_HALF_CONVERSIONS__ -D__CUDA_NO_BFLOAT16_CONVERSIONS__ -D__CUDA_NO_HALF2_OPERATORS__ --expt-relaxed-constexpr -gencode=arch=compute_120,code=compute_120 -gencode=arch=compute_120,code=sm_120 --compiler-options '-fPIC' --use_fast_math -O3 -std=c++17 -c /home/infatoshi/.cache/

... (1684 more chars)
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edit /home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
diff (48 lines)
--- a//home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
+++ b//home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
@@ -34,14 +34,16 @@
 
 
 cuda_source = r"""
+#include <cuda_fp16.h>
+
 extern "C"
 __global__
 void w4a16_kernel(
-    const __nhalf* __restrict__ x,
-    const __uint8_t* __restrict__ w_q,
-    const __nhalf* __restrict__ scales,
-    const __nhalf* __restrict__ zeros,
-    __nhalf* __restrict__ y,
+    const __half* __restrict__ x,
+    const unsigned char* __restrict__ w_q,
+    const __half* __restrict__ scales,
+    const __half* __restrict__ zeros,
+    __half* __restrict__ y,
     int M, int N, int K, int n_groups
 ) {
     int n = blockIdx.x * blockDim.x + threadIdx.x;
@@ -53,8 +55,8 @@
 
     for (int g = 0; g < n_groups; ++g) {
         int k_base = g * 128;
-        __nhalf sc = scales[g * N + n];
-        __nhalf ze = zeros[g * N + n];
+        __half sc = scales[g * N + n];
+        __half ze = zeros[g * N + n];
         float scale = __half2float(sc);
         float zero = __half2float(ze);
 
@@ -63,9 +65,9 @@
             int k_odd = k_base + kk + 1;
             int w_row = k_even >> 1;
 
-            uint8_t w_p = w_q[w_row * N + n];
-            uint8_t w_e = w_p & 0xF;
-            uint8_t w_o = (w_p >> 4) & 0xF;
+            unsigned char w_p = w_q[w_row * N + n];
+            unsigned char w_e = w_p & 0xF;
+            unsigned char w_o = (w_p >> 4) & 0xF;
 
             float w_deq_e = ((float)w_e - zero) * scale;
             float w_deq_o = ((float)w_o - zero) * scale;
args
{
  "filePath": "/home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py",
  "newString": "<1336 chars \u2014 see below>",
  "oldString": "<1296 chars \u2014 see below>"
}
newString (1336 chars)
cuda_source = r"""
#include <cuda_fp16.h>

extern "C"
__global__
void w4a16_kernel(
    const __half* __restrict__ x,
    const unsigned char* __restrict__ w_q,
    const __half* __restrict__ scales,
    const __half* __restrict__ zeros,
    __half* __restrict__ y,
    int M, int N, int K, int n_groups
) {
    int n = blockIdx.x * blockDim.x + threadIdx.x;
    int m = blockIdx.y;

    if (n >= N || m >= M) return;

    float acc = 0.0f;

    for (int g = 0; g < n_groups; ++g) {
        int k_base = g * 128;
        __half sc = scales[g * N + n];
        __half ze = zeros[g * N + n];
        float scale = __half2float(sc);
        float zero = __half2float(ze);

        for (int kk = 0; kk < 128; kk += 2) {
            int k_even = k_base + kk;
            int k_odd = k_base + kk + 1;
            int w_row = k_even >> 1;

            unsigned char w_p = w_q[w_row * N + n];
            unsigned char w_e = w_p & 0xF;
            unsigned char w_o = (w_p >> 4) & 0xF;

            float w_deq_e = ((float)w_e - zero) * scale;
            float w_deq_o = ((float)w_o - zero) * scale;

            float x_e = __half2float(x[m * K + k_even]);
            float x_o = __half2float(x[m * K + k_odd]);

            acc += x_e * w_deq_e;
            acc += x_o * w_deq_o;
        }
    }

    y[m * N + n] = __float2half(acc);
}
"""
oldString (1296 chars)
cuda_source = r"""
extern "C"
__global__
void w4a16_kernel(
    const __nhalf* __restrict__ x,
    const __uint8_t* __restrict__ w_q,
    const __nhalf* __restrict__ scales,
    const __nhalf* __restrict__ zeros,
    __nhalf* __restrict__ y,
    int M, int N, int K, int n_groups
) {
    int n = blockIdx.x * blockDim.x + threadIdx.x;
    int m = blockIdx.y;

    if (n >= N || m >= M) return;

    float acc = 0.0f;

    for (int g = 0; g < n_groups; ++g) {
        int k_base = g * 128;
        __nhalf sc = scales[g * N + n];
        __nhalf ze = zeros[g * N + n];
        float scale = __half2float(sc);
        float zero = __half2float(ze);

        for (int kk = 0; kk < 128; kk += 2) {
            int k_even = k_base + kk;
            int k_odd = k_base + kk + 1;
            int w_row = k_even >> 1;

            uint8_t w_p = w_q[w_row * N + n];
            uint8_t w_e = w_p & 0xF;
            uint8_t w_o = (w_p >> 4) & 0xF;

            float w_deq_e = ((float)w_e - zero) * scale;
            float w_deq_o = ((float)w_o - zero) * scale;

            float x_e = __half2float(x[m * K + k_even]);
            float x_o = __half2float(x[m * K + k_odd]);

            acc += x_e * w_deq_e;
            acc += x_o * w_deq_o;
        }
    }

    y[m * N + n] = __float2half(acc);
}
"""
tool
stdout (26 chars)
Edit applied successfully.
assistant
in 1112out 955cache_r 71328cache_w 0
assistant
edit /home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
diff (57 lines)
--- a//home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
+++ b//home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
@@ -35,15 +35,16 @@
 
 cuda_source = r"""
 #include <cuda_fp16.h>
+#include <cuda_bf16.h>
 
 extern "C"
 __global__
 void w4a16_kernel(
-    const __half* __restrict__ x,
+    const __nv_bfloat16* __restrict__ x,
     const unsigned char* __restrict__ w_q,
-    const __half* __restrict__ scales,
-    const __half* __restrict__ zeros,
-    __half* __restrict__ y,
+    const __nv_bfloat16* __restrict__ scales,
+    const __nv_bfloat16* __restrict__ zeros,
+    __nv_bfloat16* __restrict__ y,
     int M, int N, int K, int n_groups
 ) {
     int n = blockIdx.x * blockDim.x + threadIdx.x;
@@ -55,10 +56,10 @@
 
     for (int g = 0; g < n_groups; ++g) {
         int k_base = g * 128;
-        __half sc = scales[g * N + n];
-        __half ze = zeros[g * N + n];
-        float scale = __half2float(sc);
-        float zero = __half2float(ze);
+        __nv_bfloat16 sc = scales[g * N + n];
+        __nv_bfloat16 ze = zeros[g * N + n];
+        float scale = __bfloat162float(sc);
+        float zero = __bfloat162float(ze);
 
         for (int kk = 0; kk < 128; kk += 2) {
             int k_even = k_base + kk;
@@ -72,15 +73,15 @@
             float w_deq_e = ((float)w_e - zero) * scale;
             float w_deq_o = ((float)w_o - zero) * scale;
 
-            float x_e = __half2float(x[m * K + k_even]);
-            float x_o = __half2float(x[m * K + k_odd]);
+            float x_e = __bfloat162float(x[m * K + k_even]);
+            float x_o = __bfloat162float(x[m * K + k_odd]);
 
             acc += x_e * w_deq_e;
             acc += x_o * w_deq_o;
         }
     }
 
-    y[m * N + n] = __float2half(acc);
+    y[m * N + n] = __float2bfloat16(acc);
 }
 """
 
args
{
  "filePath": "/home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py",
  "newString": "<1421 chars \u2014 see below>",
  "oldString": "<1336 chars \u2014 see below>"
}
newString (1421 chars)
cuda_source = r"""
#include <cuda_fp16.h>
#include <cuda_bf16.h>

extern "C"
__global__
void w4a16_kernel(
    const __nv_bfloat16* __restrict__ x,
    const unsigned char* __restrict__ w_q,
    const __nv_bfloat16* __restrict__ scales,
    const __nv_bfloat16* __restrict__ zeros,
    __nv_bfloat16* __restrict__ y,
    int M, int N, int K, int n_groups
) {
    int n = blockIdx.x * blockDim.x + threadIdx.x;
    int m = blockIdx.y;

    if (n >= N || m >= M) return;

    float acc = 0.0f;

    for (int g = 0; g < n_groups; ++g) {
        int k_base = g * 128;
        __nv_bfloat16 sc = scales[g * N + n];
        __nv_bfloat16 ze = zeros[g * N + n];
        float scale = __bfloat162float(sc);
        float zero = __bfloat162float(ze);

        for (int kk = 0; kk < 128; kk += 2) {
            int k_even = k_base + kk;
            int k_odd = k_base + kk + 1;
            int w_row = k_even >> 1;

            unsigned char w_p = w_q[w_row * N + n];
            unsigned char w_e = w_p & 0xF;
            unsigned char w_o = (w_p >> 4) & 0xF;

            float w_deq_e = ((float)w_e - zero) * scale;
            float w_deq_o = ((float)w_o - zero) * scale;

            float x_e = __bfloat162float(x[m * K + k_even]);
            float x_o = __bfloat162float(x[m * K + k_odd]);

            acc += x_e * w_deq_e;
            acc += x_o * w_deq_o;
        }
    }

    y[m * N + n] = __float2bfloat16(acc);
}
"""
oldString (1336 chars)
cuda_source = r"""
#include <cuda_fp16.h>

extern "C"
__global__
void w4a16_kernel(
    const __half* __restrict__ x,
    const unsigned char* __restrict__ w_q,
    const __half* __restrict__ scales,
    const __half* __restrict__ zeros,
    __half* __restrict__ y,
    int M, int N, int K, int n_groups
) {
    int n = blockIdx.x * blockDim.x + threadIdx.x;
    int m = blockIdx.y;

    if (n >= N || m >= M) return;

    float acc = 0.0f;

    for (int g = 0; g < n_groups; ++g) {
        int k_base = g * 128;
        __half sc = scales[g * N + n];
        __half ze = zeros[g * N + n];
        float scale = __half2float(sc);
        float zero = __half2float(ze);

        for (int kk = 0; kk < 128; kk += 2) {
            int k_even = k_base + kk;
            int k_odd = k_base + kk + 1;
            int w_row = k_even >> 1;

            unsigned char w_p = w_q[w_row * N + n];
            unsigned char w_e = w_p & 0xF;
            unsigned char w_o = (w_p >> 4) & 0xF;

            float w_deq_e = ((float)w_e - zero) * scale;
            float w_deq_o = ((float)w_o - zero) * scale;

            float x_e = __half2float(x[m * K + k_even]);
            float x_o = __half2float(x[m * K + k_odd]);

            acc += x_e * w_deq_e;
            acc += x_o * w_deq_o;
        }
    }

    y[m * N + n] = __float2half(acc);
}
"""
tool
stdout (26 chars)
Edit applied successfully.
assistant
in 987out 958cache_r 72416cache_w 0
assistant
bash
args
{
  "command": "cd /home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm && python check.py 2>&1",
  "description": "Run check.py correctness tests",
  "timeout": 180000
}
tool
stdout (95 chars)
FAIL: import error: dynamic module does not define module export function (PyInit_w4a16_fused)
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in 1018out 56cache_r 73376cache_w 0
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edit /home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
diff (8 lines)
--- a//home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
+++ b//home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
@@ -157,4 +157,5 @@
     cpp_sources="",
     cuda_sources=cuda_source,
     extra_cuda_cflags=["--use_fast_math", "-O3"],
+    is_python_module=False,
 )
args
{
  "filePath": "/home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py",
  "newString": "<207 chars \u2014 see below>",
  "oldString": "<179 chars \u2014 see below>"
}
newString (207 chars)
w4a16_kernel = torch.utils.cpp_extension.load_inline(
    name="w4a16_fused",
    cpp_sources="",
    cuda_sources=cuda_source,
    extra_cuda_cflags=["--use_fast_math", "-O3"],
    is_python_module=False,
)
oldString (179 chars)
w4a16_kernel = torch.utils.cpp_extension.load_inline(
    name="w4a16_fused",
    cpp_sources="",
    cuda_sources=cuda_source,
    extra_cuda_cflags=["--use_fast_math", "-O3"],
)
tool
stdout (26 chars)
Edit applied successfully.
assistant
in 141out 159cache_r 74368cache_w 0
assistant
bash
args
{
  "command": "<172 chars \u2014 see below>",
  "description": "Check load_inline params"
}
command (172 chars)
python -c "
import torch.utils.cpp_extension as ext
import inspect
sig = inspect.signature(ext.load_inline)
for p in sig.parameters.values():
    print(p.name, p.default)
"
tool
stdout (410 chars)
name <class 'inspect._empty'>
cpp_sources <class 'inspect._empty'>
cuda_sources None
sycl_sources None
functions None
extra_cflags None
extra_cuda_cflags None
extra_sycl_cflags None
extra_ldflags None
extra_include_paths None
build_directory None
verbose False
with_cuda None
with_sycl None
is_python_module True
with_pytorch_error_handling True
keep_intermediates True
use_pch False
no_implicit_headers False
assistant
in 208out 71cache_r 74496cache_w 0
assistant
bash
args
{
  "command": "<1801 chars \u2014 see below>",
  "description": "Test load_inline API",
  "timeout": 60000
}
command (1801 chars)
python -c "
import torch
# Try using torch._utils to get the compiled function
src = '''
#include <cuda_bf16.h>

extern \"C\"
__global__
void w4a16_kernel(
    const __nv_bfloat16* __restrict__ x,
    const unsigned char* __restrict__ w_q,
    const __nv_bfloat16* __restrict__ scales,
    const __nv_bfloat16* __restrict__ zeros,
    __nv_bfloat16* __restrict__ y,
    int M, int N, int K, int n_groups
) {
    int n = blockIdx.x * blockDim.x + threadIdx.x;
    int m = blockIdx.y;
    if (n >= N || m >= M) return;
    float acc = 0.0f;
    for (int g = 0; g < n_groups; ++g) {
        int k_base = g * 128;
        __nv_bfloat16 sc = scales[g * N + n];
        __nv_bfloat16 ze = zeros[g * N + n];
        float scale = __bfloat162float(sc);
        float zero = __bfloat162float(ze);
        for (int kk = 0; kk < 128; kk += 2) {
            int k_even = k_base + kk;
            int k_odd = k_base + kk + 1;
            int w_row = k_even >> 1;
            unsigned char w_p = w_q[w_row * N + n];
            unsigned char w_e = w_p & 0xF;
            unsigned char w_o = (w_p >> 4) & 0xF;
            float w_deq_e = ((float)w_e - zero) * scale;
            float w_deq_o = ((float)w_o - zero) * scale;
            float x_e = __bfloat162float(x[m * K + k_even]);
            float x_o = __bfloat162float(x[m * K + k_odd]);
            acc += x_e * w_deq_e;
            acc += x_o * w_deq_o;
        }
    }
    y[m * N + n] = __float2bfloat16(acc);
}
'''
try:
    m = torch.utils.cpp_extension.load_inline(
        name='test_w4a16',
        cpp_sources='',
        cuda_sources=src,
        extra_cuda_cflags=['--use_fast_math', '-O3'],
        functions=['w4a16_kernel'],
        is_python_module=False,
    )
    print('Success:', dir(m))
except Exception as e:
    print('Error:', e)
" 2>&1
tool
stdout (61 chars)
Error: module 'torch.utils' has no attribute 'cpp_extension'
assistant
in 210out 545cache_r 74688cache_w 0
assistant
bash
args
{
  "command": "python check.py 2>&1",
  "description": "Run check.py",
  "timeout": 180000
}
tool
stdout (879 chars)
Traceback (most recent call last):
  File "/home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/check.py", line 112, in <module>
    main()
  File "/home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/check.py", line 73, in main
    sol_out = sol_model(*inputs)
              ^^^^^^^^^^^^^^^^^^
  File "/home/infatoshi/.local/lib/python3.12/site-packages/torch/nn/modules/module.py", line 1779, in _wrapped_call_impl
    return self._call_impl(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/infatoshi/.local/lib/python3.12/site-packages/torch/nn/modules/module.py", line 1790, in _call_impl
    return forward_call(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py", line 129, in forward
    w4a16_kernel(
TypeError: 'str' object is not callable
assistant
in 664out 46cache_r 74880cache_w 0
assistant
bash
args
{
  "command": "<1663 chars \u2014 see below>",
  "description": "Test load_inline",
  "timeout": 60000
}
command (1663 chars)
python -c "
import torch
src = '''
#include <cuda_bf16.h>

extern \"C\"
__global__
void w4a16_kernel(
    const __nv_bfloat16* __restrict__ x,
    const unsigned char* __restrict__ w_q,
    const __nv_bfloat16* __restrict__ scales,
    const __nv_bfloat16* __restrict__ zeros,
    __nv_bfloat16* __restrict__ y,
    int M, int N, int K, int n_groups
) {
    int n = blockIdx.x * blockDim.x + threadIdx.x;
    int m = blockIdx.y;
    if (n >= N || m >= M) return;
    float acc = 0.0f;
    for (int g = 0; g < n_groups; ++g) {
        int k_base = g * 128;
        __nv_bfloat16 sc = scales[g * N + n];
        __nv_bfloat16 ze = zeros[g * N + n];
        float scale = __bfloat162float(sc);
        float zero = __bfloat162float(ze);
        for (int kk = 0; kk < 128; kk += 2) {
            int k_even = k_base + kk;
            int k_odd = k_base + kk + 1;
            int w_row = k_even >> 1;
            unsigned char w_p = w_q[w_row * N + n];
            unsigned char w_e = w_p & 0xF;
            unsigned char w_o = (w_p >> 4) & 0xF;
            float w_deq_e = ((float)w_e - zero) * scale;
            float w_deq_o = ((float)w_o - zero) * scale;
            float x_e = __bfloat162float(x[m * K + k_even]);
            float x_o = __bfloat162float(x[m * K + k_odd]);
            acc += x_e * w_deq_e;
            acc += x_o * w_deq_o;
        }
    }
    y[m * N + n] = __float2bfloat16(acc);
}
'''
m = torch.utils.cpp_extension.load_inline(
    name='test_w4a16',
    cpp_sources='',
    cuda_sources=src,
    extra_cuda_cflags=['--use_fast_math', '-O3'],
    functions=['w4a16_kernel'],
    is_python_module=False,
)
print(type(m))
print(dir(m))
" 2>&1
tool
stdout (145 chars)
Traceback (most recent call last):
  File "<string>", line 44, in <module>
AttributeError: module 'torch.utils' has no attribute 'cpp_extension'
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in 338out 591cache_r 75520cache_w 0
assistant
bash
args
{
  "command": "python -c \"import torch; print(dir(torch)); print('---'); from torch.utils.cpp_extension import load_inline; print('found')\" 2>&1",
  "description": "Find correct load_inline path"
}
tool
stdout (25032 chars) — TRUNCATED
['AVG', 'AcceleratorError', 'AggregationType', 'AliasDb', 'AnyType', 'Argument', 'ArgumentSpec', 'AwaitType', 'BFloat16Storage', 'BFloat16Tensor', 'BenchmarkConfig', 'BenchmarkExecutionStats', 'Block', 'BoolStorage', 'BoolTensor', 'BoolType', 'BufferDict', 'ByteStorage', 'ByteTensor', 'CallStack', 'Capsule', 'CharStorage', 'CharTensor', 'ClassType', 'Code', 'CompilationUnit', 'CompleteArgumentSpec', 'ComplexDoubleStorage', 'ComplexFloatStorage', 'ComplexType', 'ConcreteModuleType', 'ConcreteModuleTypeBuilder', 'DeepCopyMemoTable', 'DeserializationStorageContext', 'DeviceObjType', 'DictType', 'DisableTorchFunction', 'DisableTorchFunctionSubclass', 'DispatchKey', 'DispatchKeySet', 'DoubleStorage', 'DoubleTensor', 'EnumType', 'ErrorReport', 'Event', 'ExcludeDispatchKeyGuard', 'ExecutionPlan', 'FatalError', 'FileCheck', 'FloatStorage', 'FloatTensor', 'FloatType', 'FunctionSchema', 'Future', 'FutureType', 'Generator', 'GradScaler', 'Gradient', 'Graph', 'GraphExecutorState', 'HalfStorage', 'HalfTensor', 'IODescriptor', 'InferredType', 'IntStorage', 'IntTensor', 'IntType', 'InterfaceType', 'JITException', 'ListType', 'LiteScriptModule', 'LockingLogger', 'LoggerBase', 'LongStorage', 'LongTensor', 'ModuleDict', 'Node', 'NoneType', 'NoopLogger', 'NumberType', 'OperatorInfo', 'OptionalType', 'OutOfMemoryError', 'PRIVATE_OPS', 'ParameterDict', 'PyObjectType', 'PyTorchFileReader', 'PyTorchFileWriter', 'QInt32Storage', 'QInt8Storage', 'QUInt2x4Storage', 'QUInt4x2Storage', 'QUInt8Storage', 

... (23532 more chars)
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in 657out 70cache_r 75840cache_w 0
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bash
args
{
  "command": "<379 chars \u2014 see below>",
  "description": "Test load_inline return value",
  "timeout": 60000
}
command (379 chars)
python -c "
import torch.utils.cpp_extension as ext
src = '''
#include <cuda_bf16.h>
extern \"C\" __global__ void w4a16_kernel(float* x) { }
'''
m = ext.load_inline(
    name='test_mod',
    cpp_sources='',
    cuda_sources=src,
    extra_cuda_cflags=['-O3'],
    functions=['w4a16_kernel'],
    is_python_module=False,
)
print(type(m))
print(dir(m))
print(m.w4a16_kernel)
" 2>&1
tool
stdout (3295 chars) — TRUNCATED
Traceback (most recent call last):
  File "/home/infatoshi/.local/lib/python3.12/site-packages/torch/utils/cpp_extension.py", line 2774, in _run_ninja_build
    subprocess.run(
  File "/usr/lib/python3.12/subprocess.py", line 571, in run
    raise CalledProcessError(retcode, process.args,
subprocess.CalledProcessError: Command '['ninja', '-v']' returned non-zero exit status 1.

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "<string>", line 7, in <module>
  File "/home/infatoshi/.local/lib/python3.12/site-packages/torch/utils/cpp_extension.py", line 2174, in load_inline
    return _jit_compile(
           ^^^^^^^^^^^^^
  File "/home/infatoshi/.local/lib/python3.12/site-packages/torch/utils/cpp_extension.py", line 2268, in _jit_compile
    _write_ninja_file_and_build_library(
  File "/home/infatoshi/.local/lib/python3.12/site-packages/torch/utils/cpp_extension.py", line 2429, in _write_ninja_file_and_build_library
    _run_ninja_build(
  File "/home/infatoshi/.local/lib/python3.12/site-packages/torch/utils/cpp_extension.py", line 2791, in _run_ninja_build
    raise RuntimeError(message) from e
RuntimeError: Error building extension 'test_mod': [1/3] c++ -MMD -MF main.o.d -DTORCH_EXTENSION_NAME=test_mod -DTORCH_API_INCLUDE_EXTENSION_H -isystem /home/infatoshi/.local/lib/python3.12/site-packages/torch/include -isystem /home/infatoshi/.local/lib/python3.12/site-packages/torch/include/torch/csrc/api/include -isystem 

... (1795 more chars)
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in 7805out 144cache_r 76480cache_w 0
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write /home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
diff (31 lines)
--- a//home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
+++ b//home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
@@ -34,7 +34,6 @@
 
 
 cuda_source = r"""
-#include <cuda_fp16.h>
 #include <cuda_bf16.h>
 
 extern "C"
@@ -126,7 +125,7 @@
         grid_x = (N + BLOCK_N - 1) // BLOCK_N
         grid_y = M
 
-        w4a16_kernel(
+        w4a16_fused.w4a16_kernel(
             torch.cuda.current_stream(),
             [grid_x, grid_y, 1],
             [BLOCK_N, 1, 1],
@@ -152,10 +151,9 @@
     return [M, N, K]
 
 
-w4a16_kernel = torch.utils.cpp_extension.load_inline(
+w4a16_fused = torch.utils.cpp_extension.load_inline(
     name="w4a16_fused",
     cpp_sources="",
     cuda_sources=cuda_source,
     extra_cuda_cflags=["--use_fast_math", "-O3"],
-    is_python_module=False,
 )
args
{
  "content": "<4397 chars \u2014 see diff>",
  "filePath": "/home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py"
}
tool
stdout (24 chars)
Wrote file successfully.
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in 1156out 1493cache_r 84256cache_w 0
assistant
bash
args
{
  "command": "<415 chars \u2014 see below>",
  "description": "Test load_inline is_python_module False",
  "timeout": 60000
}
command (415 chars)
python -c "
import torch.utils.cpp_extension as ext
src = '''
#include <cuda_bf16.h>
extern \"C\" __global__ void w4a16_kernel(float* x) { }
'''
try:
    m = ext.load_inline(
        name='test_mod2',
        cpp_sources='',
        cuda_sources=src,
        extra_cuda_cflags=['-O3'],
        is_python_module=False,
    )
    print('Success:', type(m), dir(m))
except Exception as e:
    print('Error:', e)
" 2>&1
tool
stdout (1004 chars)
Success: <class 'str'> ['__add__', '__class__', '__contains__', '__delattr__', '__dir__', '__doc__', '__eq__', '__format__', '__ge__', '__getattribute__', '__getitem__', '__getnewargs__', '__getstate__', '__gt__', '__hash__', '__init__', '__init_subclass__', '__iter__', '__le__', '__len__', '__lt__', '__mod__', '__mul__', '__ne__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__rmod__', '__rmul__', '__setattr__', '__sizeof__', '__str__', '__subclasshook__', 'capitalize', 'casefold', 'center', 'count', 'encode', 'endswith', 'expandtabs', 'find', 'format', 'format_map', 'index', 'isalnum', 'isalpha', 'isascii', 'isdecimal', 'isdigit', 'isidentifier', 'islower', 'isnumeric', 'isprintable', 'isspace', 'istitle', 'isupper', 'join', 'ljust', 'lower', 'lstrip', 'maketrans', 'partition', 'removeprefix', 'removesuffix', 'replace', 'rfind', 'rindex', 'rjust', 'rpartition', 'rsplit', 'rstrip', 'split', 'splitlines', 'startswith', 'strip', 'swapcase', 'title', 'translate', 'upper', 'zfill']
assistant
in 1530out 116cache_r 85408cache_w 0
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write /home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
diff (8 lines)
--- a//home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
+++ b//home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
@@ -156,4 +156,5 @@
     cpp_sources="",
     cuda_sources=cuda_source,
     extra_cuda_cflags=["--use_fast_math", "-O3"],
+    is_python_module=False,
 )
args
{
  "content": "<4425 chars \u2014 see diff>",
  "filePath": "/home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py"
}
tool
stdout (24 chars)
Wrote file successfully.
assistant
in 541out 1477cache_r 86912cache_w 0
assistant
write /home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
diff (23 lines)
--- a//home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
+++ b//home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
@@ -125,7 +125,7 @@
         grid_x = (N + BLOCK_N - 1) // BLOCK_N
         grid_y = M
 
-        w4a16_fused.w4a16_kernel(
+        _w4a16_kernel(
             torch.cuda.current_stream(),
             [grid_x, grid_y, 1],
             [BLOCK_N, 1, 1],
@@ -151,10 +151,9 @@
     return [M, N, K]
 
 
-w4a16_fused = torch.utils.cpp_extension.load_inline(
+_w4a16_kernel = torch.utils.cpp_extension.load_inline(
     name="w4a16_fused",
     cpp_sources="",
     cuda_sources=cuda_source,
     extra_cuda_cflags=["--use_fast_math", "-O3"],
-    is_python_module=False,
 )
args
{
  "content": "<4388 chars \u2014 see diff>",
  "filePath": "/home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py"
}
tool
stdout (24 chars)
Wrote file successfully.
assistant
in 1561out 1457cache_r 87424cache_w 0
assistant
write /home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
diff (54 lines)
--- a//home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
+++ b//home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
@@ -84,6 +84,23 @@
 }
 """
 
+cpp_source = r"""
+#include <torch/extension.h>
+#include <pybind11/pybind11.h>
+
+void w4a16_kernel(
+    const torch::Tensor& x,
+    const torch::Tensor& w_q,
+    const torch::Tensor& scales,
+    const torch::Tensor& zeros,
+    torch::Tensor& y,
+    int M, int N, int K, int n_groups);
+
+PYBIND11_MODULE(w4a16_lib, m) {
+    m.def("w4a16_kernel", &w4a16_kernel);
+}
+"""
+
 
 class Model(nn.Module):
     def __init__(self, M: int, N: int, K: int, group_size: int = GROUP_SIZE):
@@ -125,11 +142,7 @@
         grid_x = (N + BLOCK_N - 1) // BLOCK_N
         grid_y = M
 
-        _w4a16_kernel(
-            torch.cuda.current_stream(),
-            [grid_x, grid_y, 1],
-            [BLOCK_N, 1, 1],
-            0,
+        w4a16_lib.w4a16_kernel(
             x, self.w_q, self.scales, self.zeros, y,
             M, N, K, n_groups
         )
@@ -151,9 +164,11 @@
     return [M, N, K]
 
 
-_w4a16_kernel = torch.utils.cpp_extension.load_inline(
-    name="w4a16_fused",
-    cpp_sources="",
+w4a16_lib = torch.utils.cpp_extension.load_inline(
+    name="w4a16_lib",
+    cpp_sources=cpp_source,
     cuda_sources=cuda_source,
     extra_cuda_cflags=["--use_fast_math", "-O3"],
+    extra_include_paths=[],
+    functions=["w4a16_kernel"],
 )
args
{
  "content": "<4706 chars \u2014 see diff>",
  "filePath": "/home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py"
}
tool
stdout (24 chars)
Wrote file successfully.
assistant
in 1545out 1592cache_r 88960cache_w 0
assistant
bash
args
{
  "command": "<1914 chars \u2014 see below>",
  "description": "Test pybind approach",
  "timeout": 60000
}
command (1914 chars)
python -c "
import torch
src = '''
#include <cuda_bf16.h>
#include <torch/extension.h>
#include <pybind11/pybind11.h>

void w4a16_kernel(
    const torch::Tensor& x,
    const torch::Tensor& w_q,
    const torch::Tensor& scales,
    const torch::Tensor& zeros,
    torch::Tensor& y,
    int M, int N, int K, int n_groups);

void w4a16_kernel(
    const torch::Tensor& x,
    const torch::Tensor& w_q,
    const torch::Tensor& scales,
    const torch::Tensor& zeros,
    torch::Tensor& y,
    int M, int N, int K, int n_groups) {
    int n = blockIdx.x * blockDim.x + threadIdx.x;
    int m = blockIdx.y;
    if (n >= N || m >= M) return;
    float acc = 0.0f;
    for (int g = 0; g < n_groups; ++g) {
        int k_base = g * 128;
        __nv_bfloat16 sc = scales[g * N + n];
        __nv_bfloat16 ze = zeros[g * N + n];
        float scale = __bfloat162float(sc);
        float zero = __bfloat162float(ze);
        for (int kk = 0; kk < 128; kk += 2) {
            int k_even = k_base + kk;
            int k_odd = k_base + kk + 1;
            int w_row = k_even >> 1;
            unsigned char w_p = w_q[w_row * N + n];
            unsigned char w_e = w_p & 0xF;
            unsigned char w_o = (w_p >> 4) & 0xF;
            float w_deq_e = ((float)w_e - zero) * scale;
            float w_deq_o = ((float)w_o - zero) * scale;
            float x_e = __bfloat162float(x[m * K + k_even]);
            float x_o = __bfloat162float(x[m * K + k_odd]);
            acc += x_e * w_deq_e;
            acc += x_o * w_deq_o;
        }
    }
    y[m * N + n] = __float2bfloat16(acc);
}

PYBIND11_MODULE(w4a16_test, m) {
    m.def(\"w4a16_kernel\", &w4a16_kernel);
}
'''
import torch.utils.cpp_extension as ext
m = ext.load_inline(
    name='w4a16_test',
    cpp_sources=src,
    cuda_sources='',
    extra_cuda_cflags=['--use_fast_math', '-O3'],
    functions=['w4a16_kernel'],
)
print('Success:', type(m), dir(m))
" 2>&1
tool
stdout (2303 chars) — TRUNCATED
Traceback (most recent call last):
  File "/home/infatoshi/.local/lib/python3.12/site-packages/torch/utils/cpp_extension.py", line 2774, in _run_ninja_build
    subprocess.run(
  File "/usr/lib/python3.12/subprocess.py", line 571, in run
    raise CalledProcessError(retcode, process.args,
subprocess.CalledProcessError: Command '['ninja', '-v']' returned non-zero exit status 1.

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "<string>", line 56, in <module>
  File "/home/infatoshi/.local/lib/python3.12/site-packages/torch/utils/cpp_extension.py", line 2174, in load_inline
    return _jit_compile(
           ^^^^^^^^^^^^^
  File "/home/infatoshi/.local/lib/python3.12/site-packages/torch/utils/cpp_extension.py", line 2268, in _jit_compile
    _write_ninja_file_and_build_library(
  File "/home/infatoshi/.local/lib/python3.12/site-packages/torch/utils/cpp_extension.py", line 2429, in _write_ninja_file_and_build_library
    _run_ninja_build(
  File "/home/infatoshi/.local/lib/python3.12/site-packages/torch/utils/cpp_extension.py", line 2791, in _run_ninja_build
    raise RuntimeError(message) from e
RuntimeError: Error building extension 'w4a16_test': [1/2] c++ -MMD -MF main.o.d -DTORCH_EXTENSION_NAME=w4a16_test -DTORCH_API_INCLUDE_EXTENSION_H -isystem /home/infatoshi/.local/lib/python3.12/site-packages/torch/include -isystem /home/infatoshi/.local/lib/python3.12/site-packages/torch/include/torch/csrc/api/include -isy

... (803 more chars)
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assistant
Let me try a different approach using `torch.cuda.jit.inline_kernel`:
assistant
bash
args
{
  "command": "<69 chars \u2014 see below>",
  "description": "Check torch.cuda.jit module"
}
command (69 chars)
python -c "
import torch
print(dir(torch.cuda.jit))
" 2>&1 | head -30
tool
stdout (133 chars)
Traceback (most recent call last):
  File "<string>", line 3, in <module>
AttributeError: module 'torch.cuda' has no attribute 'jit'
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in 1373out 23cache_r 92096cache_w 0
assistant
bash
args
{
  "command": "<2465 chars \u2014 see below>",
  "description": "Test simpler load_inline",
  "timeout": 60000
}
command (2465 chars)
python -c "
import torch.utils.cpp_extension as ext
src = '''
#include <torch/extension.h>
#include <cuda_bf16.h>

__global__ void w4a16_kernel(
    const __nv_bfloat16* __restrict__ x,
    const unsigned char* __restrict__ w_q,
    const __nv_bfloat16* __restrict__ scales,
    const __nv_bfloat16* __restrict__ zeros,
    __nv_bfloat16* __restrict__ y,
    int M, int N, int K, int n_groups
) {
    int n = blockIdx.x * blockDim.x + threadIdx.x;
    int m = blockIdx.y;
    if (n >= N || m >= M) return;
    float acc = 0.0f;
    for (int g = 0; g < n_groups; ++g) {
        int k_base = g * 128;
        __nv_bfloat16 sc = scales[g * N + n];
        __nv_bfloat16 ze = zeros[g * N + n];
        float scale = __bfloat162float(sc);
        float zero = __bfloat162float(ze);
        for (int kk = 0; kk < 128; kk += 2) {
            int k_even = k_base + kk;
            int k_odd = k_base + kk + 1;
            int w_row = k_even >> 1;
            unsigned char w_p = w_q[w_row * N + n];
            unsigned char w_e = w_p & 0xF;
            unsigned char w_o = (w_p >> 4) & 0xF;
            float w_deq_e = ((float)w_e - zero) * scale;
            float w_deq_o = ((float)w_o - zero) * scale;
            float x_e = __bfloat162float(x[m * K + k_even]);
            float x_o = __bfloat162float(x[m * K + k_odd]);
            acc += x_e * w_deq_e;
            acc += x_o * w_deq_o;
        }
    }
    y[m * N + n] = __float2bfloat16(acc);
}

torch::Tensor w4a16_kernel_py(
    const torch::Tensor& x,
    const torch::Tensor& w_q,
    const torch::Tensor& scales,
    const torch::Tensor& zeros,
    int M, int N, int K, int n_groups
) {
    torch::Tensor y = torch::empty({M, N}, x.options());
    auto stream = c10::cuda::getCurrentCUDAStream();
    int BLOCK_N = 128;
    dim3 grid((N + BLOCK_N - 1) / BLOCK_N, M, 1);
    dim3 block(BLOCK_N, 1, 1);
    w4a16_kernel<<<grid, block, 0, stream>>>(
        x.data_ptr<torch::Half>(), w_q.data_ptr<unsigned char>(),
        scales.data_ptr<torch::Half>(), zeros.data_ptr<torch::Half>(),
        y.data_ptr<torch::Half>(), M, N, K, n_groups);
    return y;
}

TORCH_LIBRARY(w4a16_test, m) {
    m.def(\"w4a16_kernel(Tensor x, Tensor w_q, Tensor scales, Tensor zeros, int M, int N, int K, int n_groups) -> Tensor\");
}
"""
m = ext.load_inline(
    name='w4a16_test',
    cpp_sources='',
    cuda_sources=src,
    extra_cuda_cflags=['--use_fast_math', '-O3'],
    is_python_module=False,
)
print(type(m), m)
" 2>&1
tool
stdout (20 chars)
zsh:74: unmatched "
assistant
in 139out 780cache_r 93440cache_w 0
assistant
write /home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
diff (87 lines)
--- a//home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
+++ b//home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
@@ -34,9 +34,9 @@
 
 
 cuda_source = r"""
+#include <torch/extension.h>
 #include <cuda_bf16.h>
 
-extern "C"
 __global__
 void w4a16_kernel(
     const __nv_bfloat16* __restrict__ x,
@@ -82,22 +82,31 @@
 
     y[m * N + n] = __float2bfloat16(acc);
 }
-"""
 
-cpp_source = r"""
-#include <torch/extension.h>
-#include <pybind11/pybind11.h>
-
-void w4a16_kernel(
+torch::Tensor w4a16_kernel_py(
     const torch::Tensor& x,
     const torch::Tensor& w_q,
     const torch::Tensor& scales,
     const torch::Tensor& zeros,
-    torch::Tensor& y,
-    int M, int N, int K, int n_groups);
+    int M, int N, int K, int n_groups
+) {
+    torch::Tensor y = torch::empty({M, N}, x.options());
+    auto stream = c10::cuda::getCurrentCUDAStream();
+    int BLOCK_N = 128;
+    dim3 grid((N + BLOCK_N - 1) / BLOCK_N, M, 1);
+    dim3 block(BLOCK_N, 1, 1);
+    w4a16_kernel<<<grid, block, 0, stream>>>(
+        reinterpret_cast<const __nv_bfloat16*>(x.data_ptr()),
+        w_q.data_ptr<unsigned char>(),
+        reinterpret_cast<const __nv_bfloat16*>(scales.data_ptr()),
+        reinterpret_cast<const __nv_bfloat16*>(zeros.data_ptr()),
+        reinterpret_cast<__nv_bfloat16*>(y.data_ptr()),
+        M, N, K, n_groups);
+    return y;
+}
 
-PYBIND11_MODULE(w4a16_lib, m) {
-    m.def("w4a16_kernel", &w4a16_kernel);
+TORCH_LIBRARY(w4a16_cuda, m) {
+    m.def("w4a16_kernel(Tensor x, Tensor w_q, Tensor scales, Tensor zeros, int M, int N, int K, int n_groups) -> Tensor");
 }
 """
 
@@ -136,14 +145,8 @@
         K = self.K
         n_groups = K // self.group_size
 
-        y = torch.empty((M, N), dtype=torch.bfloat16, device=x.device)
-
-        BLOCK_N = 128
-        grid_x = (N + BLOCK_N - 1) // BLOCK_N
-        grid_y = M
-
-        w4a16_lib.w4a16_kernel(
-            x, self.w_q, self.scales, self.zeros, y,
+        y = w4a16_cuda.w4a16_kernel(
+            x, self.w_q, self.scales, self.zeros,
             M, N, K, n_groups
         )
 
@@ -164,11 +167,9 @@
     return [M, N, K]
 
 
-w4a16_lib = torch.utils.cpp_extension.load_inline(
-    name="w4a16_lib",
-    cpp_sources=cpp_source,
+w4a16_cuda = torch.utils.cpp_extension.load_inline(
+    name="w4a16_cuda",
+    cpp_sources="",
     cuda_sources=cuda_source,
     extra_cuda_cflags=["--use_fast_math", "-O3"],
-    extra_include_paths=[],
-    functions=["w4a16_kernel"],
 )
args
{
  "content": "<5083 chars \u2014 see diff>",
  "filePath": "/home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py"
}
tool
stdout (24 chars)
Wrote file successfully.
assistant
in 877out 1712cache_r 93568cache_w 0
assistant
bash
args
{
  "command": "python check.py 2>&1",
  "description": "Run check.py",
  "timeout": 180000
}
tool
stdout (2385 chars) — TRUNCATED
FAIL: import error: Error building extension 'w4a16_cuda': [1/3] /usr/local/cuda-13/bin/nvcc -MD -MF cuda.cuda.o.d -DTORCH_EXTENSION_NAME=w4a16_cuda -DTORCH_API_INCLUDE_EXTENSION_H -isystem /home/infatoshi/.local/lib/python3.12/site-packages/torch/include -isystem /home/infatoshi/.local/lib/python3.12/site-packages/torch/include/torch/csrc/api/include -isystem /usr/local/cuda-13/include -isystem /usr/include/python3.12 -D__CUDA_NO_HALF_OPERATORS__ -D__CUDA_NO_HALF_CONVERSIONS__ -D__CUDA_NO_BFLOAT16_CONVERSIONS__ -D__CUDA_NO_HALF2_OPERATORS__ --expt-relaxed-constexpr -gencode=arch=compute_120,code=compute_120 -gencode=arch=compute_120,code=sm_120 --compiler-options '-fPIC' --use_fast_math -O3 -std=c++17 -c /home/infatoshi/.cache/torch_extensions/py312_cu130/w4a16_cuda/cuda.cu -o cuda.cuda.o 
FAILED: cuda.cuda.o 
/usr/local/cuda-13/bin/nvcc -MD -MF cuda.cuda.o.d -DTORCH_EXTENSION_NAME=w4a16_cuda -DTORCH_API_INCLUDE_EXTENSION_H -isystem /home/infatoshi/.local/lib/python3.12/site-packages/torch/include -isystem /home/infatoshi/.local/lib/python3.12/site-packages/torch/include/torch/csrc/api/include -isystem /usr/local/cuda-13/include -isystem /usr/include/python3.12 -D__CUDA_NO_HALF_OPERATORS__ -D__CUDA_NO_HALF_CONVERSIONS__ -D__CUDA_NO_BFLOAT16_CONVERSIONS__ -D__CUDA_NO_HALF2_OPERATORS__ --expt-relaxed-constexpr -gencode=arch=compute_120,code=compute_120 -gencode=arch=compute_120,code=sm_120 --compiler-options '-fPIC' --use_fast_math -O3 -std=c++17 -c /home/infatoshi/.cache/torc

... (885 more chars)
assistant
in 1746out 53cache_r 94432cache_w 0
assistant
bash
args
{
  "command": "<71 chars \u2014 see below>",
  "description": "Check torch.cuda.Stream API"
}
command (71 chars)
python -c "
import torch
ts = torch.cuda.Stream()
print(dir(ts))
" 2>&1
tool
stdout (593 chars)
['__class__', '__cuda_stream__', '__delattr__', '__dict__', '__dir__', '__doc__', '__enter__', '__eq__', '__exit__', '__format__', '__ge__', '__getattribute__', '__getstate__', '__gt__', '__hash__', '__init__', '__init_subclass__', '__le__', '__lt__', '__module__', '__ne__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__sizeof__', '__str__', '__subclasshook__', '_as_parameter_', 'cuda_stream', 'device', 'device_index', 'device_type', 'native_handle', 'priority', 'priority_range', 'query', 'record_event', 'stream_id', 'synchronize', 'wait_event', 'wait_stream']
assistant
in 850out 62cache_r 96160cache_w 0
assistant
write /home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
diff (75 lines)
--- a//home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
+++ b//home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
@@ -82,6 +82,11 @@
 
     y[m * N + n] = __float2bfloat16(acc);
 }
+"""
+
+cpp_source = r"""
+#include <torch/extension.h>
+#include <cuda_bf16.h>
 
 torch::Tensor w4a16_kernel_py(
     const torch::Tensor& x,
@@ -91,22 +96,28 @@
     int M, int N, int K, int n_groups
 ) {
     torch::Tensor y = torch::empty({M, N}, x.options());
-    auto stream = c10::cuda::getCurrentCUDAStream();
+    auto x_bf16 = reinterpret_cast<const __nv_bfloat16*>(x.data_ptr());
+    auto w_q_ptr = w_q.data_ptr<unsigned char>();
+    auto scales_bf16 = reinterpret_cast<const __nv_bfloat16*>(scales.data_ptr());
+    auto zeros_bf16 = reinterpret_cast<const __nv_bfloat16*>(zeros.data_ptr());
+    auto y_bf16 = reinterpret_cast<__nv_bfloat16*>(y.data_ptr());
+
     int BLOCK_N = 128;
     dim3 grid((N + BLOCK_N - 1) / BLOCK_N, M, 1);
     dim3 block(BLOCK_N, 1, 1);
-    w4a16_kernel<<<grid, block, 0, stream>>>(
-        reinterpret_cast<const __nv_bfloat16*>(x.data_ptr()),
-        w_q.data_ptr<unsigned char>(),
-        reinterpret_cast<const __nv_bfloat16*>(scales.data_ptr()),
-        reinterpret_cast<const __nv_bfloat16*>(zeros.data_ptr()),
-        reinterpret_cast<__nv_bfloat16*>(y.data_ptr()),
-        M, N, K, n_groups);
+    w4a16_kernel<<<grid, block>>>(
+        x_bf16, w_q_ptr, scales_bf16, zeros_bf16, y_bf16, M, N, K, n_groups);
     return y;
 }
 
-TORCH_LIBRARY(w4a16_cuda, m) {
-    m.def("w4a16_kernel(Tensor x, Tensor w_q, Tensor scales, Tensor zeros, int M, int N, int K, int n_groups) -> Tensor");
+torch::Tensor w4a16_kernel_wrapper(
+    const torch::Tensor& x,
+    const torch::Tensor& w_q,
+    const torch::Tensor& scales,
+    const torch::Tensor& zeros,
+    int M, int N, int K, int n_groups
+) {
+    return w4a16_kernel_py(x, w_q, scales, zeros, M, N, K, n_groups);
 }
 """
 
@@ -145,7 +156,7 @@
         K = self.K
         n_groups = K // self.group_size
 
-        y = w4a16_cuda.w4a16_kernel(
+        y = w4a16_lib.w4a16_kernel_wrapper(
             x, self.w_q, self.scales, self.zeros,
             M, N, K, n_groups
         )
@@ -167,9 +178,9 @@
     return [M, N, K]
 
 
-w4a16_cuda = torch.utils.cpp_extension.load_inline(
-    name="w4a16_cuda",
-    cpp_sources="",
+w4a16_lib = torch.utils.cpp_extension.load_inline(
+    name="w4a16_lib",
+    cpp_sources=cpp_source,
     cuda_sources=cuda_source,
     extra_cuda_cflags=["--use_fast_math", "-O3"],
 )
args
{
  "content": "<5335 chars \u2014 see diff>",
  "filePath": "/home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py"
}
tool
stdout (24 chars)
Wrote file successfully.
assistant
in 273out 1746cache_r 96992cache_w 0
assistant
bash
args
{
  "command": "python check.py 2>&1",
  "description": "Run check.py",
  "timeout": 180000
}
tool
stdout (2610 chars) — TRUNCATED
FAIL: import error: Error building extension 'w4a16_lib': [1/3] c++ -MMD -MF main.o.d -DTORCH_EXTENSION_NAME=w4a16_lib -DTORCH_API_INCLUDE_EXTENSION_H -isystem /home/infatoshi/.local/lib/python3.12/site-packages/torch/include -isystem /home/infatoshi/.local/lib/python3.12/site-packages/torch/include/torch/csrc/api/include -isystem /usr/local/cuda-13/include -isystem /usr/include/python3.12 -fPIC -std=c++17 -c /home/infatoshi/.cache/torch_extensions/py312_cu130/w4a16_lib/main.cpp -o main.o 
FAILED: main.o 
c++ -MMD -MF main.o.d -DTORCH_EXTENSION_NAME=w4a16_lib -DTORCH_API_INCLUDE_EXTENSION_H -isystem /home/infatoshi/.local/lib/python3.12/site-packages/torch/include -isystem /home/infatoshi/.local/lib/python3.12/site-packages/torch/include/torch/csrc/api/include -isystem /usr/local/cuda-13/include -isystem /usr/include/python3.12 -fPIC -std=c++17 -c /home/infatoshi/.cache/torch_extensions/py312_cu130/w4a16_lib/main.cpp -o main.o 
/home/infatoshi/.cache/torch_extensions/py312_cu130/w4a16_lib/main.cpp: In function ‘at::Tensor w4a16_kernel_py(const at::Tensor&, const at::Tensor&, const at::Tensor&, const at::Tensor&, int, int, int, int)’:
/home/infatoshi/.cache/torch_extensions/py312_cu130/w4a16_lib/main.cpp:23:5: error: ‘w4a16_kernel’ was not declared in this scope; did you mean ‘w4a16_kernel_py’?
   23 |     w4a16_kernel<<<grid, block>>>(
      |     ^~~~~~~~~~~~
      |     w4a16_kernel_py
/home/infatoshi/.cache/torch_extensions/py312_cu130/w4a16_lib/main.cpp:23:19: error: expe

... (1110 more chars)
assistant
in 1837out 52cache_r 97248cache_w 0
assistant
write /home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
diff (49 lines)
--- a//home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
+++ b//home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
@@ -82,11 +82,6 @@
 
     y[m * N + n] = __float2bfloat16(acc);
 }
-"""
-
-cpp_source = r"""
-#include <torch/extension.h>
-#include <cuda_bf16.h>
 
 torch::Tensor w4a16_kernel_py(
     const torch::Tensor& x,
@@ -108,16 +103,6 @@
     w4a16_kernel<<<grid, block>>>(
         x_bf16, w_q_ptr, scales_bf16, zeros_bf16, y_bf16, M, N, K, n_groups);
     return y;
-}
-
-torch::Tensor w4a16_kernel_wrapper(
-    const torch::Tensor& x,
-    const torch::Tensor& w_q,
-    const torch::Tensor& scales,
-    const torch::Tensor& zeros,
-    int M, int N, int K, int n_groups
-) {
-    return w4a16_kernel_py(x, w_q, scales, zeros, M, N, K, n_groups);
 }
 """
 
@@ -156,7 +141,7 @@
         K = self.K
         n_groups = K // self.group_size
 
-        y = w4a16_lib.w4a16_kernel_wrapper(
+        y = w4a16_lib.w4a16_kernel_py(
             x, self.w_q, self.scales, self.zeros,
             M, N, K, n_groups
         )
@@ -180,7 +165,7 @@
 
 w4a16_lib = torch.utils.cpp_extension.load_inline(
     name="w4a16_lib",
-    cpp_sources=cpp_source,
+    cpp_sources="",
     cuda_sources=cuda_source,
     extra_cuda_cflags=["--use_fast_math", "-O3"],
 )
args
{
  "content": "<4973 chars \u2014 see diff>",
  "filePath": "/home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py"
}
tool
stdout (24 chars)
Wrote file successfully.
assistant
in 895out 1675cache_r 99072cache_w 0
assistant
bash
args
{
  "command": "python check.py 2>&1",
  "description": "Run check.py",
  "timeout": 180000
}
tool
stdout (93 chars)
FAIL: import error: dynamic module does not define module export function (PyInit_w4a16_lib)
assistant
in 1742out 15cache_r 99936cache_w 0
assistant
write /home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
args
{
  "content": "<4973 chars \u2014 see below>",
  "filePath": "/home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py"
}
content (4973 chars — TRUNCATED)
"""Fused W4A16 GEMM — CUDA C++ via load_inline, AWQ/GPTQ-style asymmetric int4.

Dequantizes on-the-fly: (w_q[k,n] - zeros[g,n]) * scales[g,n] with group=128
along K. Two int4 weights are packed per uint8 byte (low nibble=even, high=odd).
"""
from __future__ import annotations

import torch
import torch.nn as nn
import torch.utils.cpp_extension

OP_TYPE = "gemm_w4a16"
SUPPORTED_PRECISIONS = ["int4_bf16"]
HARDWARE_REQUIRED = ["RTX_PRO_6000", "H100", "B200"]

GROUP_SIZE = 128


def _pack_int4(w_q: torch.Tensor) -> torch.Tensor:
    K, N = w_q.shape
    assert K % 2 == 0
    lo = w_q[0::2].to(torch.uint8) & 0xF
    hi = w_q[1::2].to(torch.uint8) & 0xF
    return (lo | (hi << 4)).contiguous()


def _unpack_int4(w_packed: torch.Tensor, K: int) -> torch.Tensor:
    Kh, N = w_packed.shape
    assert Kh * 2 == K
    out = torch.empty((K, N), dtype=torch.uint8, device=w_packed.device)
    out[0::2] = w_packed & 0xF
    out[1::2] = (w_packed >> 4) & 0xF
    return out


cuda_source = r"""
#include <torch/extension.h>
#include <cuda_bf16.h>

__global__
void w4a16_kernel(
    const __nv_bfloat16* __restrict__ x,
    const unsigned char* __restrict__ w_q,
    const __nv_bfloat16* __restrict__ scales,
    const __nv_bfloat16* __restrict__ zeros,
    __nv_bfloat16* __restrict__ y,
    int M, int N, int K, int n_groups
) {
    int n = blockIdx.x * blockDim.x + threadIdx.x;
    int m = blockIdx.y;

    if (n >= N || m >= M) return;

    float acc = 0.0f;

    for (int g = 0; g < n_groups; ++g) {
        int k_base = g * 128;
        __nv_bfloat16 sc = scales[g * N + n];
        __nv_bfloat16 ze = zeros[g * N + n];
        float scale = __bfloat162float(sc);
        float zero = __bfloat162float(ze);

        for (int kk = 0; kk < 128; kk += 2) {
            int k_even = k_base + kk;
            int k_odd = k_base + kk + 1;
            int w_row = k_even >> 1;

            unsigned char w_p = w_q[w_row * N + n];
            unsigned char w_e = w_p & 0xF;
            unsigned char w_o = (w_p >> 4) & 0xF;

            float w_deq_e = ((float)w_e - zero) * scale;
            float w_deq_o = ((float)w_o - zero) * scale;

            float x_e = __bfloat162float(x[m * K + k_even]);
            float x_o = __bfloat162float(x[m * K + k_odd]);

            acc += x_e * w_deq_e;
            acc += x_o * w_deq_o;
        }
    }

    y[m * N + n] = __float2bfloat16(acc);
}

torch::Tensor w4a16_kernel_py(
    const torch::Tensor& x,
    const torch::Tensor& w_q,
    const torch::Tensor& scales,
    const torch::Tensor& zeros,
    int M, int N, int K, int n_groups
) {
    torch::Tensor y = torch::empty({M, N}, x.options());
    auto x_bf16 = reinterpret_cast<const __nv_bfloat16*>(x.data_ptr());
    auto w_q_ptr = w_q.data_ptr<unsigned char>();
    auto scales_bf16 = reinterpret_cast<const __nv_bfloat16*>(scales.data_ptr());
    auto zeros_bf16 = reinterpret_cast<const __nv_bfloat16*>(zeros.data_ptr());
    auto y_bf16 = reinterpret_cast<__nv_bfloat16*>(y.data_ptr());

    int BLOCK_N = 128;
    dim3 grid((N + BLOCK_N - 1) / BLOCK_N, M, 1);
    dim3 block(BLOCK_N, 1, 1);
    w4a16_kernel<<<grid, block>>>(
        x_bf16, w_q_ptr, scales_bf16, zeros_bf16, y_bf16, M, N, K, n_groups);
    return y;
}
"""


class Model(nn.Module):
    def __init__(self, M: int, N: int, K: int, group_size: int = GROUP_SIZE):
        super().__init__()
        assert K % group_size == 0
        assert K % 2 == 0
        self.M, self.N, self.K = M, N, K
        self.group_size = group_size
        n_groups = K // group_size

        torch.manual_seed(0xC0DE ^ (M * 1315423911 + N * 2654435761 + K))
        w_full = torch.randn(K, N, dtype=torch.float32) * 0.02

        w_g = w_full.view(n_groups, group_size, N)
        w_min = w_g.min(dim=1, keepdim=True).values
        w_max = w_g.max(dim=1, keepdim=True).values
        scales = (w_max - w_min).clamp_min(1e-8) / 15.0
        zeros = (-w_min / scales).round().clamp(0, 15)
        w_q = ((w_g / scales) + zeros).round().clamp(0, 15).

... (973 more chars)
tool
stdout (24 chars)
Wrote file successfully.
assistant
in 103out 1681cache_r 101664cache_w 0
assistant
bash
args
{
  "command": "<2476 chars \u2014 see below>",
  "description": "Test pure CUDA approach",
  "timeout": 60000
}
command (2476 chars)
python -c "
import torch
src = '''
#include <torch/extension.h>
#include <cuda_bf16.h>

__global__
void w4a16_kernel(
    const __nv_bfloat16* __restrict__ x,
    const unsigned char* __restrict__ w_q,
    const __nv_bfloat16* __restrict__ scales,
    const __nv_bfloat16* __restrict__ zeros,
    __nv_bfloat16* __restrict__ y,
    int M, int N, int K, int n_groups
) {
    int n = blockIdx.x * blockDim.x + threadIdx.x;
    int m = blockIdx.y;
    if (n >= N || m >= M) return;
    float acc = 0.0f;
    for (int g = 0; g < n_groups; ++g) {
        int k_base = g * 128;
        __nv_bfloat16 sc = scales[g * N + n];
        __nv_bfloat16 ze = zeros[g * N + n];
        float scale = __bfloat162float(sc);
        float zero = __bfloat162float(ze);
        for (int kk = 0; kk < 128; kk += 2) {
            int k_even = k_base + kk;
            int k_odd = k_base + kk + 1;
            int w_row = k_even >> 1;
            unsigned char w_p = w_q[w_row * N + n];
            unsigned char w_e = w_p & 0xF;
            unsigned char w_o = (w_p >> 4) & 0xF;
            float w_deq_e = ((float)w_e - zero) * scale;
            float w_deq_o = ((float)w_o - zero) * scale;
            float x_e = __bfloat162float(x[m * K + k_even]);
            float x_o = __bfloat162float(x[m * K + k_odd]);
            acc += x_e * w_deq_e;
            acc += x_o * w_deq_o;
        }
    }
    y[m * N + n] = __float2bfloat16(acc);
}

torch::Tensor w4a16_kernel_py(
    const torch::Tensor& x,
    const torch::Tensor& w_q,
    const torch::Tensor& scales,
    const torch::Tensor& zeros,
    int M, int N, int K, int n_groups
) {
    torch::Tensor y = torch::empty({M, N}, x.options());
    auto x_bf16 = reinterpret_cast<const __nv_bfloat16*>(x.data_ptr());
    auto w_q_ptr = w_q.data_ptr<unsigned char>();
    auto scales_bf16 = reinterpret_cast<const __nv_bfloat16*>(scales.data_ptr());
    auto zeros_bf16 = reinterpret_cast<const __nv_bfloat16*>(zeros.data_ptr());
    auto y_bf16 = reinterpret_cast<__nv_bfloat16*>(y.data_ptr());
    int BLOCK_N = 128;
    dim3 grid((N + BLOCK_N - 1) / BLOCK_N, M, 1);
    dim3 block(BLOCK_N, 1, 1);
    w4a16_kernel<<<grid, block>>>(
        x_bf16, w_q_ptr, scales_bf16, zeros_bf16, y_bf16, M, N, K, n_groups);
    return y;
}
'''
import torch.utils.cpp_extension as ext
m = ext.load_inline(
    name='w4a16_test3',
    cpp_sources='',
    cuda_sources=src,
    extra_cuda_cflags=['--use_fast_math', '-O3'],
)
print(type(m), repr(m)[:200])
" 2>&1
tool
stdout (1069 chars)
Traceback (most recent call last):
  File "<string>", line 66, in <module>
  File "/home/infatoshi/.local/lib/python3.12/site-packages/torch/utils/cpp_extension.py", line 2174, in load_inline
    return _jit_compile(
           ^^^^^^^^^^^^^
  File "/home/infatoshi/.local/lib/python3.12/site-packages/torch/utils/cpp_extension.py", line 2294, in _jit_compile
    return _import_module_from_library(name, build_directory, is_python_module)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/infatoshi/.local/lib/python3.12/site-packages/torch/utils/cpp_extension.py", line 2812, in _import_module_from_library
    module = importlib.util.module_from_spec(spec)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "<frozen importlib._bootstrap>", line 813, in module_from_spec
  File "<frozen importlib._bootstrap_external>", line 1289, in create_module
  File "<frozen importlib._bootstrap>", line 488, in _call_with_frames_removed
ImportError: dynamic module does not define module export function (PyInit_w4a16_test3)
assistant
in 1718out 849cache_r 101760cache_w 0
assistant
bash
args
{
  "command": "<2732 chars \u2014 see below>",
  "description": "Test CUDA + minimal cpp",
  "timeout": 60000
}
command (2732 chars)
python -c "
import torch
cuda_src = '''
#include <torch/extension.h>
#include <cuda_bf16.h>

__global__
void w4a16_kernel(
    const __nv_bfloat16* __restrict__ x,
    const unsigned char* __restrict__ w_q,
    const __nv_bfloat16* __restrict__ scales,
    const __nv_bfloat16* __restrict__ zeros,
    __nv_bfloat16* __restrict__ y,
    int M, int N, int K, int n_groups
) {
    int n = blockIdx.x * blockDim.x + threadIdx.x;
    int m = blockIdx.y;
    if (n >= N || m >= M) return;
    float acc = 0.0f;
    for (int g = 0; g < n_groups; ++g) {
        int k_base = g * 128;
        __nv_bfloat16 sc = scales[g * N + n];
        __nv_bfloat16 ze = zeros[g * N + n];
        float scale = __bfloat162float(sc);
        float zero = __bfloat162float(ze);
        for (int kk = 0; kk < 128; kk += 2) {
            int k_even = k_base + kk;
            int k_odd = k_base + kk + 1;
            int w_row = k_even >> 1;
            unsigned char w_p = w_q[w_row * N + n];
            unsigned char w_e = w_p & 0xF;
            unsigned char w_o = (w_p >> 4) & 0xF;
            float w_deq_e = ((float)w_e - zero) * scale;
            float w_deq_o = ((float)w_o - zero) * scale;
            float x_e = __bfloat162float(x[m * K + k_even]);
            float x_o = __bfloat162float(x[m * K + k_odd]);
            acc += x_e * w_deq_e;
            acc += x_o * w_deq_o;
        }
    }
    y[m * N + n] = __float2bfloat16(acc);
}

torch::Tensor w4a16_kernel_py(
    const torch::Tensor& x,
    const torch::Tensor& w_q,
    const torch::Tensor& scales,
    const torch::Tensor& zeros,
    int M, int N, int K, int n_groups
) {
    torch::Tensor y = torch::empty({M, N}, x.options());
    auto x_bf16 = reinterpret_cast<const __nv_bfloat16*>(x.data_ptr());
    auto w_q_ptr = w_q.data_ptr<unsigned char>();
    auto scales_bf16 = reinterpret_cast<const __nv_bfloat16*>(scales.data_ptr());
    auto zeros_bf16 = reinterpret_cast<const __nv_bfloat16*>(zeros.data_ptr());
    auto y_bf16 = reinterpret_cast<__nv_bfloat16*>(y.data_ptr());
    int BLOCK_N = 128;
    dim3 grid((N + BLOCK_N - 1) / BLOCK_N, M, 1);
    dim3 block(BLOCK_N, 1, 1);
    w4a16_kernel<<<grid, block>>>(
        x_bf16, w_q_ptr, scales_bf16, zeros_bf16, y_bf16, M, N, K, n_groups);
    return y;
}
'''
cpp_src = '''
#include <torch/extension.h>
torch::Tensor w4a16_kernel_py(
    const torch::Tensor& x,
    const torch::Tensor& w_q,
    const torch::Tensor& scales,
    const torch::Tensor& zeros,
    int M, int N, int K, int n_groups);
'''
import torch.utils.cpp_extension as ext
m = ext.load_inline(
    name='w4a16_test3',
    cpp_sources=cpp_src,
    cuda_sources=cuda_src,
    extra_cuda_cflags=['--use_fast_math', '-O3'],
)
print(type(m), repr(m)[:200])
" 2>&1
tool
stdout (1069 chars)
Traceback (most recent call last):
  File "<string>", line 75, in <module>
  File "/home/infatoshi/.local/lib/python3.12/site-packages/torch/utils/cpp_extension.py", line 2174, in load_inline
    return _jit_compile(
           ^^^^^^^^^^^^^
  File "/home/infatoshi/.local/lib/python3.12/site-packages/torch/utils/cpp_extension.py", line 2294, in _jit_compile
    return _import_module_from_library(name, build_directory, is_python_module)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/infatoshi/.local/lib/python3.12/site-packages/torch/utils/cpp_extension.py", line 2812, in _import_module_from_library
    module = importlib.util.module_from_spec(spec)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "<frozen importlib._bootstrap>", line 813, in module_from_spec
  File "<frozen importlib._bootstrap_external>", line 1289, in create_module
  File "<frozen importlib._bootstrap>", line 488, in _call_with_frames_removed
ImportError: dynamic module does not define module export function (PyInit_w4a16_test3)
assistant
in 1144out 911cache_r 103456cache_w 0
assistant
bash
args
{
  "command": "<219 chars \u2014 see below>",
  "description": "Check load_inline signature"
}
command (219 chars)
python -c "
import torch.utils.cpp_extension as ext
print(ext.load_inline.__doc__)
import inspect
sig = inspect.signature(ext.load_inline)
for p in sig.parameters.values():
    print(p.name, '=', repr(p.default))
" 2>&1
tool
stdout (5909 chars) — TRUNCATED
Load a PyTorch C++ extension just-in-time (JIT) from string sources.

    This function behaves exactly like :func:`load`, but takes its sources as
    strings rather than filenames. These strings are stored to files in the
    build directory, after which the behavior of :func:`load_inline` is
    identical to :func:`load`.

    See `the
    tests <https://github.com/pytorch/pytorch/blob/master/test/test_cpp_extensions_jit.py>`_
    for good examples of using this function.

    Sources may omit two required parts of a typical non-inline C++ extension:
    the necessary header includes, as well as the (pybind11) binding code. More
    precisely, strings passed to ``cpp_sources`` are first concatenated into a
    single ``.cpp`` file. This file is then prepended with ``#include
    <torch/extension.h>``

    Furthermore, if the ``functions`` argument is supplied, bindings will be
    automatically generated for each function specified. ``functions`` can
    either be a list of function names, or a dictionary mapping from function
    names to docstrings. If a list is given, the name of each function is used
    as its docstring.

    The sources in ``cuda_sources`` are concatenated into a separate ``.cu``
    file and  prepended with ``torch/types.h``, ``cuda.h`` and
    ``cuda_runtime.h`` includes. The ``.cpp`` and ``.cu`` files are compiled
    separately, but ultimately linked into a single library. Note that no
    bindings are generated for functions in ``cuda_sources`` 

... (4409 more chars)
assistant
in 1220out -65cache_r 104576cache_w 0
assistant
bash
args
{
  "command": "<2765 chars \u2014 see below>",
  "description": "Test with cpp declaration + cuda definition",
  "timeout": 60000
}
command (2765 chars)
python -c "
import torch.utils.cpp_extension as ext
cuda_src = '''
#include <torch/extension.h>
#include <cuda_bf16.h>

__global__
void w4a16_kernel(
    const __nv_bfloat16* __restrict__ x,
    const unsigned char* __restrict__ w_q,
    const __nv_bfloat16* __restrict__ scales,
    const __nv_bfloat16* __restrict__ zeros,
    __nv_bfloat16* __restrict__ y,
    int M, int N, int K, int n_groups
) {
    int n = blockIdx.x * blockDim.x + threadIdx.x;
    int m = blockIdx.y;
    if (n >= N || m >= M) return;
    float acc = 0.0f;
    for (int g = 0; g < n_groups; ++g) {
        int k_base = g * 128;
        __nv_bfloat16 sc = scales[g * N + n];
        __nv_bfloat16 ze = zeros[g * N + n];
        float scale = __bfloat162float(sc);
        float zero = __bfloat162float(ze);
        for (int kk = 0; kk < 128; kk += 2) {
            int k_even = k_base + kk;
            int k_odd = k_base + kk + 1;
            int w_row = k_even >> 1;
            unsigned char w_p = w_q[w_row * N + n];
            unsigned char w_e = w_p & 0xF;
            unsigned char w_o = (w_p >> 4) & 0xF;
            float w_deq_e = ((float)w_e - zero) * scale;
            float w_deq_o = ((float)w_o - zero) * scale;
            float x_e = __bfloat162float(x[m * K + k_even]);
            float x_o = __bfloat162float(x[m * K + k_odd]);
            acc += x_e * w_deq_e;
            acc += x_o * w_deq_o;
        }
    }
    y[m * N + n] = __float2bfloat16(acc);
}

torch::Tensor w4a16_kernel_py(
    const torch::Tensor& x,
    const torch::Tensor& w_q,
    const torch::Tensor& scales,
    const torch::Tensor& zeros,
    int M, int N, int K, int n_groups
) {
    torch::Tensor y = torch::empty({M, N}, x.options());
    auto x_bf16 = reinterpret_cast<const __nv_bfloat16*>(x.data_ptr());
    auto w_q_ptr = w_q.data_ptr<unsigned char>();
    auto scales_bf16 = reinterpret_cast<const __nv_bfloat16*>(scales.data_ptr());
    auto zeros_bf16 = reinterpret_cast<const __nv_bfloat16*>(zeros.data_ptr());
    auto y_bf16 = reinterpret_cast<__nv_bfloat16*>(y.data_ptr());
    int BLOCK_N = 128;
    dim3 grid((N + BLOCK_N - 1) / BLOCK_N, M, 1);
    dim3 block(BLOCK_N, 1, 1);
    w4a16_kernel<<<grid, block>>>(
        x_bf16, w_q_ptr, scales_bf16, zeros_bf16, y_bf16, M, N, K, n_groups);
    return y;
}
'''
cpp_src = '''
torch::Tensor w4a16_kernel_py(
    const torch::Tensor& x,
    const torch::Tensor& w_q,
    const torch::Tensor& scales,
    const torch::Tensor& zeros,
    int M, int N, int K, int n_groups);
'''
import torch.utils.cpp_extension as ext
m = ext.load_inline(
    name='w4a16_test4',
    cpp_sources=cpp_src,
    cuda_sources=cuda_src,
    extra_cuda_cflags=['--use_fast_math', '-O3'],
    functions=['w4a16_kernel_py'],
)
print(type(m), repr(m)[:200])
" 2>&1
tool
stdout (126 chars)
<class 'module'> <module 'w4a16_test4' from '/home/infatoshi/.cache/torch_extensions/py312_cu130/w4a16_test4/w4a16_test4.so'>
assistant
in 1435out 923cache_r 105792cache_w 0
assistant
write /home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
diff (28 lines)
--- a//home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
+++ b//home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
@@ -106,6 +106,15 @@
 }
 """
 
+cpp_source = r"""
+torch::Tensor w4a16_kernel_py(
+    const torch::Tensor& x,
+    const torch::Tensor& w_q,
+    const torch::Tensor& scales,
+    const torch::Tensor& zeros,
+    int M, int N, int K, int n_groups);
+"""
+
 
 class Model(nn.Module):
     def __init__(self, M: int, N: int, K: int, group_size: int = GROUP_SIZE):
@@ -165,7 +174,8 @@
 
 w4a16_lib = torch.utils.cpp_extension.load_inline(
     name="w4a16_lib",
-    cpp_sources="",
+    cpp_sources=cpp_source,
     cuda_sources=cuda_source,
     extra_cuda_cflags=["--use_fast_math", "-O3"],
+    functions=["w4a16_kernel_py"],
 )
args
{
  "content": "<5233 chars \u2014 see diff>",
  "filePath": "/home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py"
}
tool
stdout (24 chars)
Wrote file successfully.
assistant
Now I have a working pattern. Let me update solution.py:
assistant
in 1020out 1774cache_r 107200cache_w 0
assistant
bash
args
{
  "command": "python check.py 2>&1",
  "description": "Run check.py",
  "timeout": 180000
}
tool
stdout (5 chars)
PASS
assistant
in 1814out 53cache_r 108192cache_w 0
assistant
todowrite
args
{
  "todos": [
    {
      "content": "Research PTX/CUTLASS W4A16 patterns for SM120",
      "priority": "high",
      "status": "completed"
    },
    {
      "content": "Write fused W4A16 GEMM kernel (solution.py)",
      "priority": "high",
      "status": "completed"
    },
    {
      "content": "Run check.py correctness tests",
      "priority": "high",
      "status": "completed"
    },
    {
      "content": "Profile with benchmark.py and optimize",
      "priority": "high",
      "status": "in_progress"
    },
    {
      "content": "Iterate until PASS with good performance",
      "p

... (55 more chars)
tool
stdout (440 chars)
content: 'Research PTX/CUTLASS W4A16 patterns for SM120'
status: 'completed'
priority: 'high'
content: 'Write fused W4A16 GEMM kernel (solution.py)'
status: 'completed'
priority: 'high'
content: 'Run check.py correctness tests'
status: 'completed'
priority: 'high'
content: 'Profile with benchmark.py and optimize'
status: 'in_progress'
priority: 'high'
content: 'Iterate until PASS with good performance'
status: 'pending'
priority: 'high'
assistant
in 91out 153cache_r 109984cache_w 0
assistant
bash
args
{
  "command": "python benchmark.py 2>&1",
  "description": "Run benchmark to see performance",
  "timeout": 300000
}
tool
stdout (1918 chars) — TRUNCATED
/home/infatoshi/.local/lib/python3.12/site-packages/bitsandbytes/backends/cuda/ops.py:468: FutureWarning: _check_is_size will be removed in a future PyTorch release along with guard_size_oblivious.     Use _check(i >= 0) instead.
  torch._check_is_size(blocksize)
/home/infatoshi/.local/lib/python3.12/site-packages/bitsandbytes/backends/cuda/ops.py:468: FutureWarning: _check_is_size will be removed in a future PyTorch release along with guard_size_oblivious.     Use _check(i >= 0) instead.
  torch._check_is_size(blocksize)
shape=0 variant=eager tflops=0.131 gbps=34.966 ms=0.766
shape=0 variant=compiled tflops=0.668 gbps=177.718 ms=0.151
shape=0 variant=sota tflops=2.348 gbps=624.567 ms=0.043
shape=0 variant=solution tflops=0.422 gbps=112.116 ms=0.239
shape=0 solution_peak_fraction=0.0623
shape=1 variant=eager tflops=4.202 gbps=36.244 ms=0.767
shape=1 variant=compiled tflops=20.668 gbps=178.288 ms=0.156
shape=1 variant=sota tflops=23.432 gbps=202.130 ms=0.137
shape=1 variant=solution tflops=6.584 gbps=56.792 ms=0.489
shape=1 solution_peak_fraction=0.0316
shape=2 variant=eager tflops=31.435 gbps=42.850 ms=0.820
shape=2 variant=compiled tflops=120.519 gbps=164.281 ms=0.214
shape=2 variant=sota tflops=134.633 gbps=183.521 ms=0.191
shape=2 variant=solution tflops=8.151 gbps=11.111 ms=3.161
shape=2 solution_peak_fraction=0.0062
shape=3 variant=eager tflops=0.183 gbps=48.664 ms=0.183
shape=3 variant=compiled tflops=0.504 gbps=134.186 ms=0.067
shape=3 variant=sota tflops=1.273 gbps=33

... (418 more chars)
assistant
in 363out 53cache_r 110048cache_w 0
assistant
write /home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
diff (151 lines)
--- a//home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
+++ b//home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
@@ -36,6 +36,20 @@
 cuda_source = r"""
 #include <torch/extension.h>
 #include <cuda_bf16.h>
+
+#define BLOCK_K 64
+#define BLOCK_N 128
+#define NUM_THREADS 128
+
+template <typename T>
+__device__ __forceinline__ T ld_global(const T* addr) {
+    return *addr;
+}
+
+template <typename T>
+__device__ __forceinline__ void st_global(T* addr, T val) {
+    *addr = val;
+}
 
 __global__
 void w4a16_kernel(
@@ -46,63 +60,77 @@
     __nv_bfloat16* __restrict__ y,
     int M, int N, int K, int n_groups
 ) {
-    int n = blockIdx.x * blockDim.x + threadIdx.x;
+    int n_base = blockIdx.x * BLOCK_N;
     int m = blockIdx.y;
 
-    if (n >= N || m >= M) return;
-
-    float acc = 0.0f;
+    if (m >= M) return;
+
+    __shared__ float s_x[BLOCK_K];
+    __shared__ float s_scale[BLOCK_N];
+    __shared__ float s_zero[BLOCK_N];
+    __shared__ unsigned char s_w[BLOCK_K * BLOCK_N];
+
+    int tid = threadIdx.x;
+
+    float acc[BLOCK_N];
+    #pragma unroll
+    for (int j = 0; j < BLOCK_N; ++j) acc[j] = 0.0f;
 
     for (int g = 0; g < n_groups; ++g) {
-        int k_base = g * 128;
-        __nv_bfloat16 sc = scales[g * N + n];
-        __nv_bfloat16 ze = zeros[g * N + n];
-        float scale = __bfloat162float(sc);
-        float zero = __bfloat162float(ze);
-
-        for (int kk = 0; kk < 128; kk += 2) {
-            int k_even = k_base + kk;
-            int k_odd = k_base + kk + 1;
-            int w_row = k_even >> 1;
-
-            unsigned char w_p = w_q[w_row * N + n];
-            unsigned char w_e = w_p & 0xF;
-            unsigned char w_o = (w_p >> 4) & 0xF;
-
-            float w_deq_e = ((float)w_e - zero) * scale;
-            float w_deq_o = ((float)w_o - zero) * scale;
-
-            float x_e = __bfloat162float(x[m * K + k_even]);
-            float x_o = __bfloat162float(x[m * K + k_odd]);
-
-            acc += x_e * w_deq_e;
-            acc += x_o * w_deq_o;
+        int k_base = g * GROUP_SIZE;
+
+        if (tid < BLOCK_N) {
+            int n = n_base + tid;
+            if (n < N) {
+                __nv_bfloat16 sc = scales[g * N + n];
+                __nv_bfloat16 ze = zeros[g * N + n];
+                s_scale[tid] = __bfloat162float(sc);
+                s_zero[tid] = __bfloat162float(ze);
+            }
+        }
+        __syncthreads();
+
+        for (int k_off = 0; k_off < GROUP_SIZE; k_off += BLOCK_K) {
+            int k_start = k_base + k_off;
+            int k_end = min(k_start + BLOCK_K, K);
+
+            if (tid < (k_end - k_start)) {
+                int k = k_start + tid;
+                s_x[tid] = __bfloat162float(x[m * K + k]);
+
+                int w_row = k >> 1;
+                for (int n = 0; n < BLOCK_N; ++n) {
+                    int nc = n_base + n;
+                    if (nc < N) {
+                        s_w[tid * BLOCK_N + n] = w_q[w_row * N + nc];
+                    }
+                }
+            }
+            __syncthreads();
+
+            if (tid < (k_end - k_start)) {
+                int k = k_start + tid;
+                int w_row = k >> 1;
+                bool k_even = ((k & 1) == 0);
+
+                for (int n = 0; n < BLOCK_N; ++n) {
+                    int nc = n_base + n;
+                    if (nc < N) {
+                        unsigned char wp = s_w[tid * BLOCK_N + n];
+                        unsigned char wv = k_even ? (wp & 0xF) : ((wp >> 4) & 0xF);
+                        float w_dq = ((float)wv - s_zero[n]) * s_scale[n];
+                        acc[n] += s_x[tid] * w_dq;
+                    }
+                }
+            }
+            __syncthreads();
         }
     }
 
-    y[m * N + n] = __float2bfloat16(acc);
-}
-
-torch::Tensor w4a16_kernel_py(
-    const torch::Tensor& x,
-    const torch::Tensor& w_q,
-    const torch::Tensor& scales,
-    const torch::Tensor& zeros,
-    int M, int N, int K, int n_groups
-) {
-    torch::Tensor y = torch::empty({M, N}, x.options());
-    auto x_bf16 = reinterpret_cast<const __nv_bfloat16*>(x.data_ptr());
-    auto w_q_ptr = w_q.data_ptr<unsigned char>();
-    auto scales_bf16 = reinterpret_cast<const __nv_bfloat16*>(scales.data_ptr());
-    auto zeros_bf16 = reinterpret_cast<const __nv_bfloat16*>(zeros.data_ptr());
-    auto y_bf16 = reinterpret_cast<__nv_bfloat16*>(y.data_ptr());
-
-    int BLOCK_N = 128;
-    dim3 grid((N + BLOCK_N - 1) / BLOCK_N, M, 1);
-    dim3 block(BLOCK_N, 1, 1);
-    w4a16_kernel<<<grid, block>>>(
-        x_bf16, w_q_ptr, scales_bf16, zeros_bf16, y_bf16, M, N, K, n_groups);
-    return y;
+    int n = n_base + tid;
+    if (n < N) {
+        y[m * N + n] = __float2bfloat16(acc[tid]);
+    }
 }
 """
 
args
{
  "content": "<5802 chars \u2014 see diff>",
  "filePath": "/home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py"
}
tool
stdout (24 chars)
Wrote file successfully.
assistant
The naive per-thread sequential K loop is too slow. I need to parallelize over K chunks with block reduction. Let me redesign with a proper block-parallel approach:
assistant
in 804out 1789cache_r 110400cache_w 0
assistant
bash
args
{
  "command": "python check.py 2>&1",
  "description": "Run check.py after shared memory version",
  "timeout": 180000
}
tool
stdout (1897 chars) — TRUNCATED
FAIL: import error: Error building extension 'w4a16_lib': [1/2] /usr/local/cuda-13/bin/nvcc -MD -MF cuda.cuda.o.d -DTORCH_EXTENSION_NAME=w4a16_lib -DTORCH_API_INCLUDE_EXTENSION_H -isystem /home/infatoshi/.local/lib/python3.12/site-packages/torch/include -isystem /home/infatoshi/.local/lib/python3.12/site-packages/torch/include/torch/csrc/api/include -isystem /usr/local/cuda-13/include -isystem /usr/include/python3.12 -D__CUDA_NO_HALF_OPERATORS__ -D__CUDA_NO_HALF_CONVERSIONS__ -D__CUDA_NO_BFLOAT16_CONVERSIONS__ -D__CUDA_NO_HALF2_OPERATORS__ --expt-relaxed-constexpr -gencode=arch=compute_120,code=compute_120 -gencode=arch=compute_120,code=sm_120 --compiler-options '-fPIC' --use_fast_math -O3 -std=c++17 -c /home/infatoshi/.cache/torch_extensions/py312_cu130/w4a16_lib/cuda.cu -o cuda.cuda.o 
FAILED: cuda.cuda.o 
/usr/local/cuda-13/bin/nvcc -MD -MF cuda.cuda.o.d -DTORCH_EXTENSION_NAME=w4a16_lib -DTORCH_API_INCLUDE_EXTENSION_H -isystem /home/infatoshi/.local/lib/python3.12/site-packages/torch/include -isystem /home/infatoshi/.local/lib/python3.12/site-packages/torch/include/torch/csrc/api/include -isystem /usr/local/cuda-13/include -isystem /usr/include/python3.12 -D__CUDA_NO_HALF_OPERATORS__ -D__CUDA_NO_HALF_CONVERSIONS__ -D__CUDA_NO_BFLOAT16_CONVERSIONS__ -D__CUDA_NO_HALF2_OPERATORS__ --expt-relaxed-constexpr -gencode=arch=compute_120,code=compute_120 -gencode=arch=compute_120,code=sm_120 --compiler-options '-fPIC' --use_fast_math -O3 -std=c++17 -c /home/infatoshi/.cache/torch_ex

... (397 more chars)
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in 1881out 54cache_r 111200cache_w 0
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edit /home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
diff (10 lines)
--- a//home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
+++ b//home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
@@ -37,6 +37,7 @@
 #include <torch/extension.h>
 #include <cuda_bf16.h>
 
+#define GROUP_SIZE 128
 #define BLOCK_K 64
 #define BLOCK_N 128
 #define NUM_THREADS 128
args
{
  "filePath": "/home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py",
  "newString": "<133 chars \u2014 see below>",
  "oldString": "<110 chars \u2014 see below>"
}
newString (133 chars)
cuda_source = r"""
#include <torch/extension.h>
#include <cuda_bf16.h>

#define GROUP_SIZE 128
#define BLOCK_K 64
#define BLOCK_N 128
oldString (110 chars)
cuda_source = r"""
#include <torch/extension.h>
#include <cuda_bf16.h>

#define BLOCK_K 64
#define BLOCK_N 128
tool
stdout (26 chars)
Edit applied successfully.
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in 700out 136cache_r 113056cache_w 0
assistant
bash
args
{
  "command": "python check.py 2>&1",
  "description": "Run check.py",
  "timeout": 180000
}
tool
stdout (161 chars)
FAIL: import error: /home/infatoshi/.cache/torch_extensions/py312_cu130/w4a16_lib/w4a16_lib.so: undefined symbol: _Z15w4a16_kernel_pyRKN2at6TensorES2_S2_S2_iiii
assistant
in 181out 54cache_r 113728cache_w 0
assistant
edit /home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
diff (103 lines)
--- a//home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
+++ b//home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
@@ -41,16 +41,6 @@
 #define BLOCK_K 64
 #define BLOCK_N 128
 #define NUM_THREADS 128
-
-template <typename T>
-__device__ __forceinline__ T ld_global(const T* addr) {
-    return *addr;
-}
-
-template <typename T>
-__device__ __forceinline__ void st_global(T* addr, T val) {
-    *addr = val;
-}
 
 __global__
 void w4a16_kernel(
@@ -66,10 +56,11 @@
 
     if (m >= M) return;
 
-    __shared__ float s_x[BLOCK_K];
-    __shared__ float s_scale[BLOCK_N];
-    __shared__ float s_zero[BLOCK_N];
-    __shared__ unsigned char s_w[BLOCK_K * BLOCK_N];
+    extern __shared__ char smem[];
+    float* s_x = (float*)smem;
+    float* s_scale = s_x + BLOCK_K;
+    float* s_zero = s_scale + BLOCK_N;
+    unsigned char* s_w = (unsigned char*)(s_zero + BLOCK_N);
 
     int tid = threadIdx.x;
 
@@ -78,8 +69,6 @@
     for (int j = 0; j < BLOCK_N; ++j) acc[j] = 0.0f;
 
     for (int g = 0; g < n_groups; ++g) {
-        int k_base = g * GROUP_SIZE;
-
         if (tid < BLOCK_N) {
             int n = n_base + tid;
             if (n < N) {
@@ -91,11 +80,12 @@
         }
         __syncthreads();
 
+        int k_base = g * GROUP_SIZE;
         for (int k_off = 0; k_off < GROUP_SIZE; k_off += BLOCK_K) {
             int k_start = k_base + k_off;
-            int k_end = min(k_start + BLOCK_K, K);
-
-            if (tid < (k_end - k_start)) {
+            int k_len = min(BLOCK_K, K - k_start);
+
+            if (tid < k_len) {
                 int k = k_start + tid;
                 s_x[tid] = __bfloat162float(x[m * K + k]);
 
@@ -109,9 +99,8 @@
             }
             __syncthreads();
 
-            if (tid < (k_end - k_start)) {
+            if (tid < k_len) {
                 int k = k_start + tid;
-                int w_row = k >> 1;
                 bool k_even = ((k & 1) == 0);
 
                 for (int n = 0; n < BLOCK_N; ++n) {
@@ -133,6 +122,31 @@
         y[m * N + n] = __float2bfloat16(acc[tid]);
     }
 }
+
+torch::Tensor w4a16_kernel_py(
+    const torch::Tensor& x,
+    const torch::Tensor& w_q,
+    const torch::Tensor& scales,
+    const torch::Tensor& zeros,
+    int M, int N, int K, int n_groups
+) {
+    torch::Tensor y = torch::empty({M, N}, x.options());
+    auto x_bf16 = reinterpret_cast<const __nv_bfloat16*>(x.data_ptr());
+    auto w_q_ptr = w_q.data_ptr<unsigned char>();
+    auto scales_bf16 = reinterpret_cast<const __nv_bfloat16*>(scales.data_ptr());
+    auto zeros_bf16 = reinterpret_cast<const __nv_bfloat16*>(zeros.data_ptr());
+    auto y_bf16 = reinterpret_cast<__nv_bfloat16*>(y.data_ptr());
+
+    int smem_size = (BLOCK_K + BLOCK_N + BLOCK_N + BLOCK_K * BLOCK_N) * sizeof(float);
+    smem_size = (smem_size + 0xFF) & ~0xFF;
+
+    int BLOCKS_N = (N + BLOCK_N - 1) / BLOCK_N;
+    dim3 grid(BLOCKS_N, M, 1);
+    dim3 block(NUM_THREADS, 1, 1);
+    w4a16_kernel<<<grid, block, smem_size>>>(
+        x_bf16, w_q_ptr, scales_bf16, zeros_bf16, y_bf16, M, N, K, n_groups);
+    return y;
+}
 """
 
 cpp_source = r"""
args
{
  "filePath": "/home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py",
  "newString": "<3612 chars \u2014 see below>",
  "oldString": "<2846 chars \u2014 see below>"
}
newString (3612 chars)
cuda_source = r"""
#include <torch/extension.h>
#include <cuda_bf16.h>

#define GROUP_SIZE 128
#define BLOCK_K 64
#define BLOCK_N 128
#define NUM_THREADS 128

__global__
void w4a16_kernel(
    const __nv_bfloat16* __restrict__ x,
    const unsigned char* __restrict__ w_q,
    const __nv_bfloat16* __restrict__ scales,
    const __nv_bfloat16* __restrict__ zeros,
    __nv_bfloat16* __restrict__ y,
    int M, int N, int K, int n_groups
) {
    int n_base = blockIdx.x * BLOCK_N;
    int m = blockIdx.y;

    if (m >= M) return;

    extern __shared__ char smem[];
    float* s_x = (float*)smem;
    float* s_scale = s_x + BLOCK_K;
    float* s_zero = s_scale + BLOCK_N;
    unsigned char* s_w = (unsigned char*)(s_zero + BLOCK_N);

    int tid = threadIdx.x;

    float acc[BLOCK_N];
    #pragma unroll
    for (int j = 0; j < BLOCK_N; ++j) acc[j] = 0.0f;

    for (int g = 0; g < n_groups; ++g) {
        if (tid < BLOCK_N) {
            int n = n_base + tid;
            if (n < N) {
                __nv_bfloat16 sc = scales[g * N + n];
                __nv_bfloat16 ze = zeros[g * N + n];
                s_scale[tid] = __bfloat162float(sc);
                s_zero[tid] = __bfloat162float(ze);
            }
        }
        __syncthreads();

        int k_base = g * GROUP_SIZE;
        for (int k_off = 0; k_off < GROUP_SIZE; k_off += BLOCK_K) {
            int k_start = k_base + k_off;
            int k_len = min(BLOCK_K, K - k_start);

            if (tid < k_len) {
                int k = k_start + tid;
                s_x[tid] = __bfloat162float(x[m * K + k]);

                int w_row = k >> 1;
                for (int n = 0; n < BLOCK_N; ++n) {
                    int nc = n_base + n;
                    if (nc < N) {
                        s_w[tid * BLOCK_N + n] = w_q[w_row * N + nc];
                    }
                }
            }
            __syncthreads();

            if (tid < k_len) {
                int k = k_start + tid;
                bool k_even = ((k & 1) == 0);

                for (int n = 0; n < BLOCK_N; ++n) {
                    int nc = n_base + n;
                    if (nc < N) {
                        unsigned char wp = s_w[tid * BLOCK_N + n];
                        unsigned char wv = k_even ? (wp & 0xF) : ((wp >> 4) & 0xF);
                        float w_dq = ((float)wv - s_zero[n]) * s_scale[n];
                        acc[n] += s_x[tid] * w_dq;
                    }
                }
            }
            __syncthreads();
        }
    }

    int n = n_base + tid;
    if (n < N) {
        y[m * N + n] = __float2bfloat16(acc[tid]);
    }
}

torch::Tensor w4a16_kernel_py(
    const torch::Tensor& x,
    const torch::Tensor& w_q,
    const torch::Tensor& scales,
    const torch::Tensor& zeros,
    int M, int N, int K, int n_groups
) {
    torch::Tensor y = torch::empty({M, N}, x.options());
    auto x_bf16 = reinterpret_cast<const __nv_bfloat16*>(x.data_ptr());
    auto w_q_ptr = w_q.data_ptr<unsigned char>();
    auto scales_bf16 = reinterpret_cast<const __nv_bfloat16*>(scales.data_ptr());
    auto zeros_bf16 = reinterpret_cast<const __nv_bfloat16*>(zeros.data_ptr());
    auto y_bf16 = reinterpret_cast<__nv_bfloat16*>(y.data_ptr());

    int smem_size = (BLOCK_K + BLOCK_N + BLOCK_N + BLOCK_K * BLOCK_N) * sizeof(float);
    smem_size = (smem_size + 0xFF) & ~0xFF;

    int BLOCKS_N = (N + BLOCK_N - 1) / BLOCK_N;
    dim3 grid(BLOCKS_N, M, 1);
    dim3 block(NUM_THREADS, 1, 1);
    w4a16_kernel<<<grid, block, smem_size>>>(
        x_bf16, w_q_ptr, scales_bf16, zeros_bf16, y_bf16, M, N, K, n_groups);
    return y;
}
"""
oldString (2846 chars)
cuda_source = r"""
#include <torch/extension.h>
#include <cuda_bf16.h>

#define GROUP_SIZE 128
#define BLOCK_K 64
#define BLOCK_N 128
#define NUM_THREADS 128

template <typename T>
__device__ __forceinline__ T ld_global(const T* addr) {
    return *addr;
}

template <typename T>
__device__ __forceinline__ void st_global(T* addr, T val) {
    *addr = val;
}

__global__
void w4a16_kernel(
    const __nv_bfloat16* __restrict__ x,
    const unsigned char* __restrict__ w_q,
    const __nv_bfloat16* __restrict__ scales,
    const __nv_bfloat16* __restrict__ zeros,
    __nv_bfloat16* __restrict__ y,
    int M, int N, int K, int n_groups
) {
    int n_base = blockIdx.x * BLOCK_N;
    int m = blockIdx.y;

    if (m >= M) return;

    __shared__ float s_x[BLOCK_K];
    __shared__ float s_scale[BLOCK_N];
    __shared__ float s_zero[BLOCK_N];
    __shared__ unsigned char s_w[BLOCK_K * BLOCK_N];

    int tid = threadIdx.x;

    float acc[BLOCK_N];
    #pragma unroll
    for (int j = 0; j < BLOCK_N; ++j) acc[j] = 0.0f;

    for (int g = 0; g < n_groups; ++g) {
        int k_base = g * GROUP_SIZE;

        if (tid < BLOCK_N) {
            int n = n_base + tid;
            if (n < N) {
                __nv_bfloat16 sc = scales[g * N + n];
                __nv_bfloat16 ze = zeros[g * N + n];
                s_scale[tid] = __bfloat162float(sc);
                s_zero[tid] = __bfloat162float(ze);
            }
        }
        __syncthreads();

        for (int k_off = 0; k_off < GROUP_SIZE; k_off += BLOCK_K) {
            int k_start = k_base + k_off;
            int k_end = min(k_start + BLOCK_K, K);

            if (tid < (k_end - k_start)) {
                int k = k_start + tid;
                s_x[tid] = __bfloat162float(x[m * K + k]);

                int w_row = k >> 1;
                for (int n = 0; n < BLOCK_N; ++n) {
                    int nc = n_base + n;
                    if (nc < N) {
                        s_w[tid * BLOCK_N + n] = w_q[w_row * N + nc];
                    }
                }
            }
            __syncthreads();

            if (tid < (k_end - k_start)) {
                int k = k_start + tid;
                int w_row = k >> 1;
                bool k_even = ((k & 1) == 0);

                for (int n = 0; n < BLOCK_N; ++n) {
                    int nc = n_base + n;
                    if (nc < N) {
                        unsigned char wp = s_w[tid * BLOCK_N + n];
                        unsigned char wv = k_even ? (wp & 0xF) : ((wp >> 4) & 0xF);
                        float w_dq = ((float)wv - s_zero[n]) * s_scale[n];
                        acc[n] += s_x[tid] * w_dq;
                    }
                }
            }
            __syncthreads();
        }
    }

    int n = n_base + tid;
    if (n < N) {
        y[m * N + n] = __float2bfloat16(acc[tid]);
    }
}
"""
tool
stdout (26 chars)
Edit applied successfully.
assistant
in 147out 1983cache_r 113888cache_w 0
assistant
edit /home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
diff (10 lines)
--- a//home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
+++ b//home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
@@ -1,7 +1,7 @@
     int BLOCKS_N = (N + BLOCK_N - 1) / BLOCK_N;
     dim3 grid(BLOCKS_N, M, 1);
     dim3 block(NUM_THREADS, 1, 1);
-    w4a16_kernel<<<grid, block>>>(
+    w4a16_kernel<<<grid, block, smem_size>>>(
         x_bf16, w_q_ptr, scales_bf16, zeros_bf16, y_bf16, M, N, K, n_groups);
     return y;
 }
args
{
  "filePath": "/home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py",
  "newString": "<253 chars \u2014 see below>",
  "oldString": "<242 chars \u2014 see below>"
}
newString (253 chars)
    int BLOCKS_N = (N + BLOCK_N - 1) / BLOCK_N;
    dim3 grid(BLOCKS_N, M, 1);
    dim3 block(NUM_THREADS, 1, 1);
    w4a16_kernel<<<grid, block, smem_size>>>(
        x_bf16, w_q_ptr, scales_bf16, zeros_bf16, y_bf16, M, N, K, n_groups);
    return y;
}
oldString (242 chars)
    int BLOCKS_N = (N + BLOCK_N - 1) / BLOCK_N;
    dim3 grid(BLOCKS_N, M, 1);
    dim3 block(NUM_THREADS, 1, 1);
    w4a16_kernel<<<grid, block>>>(
        x_bf16, w_q_ptr, scales_bf16, zeros_bf16, y_bf16, M, N, K, n_groups);
    return y;
}
tool
stdout (26 chars)
Edit applied successfully.
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in 2021out 237cache_r 114016cache_w 0
assistant
bash
args
{
  "command": "python check.py 2>&1",
  "description": "Run check.py",
  "timeout": 180000
}
tool
stdout (117 chars)
FAIL: shape 0 {'M': 1, 'N': 12288, 'K': 4096} seed 42: tolerance exceeded: max_abs_diff=4.73828 (atol=0.1, rtol=0.1)
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in 290out 54cache_r 116032cache_w 0
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write /home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
diff (131 lines)
--- a//home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
+++ b//home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
@@ -37,11 +37,6 @@
 #include <torch/extension.h>
 #include <cuda_bf16.h>
 
-#define GROUP_SIZE 128
-#define BLOCK_K 64
-#define BLOCK_N 128
-#define NUM_THREADS 128
-
 __global__
 void w4a16_kernel(
     const __nv_bfloat16* __restrict__ x,
@@ -51,76 +46,41 @@
     __nv_bfloat16* __restrict__ y,
     int M, int N, int K, int n_groups
 ) {
-    int n_base = blockIdx.x * BLOCK_N;
+    int n = blockIdx.x * blockDim.x + threadIdx.x;
     int m = blockIdx.y;
 
-    if (m >= M) return;
+    if (n >= N || m >= M) return;
 
-    extern __shared__ char smem[];
-    float* s_x = (float*)smem;
-    float* s_scale = s_x + BLOCK_K;
-    float* s_zero = s_scale + BLOCK_N;
-    unsigned char* s_w = (unsigned char*)(s_zero + BLOCK_N);
-
-    int tid = threadIdx.x;
-
-    float acc[BLOCK_N];
-    #pragma unroll
-    for (int j = 0; j < BLOCK_N; ++j) acc[j] = 0.0f;
+    float acc = 0.0f;
 
     for (int g = 0; g < n_groups; ++g) {
-        if (tid < BLOCK_N) {
-            int n = n_base + tid;
-            if (n < N) {
-                __nv_bfloat16 sc = scales[g * N + n];
-                __nv_bfloat16 ze = zeros[g * N + n];
-                s_scale[tid] = __bfloat162float(sc);
-                s_zero[tid] = __bfloat162float(ze);
-            }
-        }
-        __syncthreads();
+        int k_base = g * 128;
+        __nv_bfloat16 sc = scales[g * N + n];
+        __nv_bfloat16 ze = zeros[g * N + n];
+        float scale = __bfloat162float(sc);
+        float zero = __bfloat162float(ze);
 
-        int k_base = g * GROUP_SIZE;
-        for (int k_off = 0; k_off < GROUP_SIZE; k_off += BLOCK_K) {
-            int k_start = k_base + k_off;
-            int k_len = min(BLOCK_K, K - k_start);
+        for (int kk = 0; kk < 128; kk += 2) {
+            int k_even = k_base + kk;
+            int k_odd = k_base + kk + 1;
+            int w_row = k_even >> 1;
 
-            if (tid < k_len) {
-                int k = k_start + tid;
-                s_x[tid] = __bfloat162float(x[m * K + k]);
+            unsigned char w_p = w_q[w_row * N + n];
+            unsigned char w_e = w_p & 0xF;
+            unsigned char w_o = (w_p >> 4) & 0xF;
 
-                int w_row = k >> 1;
-                for (int n = 0; n < BLOCK_N; ++n) {
-                    int nc = n_base + n;
-                    if (nc < N) {
-                        s_w[tid * BLOCK_N + n] = w_q[w_row * N + nc];
-                    }
-                }
-            }
-            __syncthreads();
+            float w_deq_e = ((float)w_e - zero) * scale;
+            float w_deq_o = ((float)w_o - zero) * scale;
 
-            if (tid < k_len) {
-                int k = k_start + tid;
-                bool k_even = ((k & 1) == 0);
+            float x_e = __bfloat162float(x[m * K + k_even]);
+            float x_o = __bfloat162float(x[m * K + k_odd]);
 
-                for (int n = 0; n < BLOCK_N; ++n) {
-                    int nc = n_base + n;
-                    if (nc < N) {
-                        unsigned char wp = s_w[tid * BLOCK_N + n];
-                        unsigned char wv = k_even ? (wp & 0xF) : ((wp >> 4) & 0xF);
-                        float w_dq = ((float)wv - s_zero[n]) * s_scale[n];
-                        acc[n] += s_x[tid] * w_dq;
-                    }
-                }
-            }
-            __syncthreads();
+            acc += x_e * w_deq_e;
+            acc += x_o * w_deq_o;
         }
     }
 
-    int n = n_base + tid;
-    if (n < N) {
-        y[m * N + n] = __float2bfloat16(acc[tid]);
-    }
+    y[m * N + n] = __float2bfloat16(acc);
 }
 
 torch::Tensor w4a16_kernel_py(
@@ -137,13 +97,10 @@
     auto zeros_bf16 = reinterpret_cast<const __nv_bfloat16*>(zeros.data_ptr());
     auto y_bf16 = reinterpret_cast<__nv_bfloat16*>(y.data_ptr());
 
-    int smem_size = (BLOCK_K + BLOCK_N + BLOCK_N + BLOCK_K * BLOCK_N) * sizeof(float);
-    smem_size = (smem_size + 0xFF) & ~0xFF;
-
-    int BLOCKS_N = (N + BLOCK_N - 1) / BLOCK_N;
-    dim3 grid(BLOCKS_N, M, 1);
-    dim3 block(NUM_THREADS, 1, 1);
-    w4a16_kernel<<<grid, block, smem_size>>>(
+    int BLOCK_N = 128;
+    dim3 grid((N + BLOCK_N - 1) / BLOCK_N, M, 1);
+    dim3 block(BLOCK_N, 1, 1);
+    w4a16_kernel<<<grid, block>>>(
         x_bf16, w_q_ptr, scales_bf16, zeros_bf16, y_bf16, M, N, K, n_groups);
     return y;
 }
args
{
  "content": "<5233 chars \u2014 see diff>",
  "filePath": "/home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py"
}
tool
stdout (24 chars)
Wrote file successfully.
assistant
in 156out 1747cache_r 116288cache_w 0
assistant
bash
args
{
  "command": "python check.py 2>&1",
  "description": "Verify simple kernel is correct",
  "timeout": 180000
}
tool
stdout (5 chars)
PASS
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in 1814out 45cache_r 116416cache_w 0
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write /home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
diff (142 lines)
--- a//home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
+++ b//home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
@@ -36,6 +36,12 @@
 cuda_source = r"""
 #include <torch/extension.h>
 #include <cuda_bf16.h>
+
+#define GROUP_SIZE 128
+#define BLOCK_K 64
+#define BLOCK_N 128
+#define NUM_THREADS 128
+#define WARP_SIZE 32
 
 __global__
 void w4a16_kernel(
@@ -46,41 +52,80 @@
     __nv_bfloat16* __restrict__ y,
     int M, int N, int K, int n_groups
 ) {
-    int n = blockIdx.x * blockDim.x + threadIdx.x;
+    int n_base = blockIdx.x * BLOCK_N;
     int m = blockIdx.y;
 
-    if (n >= N || m >= M) return;
-
-    float acc = 0.0f;
+    if (m >= M) return;
+    if (n_base >= N) return;
+
+    extern __shared__ char smem[];
+    float* s_scale = (float*)smem;
+    float* s_zero = s_scale + BLOCK_N;
+    float* s_x = s_zero + BLOCK_N;
+    unsigned char* s_w = (unsigned char*)(s_x + BLOCK_K);
+
+    int tid = threadIdx.x;
+    int wid = tid / WARP_SIZE;
+    int lane = tid % WARP_SIZE;
+
+    float acc[4];
+    #pragma unroll
+    for (int j = 0; j < 4; ++j) acc[j] = 0.0f;
 
     for (int g = 0; g < n_groups; ++g) {
-        int k_base = g * 128;
-        __nv_bfloat16 sc = scales[g * N + n];
-        __nv_bfloat16 ze = zeros[g * N + n];
-        float scale = __bfloat162float(sc);
-        float zero = __bfloat162float(ze);
-
-        for (int kk = 0; kk < 128; kk += 2) {
-            int k_even = k_base + kk;
-            int k_odd = k_base + kk + 1;
-            int w_row = k_even >> 1;
-
-            unsigned char w_p = w_q[w_row * N + n];
-            unsigned char w_e = w_p & 0xF;
-            unsigned char w_o = (w_p >> 4) & 0xF;
-
-            float w_deq_e = ((float)w_e - zero) * scale;
-            float w_deq_o = ((float)w_o - zero) * scale;
-
-            float x_e = __bfloat162float(x[m * K + k_even]);
-            float x_o = __bfloat162float(x[m * K + k_odd]);
-
-            acc += x_e * w_deq_e;
-            acc += x_o * w_deq_o;
+        if (lane < BLOCK_N / 4) {
+            int n = n_base + lane * 4;
+            if (n < N) {
+                __nv_bfloat16 sc = scales[g * N + n];
+                __nv_bfloat16 ze = zeros[g * N + n];
+                s_scale[lane * 4] = __bfloat162float(sc);
+                s_zero[lane * 4] = __bfloat162float(ze);
+            }
+        }
+        __syncthreads();
+
+        int k_base = g * GROUP_SIZE;
+        for (int k_off = 0; k_off < GROUP_SIZE; k_off += BLOCK_K) {
+            int k_start = k_base + k_off;
+            int k_len = min(BLOCK_K, K - k_start);
+
+            if (tid < k_len) {
+                int k = k_start + tid;
+                s_x[tid] = __bfloat162float(x[m * K + k]);
+
+                int w_row = k >> 1;
+                unsigned char wp = w_q[w_row * N + n_base + tid];
+                s_w[tid] = wp;
+            }
+            __syncthreads();
+
+            if (tid < k_len) {
+                int k = k_start + tid;
+                bool k_even = ((k & 1) == 0);
+
+                unsigned char wp = s_w[tid];
+                unsigned char wv = k_even ? (wp & 0xF) : ((wp >> 4) & 0xF);
+
+                #pragma unroll
+                for (int j = 0; j < 4; ++j) {
+                    int nc = lane * 4 + j;
+                    float w_dq = ((float)wv - s_zero[nc]) * s_scale[nc];
+                    acc[j] += s_x[tid] * w_dq;
+                }
+            }
+            __syncthreads();
         }
     }
 
-    y[m * N + n] = __float2bfloat16(acc);
+    if (lane < BLOCK_N / 4) {
+        int n = n_base + lane * 4;
+        #pragma unroll
+        for (int j = 0; j < 4; ++j) {
+            if (n + j < N) {
+                y[m * N + n + j] = __float2bfloat16(acc[j]);
+            }
+        }
+    }
 }
 
 torch::Tensor w4a16_kernel_py(
@@ -97,10 +142,13 @@
     auto zeros_bf16 = reinterpret_cast<const __nv_bfloat16*>(zeros.data_ptr());
     auto y_bf16 = reinterpret_cast<__nv_bfloat16*>(y.data_ptr());
 
-    int BLOCK_N = 128;
-    dim3 grid((N + BLOCK_N - 1) / BLOCK_N, M, 1);
-    dim3 block(BLOCK_N, 1, 1);
-    w4a16_kernel<<<grid, block>>>(
+    int smem_size = (2 * BLOCK_N + BLOCK_K + BLOCK_K) * sizeof(float);
+    smem_size = (smem_size + 0xFF) & ~0xFF;
+
+    int BLOCKS_N = (N + BLOCK_N - 1) / BLOCK_N;
+    dim3 grid(BLOCKS_N, M, 1);
+    dim3 block(NUM_THREADS, 1, 1);
+    w4a16_kernel<<<grid, block, smem_size>>>(
         x_bf16, w_q_ptr, scales_bf16, zeros_bf16, y_bf16, M, N, K, n_groups);
     return y;
 }
args
{
  "content": "<6638 chars \u2014 see diff>",
  "filePath": "/home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py"
}
tool
stdout (24 chars)
Wrote file successfully.
assistant
in 93out 2171cache_r 118208cache_w 0
assistant
write /home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
diff (132 lines)
--- a//home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
+++ b//home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
@@ -40,8 +40,7 @@
 #define GROUP_SIZE 128
 #define BLOCK_K 64
 #define BLOCK_N 128
-#define NUM_THREADS 128
-#define WARP_SIZE 32
+#define THREADS_N 128
 
 __global__
 void w4a16_kernel(
@@ -52,80 +51,42 @@
     __nv_bfloat16* __restrict__ y,
     int M, int N, int K, int n_groups
 ) {
-    int n_base = blockIdx.x * BLOCK_N;
+    int n = blockIdx.x * THREADS_N + threadIdx.x;
     int m = blockIdx.y;
 
-    if (m >= M) return;
-    if (n_base >= N) return;
+    if (n >= N || m >= M) return;
 
-    extern __shared__ char smem[];
-    float* s_scale = (float*)smem;
-    float* s_zero = s_scale + BLOCK_N;
-    float* s_x = s_zero + BLOCK_N;
-    unsigned char* s_w = (unsigned char*)(s_x + BLOCK_K);
-
-    int tid = threadIdx.x;
-    int wid = tid / WARP_SIZE;
-    int lane = tid % WARP_SIZE;
-
-    float acc[4];
-    #pragma unroll
-    for (int j = 0; j < 4; ++j) acc[j] = 0.0f;
+    float acc = 0.0f;
 
     for (int g = 0; g < n_groups; ++g) {
-        if (lane < BLOCK_N / 4) {
-            int n = n_base + lane * 4;
-            if (n < N) {
-                __nv_bfloat16 sc = scales[g * N + n];
-                __nv_bfloat16 ze = zeros[g * N + n];
-                s_scale[lane * 4] = __bfloat162float(sc);
-                s_zero[lane * 4] = __bfloat162float(ze);
-            }
-        }
-        __syncthreads();
+        int k_base = g * GROUP_SIZE;
 
-        int k_base = g * GROUP_SIZE;
-        for (int k_off = 0; k_off < GROUP_SIZE; k_off += BLOCK_K) {
-            int k_start = k_base + k_off;
-            int k_len = min(BLOCK_K, K - k_start);
+        __nv_bfloat16 sc = scales[g * N + n];
+        __nv_bfloat16 ze = zeros[g * N + n];
+        float scale = __bfloat162float(sc);
+        float zero = __bfloat162float(ze);
 
-            if (tid < k_len) {
-                int k = k_start + tid;
-                s_x[tid] = __bfloat162float(x[m * K + k]);
+        for (int k_off = 0; k_off < GROUP_SIZE; k_off += 2) {
+            int k_even = k_base + k_off;
+            int k_odd = k_base + k_off + 1;
+            int w_row = k_even >> 1;
 
-                int w_row = k >> 1;
-                unsigned char wp = w_q[w_row * N + n_base + tid];
-                s_w[tid] = wp;
-            }
-            __syncthreads();
+            unsigned char wp = w_q[w_row * N + n];
+            unsigned char w_even = wp & 0xF;
+            unsigned char w_odd = (wp >> 4) & 0xF;
 
-            if (tid < k_len) {
-                int k = k_start + tid;
-                bool k_even = ((k & 1) == 0);
+            float w_deq_even = ((float)w_even - zero) * scale;
+            float w_deq_odd = ((float)w_odd - zero) * scale;
 
-                unsigned char wp = s_w[tid];
-                unsigned char wv = k_even ? (wp & 0xF) : ((wp >> 4) & 0xF);
+            float x_even = __bfloat162float(x[m * K + k_even]);
+            float x_odd = __bfloat162float(x[m * K + k_odd]);
 
-                #pragma unroll
-                for (int j = 0; j < 4; ++j) {
-                    int nc = lane * 4 + j;
-                    float w_dq = ((float)wv - s_zero[nc]) * s_scale[nc];
-                    acc[j] += s_x[tid] * w_dq;
-                }
-            }
-            __syncthreads();
+            acc += x_even * w_deq_even;
+            acc += x_odd * w_deq_odd;
         }
     }
 
-    if (lane < BLOCK_N / 4) {
-        int n = n_base + lane * 4;
-        #pragma unroll
-        for (int j = 0; j < 4; ++j) {
-            if (n + j < N) {
-                y[m * N + n + j] = __float2bfloat16(acc[j]);
-            }
-        }
-    }
+    y[m * N + n] = __float2bfloat16(acc);
 }
 
 torch::Tensor w4a16_kernel_py(
@@ -142,13 +103,9 @@
     auto zeros_bf16 = reinterpret_cast<const __nv_bfloat16*>(zeros.data_ptr());
     auto y_bf16 = reinterpret_cast<__nv_bfloat16*>(y.data_ptr());
 
-    int smem_size = (2 * BLOCK_N + BLOCK_K + BLOCK_K) * sizeof(float);
-    smem_size = (smem_size + 0xFF) & ~0xFF;
-
-    int BLOCKS_N = (N + BLOCK_N - 1) / BLOCK_N;
-    dim3 grid(BLOCKS_N, M, 1);
-    dim3 block(NUM_THREADS, 1, 1);
-    w4a16_kernel<<<grid, block, smem_size>>>(
+    dim3 grid((N + THREADS_N - 1) / THREADS_N, M, 1);
+    dim3 block(THREADS_N, 1, 1);
+    w4a16_kernel<<<grid, block>>>(
         x_bf16, w_q_ptr, scales_bf16, zeros_bf16, y_bf16, M, N, K, n_groups);
     return y;
 }
args
{
  "content": "<5357 chars \u2014 see diff>",
  "filePath": "/home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py"
}
tool
stdout (24 chars)
Wrote file successfully.
assistant
in 2224out 1755cache_r 118272cache_w 0
assistant
write /home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
diff (48 lines)
--- a//home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
+++ b//home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
@@ -38,9 +38,7 @@
 #include <cuda_bf16.h>
 
 #define GROUP_SIZE 128
-#define BLOCK_K 64
-#define BLOCK_N 128
-#define THREADS_N 128
+#define THREADS_N 256
 
 __global__
 void w4a16_kernel(
@@ -66,23 +64,23 @@
         float scale = __bfloat162float(sc);
         float zero = __bfloat162float(ze);
 
-        for (int k_off = 0; k_off < GROUP_SIZE; k_off += 2) {
-            int k_even = k_base + k_off;
-            int k_odd = k_base + k_off + 1;
+        for (int kk = 0; kk < 128; kk += 2) {
+            int k_even = k_base + kk;
+            int k_odd = k_base + kk + 1;
             int w_row = k_even >> 1;
 
             unsigned char wp = w_q[w_row * N + n];
-            unsigned char w_even = wp & 0xF;
-            unsigned char w_odd = (wp >> 4) & 0xF;
+            unsigned char w_e = wp & 0xF;
+            unsigned char w_o = (wp >> 4) & 0xF;
 
-            float w_deq_even = ((float)w_even - zero) * scale;
-            float w_deq_odd = ((float)w_odd - zero) * scale;
+            float w_deq_e = ((float)w_e - zero) * scale;
+            float w_deq_o = ((float)w_o - zero) * scale;
 
-            float x_even = __bfloat162float(x[m * K + k_even]);
-            float x_odd = __bfloat162float(x[m * K + k_odd]);
+            float x_e = __bfloat162float(x[m * K + k_even]);
+            float x_o = __bfloat162float(x[m * K + k_odd]);
 
-            acc += x_even * w_deq_even;
-            acc += x_odd * w_deq_odd;
+            acc += x_e * w_deq_e;
+            acc += x_o * w_deq_o;
         }
     }
 
args
{
  "content": "<5266 chars \u2014 see diff>",
  "filePath": "/home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py"
}
tool
stdout (24 chars)
Wrote file successfully.
assistant
in 1836out 1756cache_r 120480cache_w 0
assistant
bash
args
{
  "command": "python check.py 2>&1 && python benchmark.py 2>&1",
  "description": "Run check.py and benchmark",
  "timeout": 300000
}
tool
stdout (1923 chars) — TRUNCATED
PASS
/home/infatoshi/.local/lib/python3.12/site-packages/bitsandbytes/backends/cuda/ops.py:468: FutureWarning: _check_is_size will be removed in a future PyTorch release along with guard_size_oblivious.     Use _check(i >= 0) instead.
  torch._check_is_size(blocksize)
/home/infatoshi/.local/lib/python3.12/site-packages/bitsandbytes/backends/cuda/ops.py:468: FutureWarning: _check_is_size will be removed in a future PyTorch release along with guard_size_oblivious.     Use _check(i >= 0) instead.
  torch._check_is_size(blocksize)
shape=0 variant=eager tflops=0.131 gbps=34.954 ms=0.766
shape=0 variant=compiled tflops=0.667 gbps=177.323 ms=0.151
shape=0 variant=sota tflops=2.325 gbps=618.336 ms=0.043
shape=0 variant=solution tflops=0.426 gbps=113.346 ms=0.236
shape=0 solution_peak_fraction=0.0630
shape=1 variant=eager tflops=4.198 gbps=36.212 ms=0.767
shape=1 variant=compiled tflops=20.567 gbps=177.414 ms=0.157
shape=1 variant=sota tflops=23.358 gbps=201.497 ms=0.138
shape=1 variant=solution tflops=6.662 gbps=57.469 ms=0.484
shape=1 solution_peak_fraction=0.0319
shape=2 variant=eager tflops=31.406 gbps=42.811 ms=0.821
shape=2 variant=compiled tflops=120.222 gbps=163.877 ms=0.214
shape=2 variant=sota tflops=134.173 gbps=182.894 ms=0.192
shape=2 variant=solution tflops=8.194 gbps=11.170 ms=3.145
shape=2 solution_peak_fraction=0.0062
shape=3 variant=eager tflops=0.182 gbps=48.541 ms=0.184
shape=3 variant=compiled tflops=0.496 gbps=132.090 ms=0.068
shape=3 variant=sota tflops=1.243 gb

... (423 more chars)
assistant
in 1808out 59cache_r 122304cache_w 0
assistant
write /home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
diff (141 lines)
--- a//home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
+++ b//home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
@@ -38,7 +38,9 @@
 #include <cuda_bf16.h>
 
 #define GROUP_SIZE 128
-#define THREADS_N 256
+#define BLOCK_M 4
+#define BLOCK_N 128
+#define THREADS (BLOCK_M * BLOCK_N)
 
 __global__
 void w4a16_kernel(
@@ -49,42 +51,82 @@
     __nv_bfloat16* __restrict__ y,
     int M, int N, int K, int n_groups
 ) {
-    int n = blockIdx.x * THREADS_N + threadIdx.x;
-    int m = blockIdx.y;
-
-    if (n >= N || m >= M) return;
-
-    float acc = 0.0f;
+    int n_block = blockIdx.x;
+    int m_block = blockIdx.y;
+    int tid = threadIdx.x;
+
+    int n_start = n_block * BLOCK_N;
+    int m_start = m_block * BLOCK_M;
+
+    if (m_start >= M || n_start >= N) return;
+
+    __shared__ float s_x[GROUP_SIZE * BLOCK_M];
+    __shared__ float s_scale[BLOCK_N];
+    __shared__ float s_zero[BLOCK_N];
+
+    float acc[BLOCK_M];
+    #pragma unroll
+    for (int i = 0; i < BLOCK_M; ++i) acc[i] = 0.0f;
 
     for (int g = 0; g < n_groups; ++g) {
+        if (tid < BLOCK_N) {
+            int n = n_start + tid;
+            if (n < N) {
+                __nv_bfloat16 sc = scales[g * N + n];
+                __nv_bfloat16 ze = zeros[g * N + n];
+                s_scale[tid] = __bfloat162float(sc);
+                s_zero[tid] = __bfloat162float(ze);
+            }
+        }
+
         int k_base = g * GROUP_SIZE;
-
-        __nv_bfloat16 sc = scales[g * N + n];
-        __nv_bfloat16 ze = zeros[g * N + n];
-        float scale = __bfloat162float(sc);
-        float zero = __bfloat162float(ze);
-
-        for (int kk = 0; kk < 128; kk += 2) {
+        if (tid < GROUP_SIZE * BLOCK_M) {
+            int kidx = tid / BLOCK_M;
+            int midx = tid % BLOCK_M;
+            int m = m_start + midx;
+            int k = k_base + kidx;
+            if (m < M && k < K) {
+                s_x[kidx * BLOCK_M + midx] = __bfloat162float(x[m * K + k]);
+            }
+        }
+        __syncthreads();
+
+        for (int kk = 0; kk < GROUP_SIZE; kk += 2) {
             int k_even = k_base + kk;
             int k_odd = k_base + kk + 1;
-            int w_row = k_even >> 1;
-
-            unsigned char wp = w_q[w_row * N + n];
-            unsigned char w_e = wp & 0xF;
-            unsigned char w_o = (wp >> 4) & 0xF;
-
-            float w_deq_e = ((float)w_e - zero) * scale;
-            float w_deq_o = ((float)w_o - zero) * scale;
-
-            float x_e = __bfloat162float(x[m * K + k_even]);
-            float x_o = __bfloat162float(x[m * K + k_odd]);
-
-            acc += x_e * w_deq_e;
-            acc += x_o * w_deq_o;
-        }
+
+            #pragma unroll
+            for (int i = 0; i < BLOCK_M; ++i) {
+                int m = m_start + i;
+                if (m < M) {
+                    float x_even_val = s_x[kk * BLOCK_M + i];
+                    float x_odd_val = s_x[(kk + 1) * BLOCK_M + i];
+
+                    int w_row_even = k_even >> 1;
+                    unsigned char wp_even = w_q[w_row_even * N + n_start + tid];
+
+                    unsigned char w_even_lo = wp_even & 0xF;
+                    unsigned char w_odd_lo = (wp_even >> 4) & 0xF;
+
+                    float w_deq_even = ((float)w_even_lo - s_zero[tid]) * s_scale[tid];
+                    float w_deq_odd = ((float)w_odd_lo - s_zero[tid]) * s_scale[tid];
+
+                    acc[i] += x_even_val * w_deq_even;
+                    acc[i] += x_odd_val * w_deq_odd;
+                }
+            }
+        }
+        __syncthreads();
     }
 
-    y[m * N + n] = __float2bfloat16(acc);
+    #pragma unroll
+    for (int i = 0; i < BLOCK_M; ++i) {
+        int m = m_start + i;
+        int n = n_start + tid;
+        if (m < M && n < N) {
+            y[m * N + n] = __float2bfloat16(acc[i]);
+        }
+    }
 }
 
 torch::Tensor w4a16_kernel_py(
@@ -101,9 +143,12 @@
     auto zeros_bf16 = reinterpret_cast<const __nv_bfloat16*>(zeros.data_ptr());
     auto y_bf16 = reinterpret_cast<__nv_bfloat16*>(y.data_ptr());
 
-    dim3 grid((N + THREADS_N - 1) / THREADS_N, M, 1);
-    dim3 block(THREADS_N, 1, 1);
-    w4a16_kernel<<<grid, block>>>(
+    int smem_size = (GROUP_SIZE * BLOCK_M + 2 * BLOCK_N) * sizeof(float);
+    int BLOCKS_N = (N + BLOCK_N - 1) / BLOCK_N;
+    int BLOCKS_M = (M + BLOCK_M - 1) / BLOCK_M;
+    dim3 grid(BLOCKS_N, BLOCKS_M, 1);
+    dim3 block(THREADS, 1, 1);
+    w4a16_kernel<<<grid, block, smem_size>>>(
         x_bf16, w_q_ptr, scales_bf16, zeros_bf16, y_bf16, M, N, K, n_groups);
     return y;
 }
args
{
  "content": "<6847 chars \u2014 see diff>",
  "filePath": "/home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py"
}
tool
stdout (24 chars)
Wrote file successfully.
assistant
in 819out 2227cache_r 124096cache_w 0
assistant
bash
args
{
  "command": "python check.py 2>&1",
  "description": "Check if block-M kernel is correct",
  "timeout": 180000
}
tool
stdout (117 chars)
FAIL: shape 0 {'M': 1, 'N': 12288, 'K': 4096} seed 42: tolerance exceeded: max_abs_diff=8507.53 (atol=0.1, rtol=0.1)
assistant
in 2267out 124cache_r 124896cache_w 0
assistant
write /home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
diff (136 lines)
--- a//home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
+++ b//home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
@@ -38,9 +38,12 @@
 #include <cuda_bf16.h>
 
 #define GROUP_SIZE 128
-#define BLOCK_M 4
-#define BLOCK_N 128
-#define THREADS (BLOCK_M * BLOCK_N)
+#define THREADS_N 256
+#define WARP_SIZE 32
+
+__device__ __forceinline__ float2 bf162float2(__nv_bfloat162 h) {
+    return __nv_bfloat162float(h);
+}
 
 __global__
 void w4a16_kernel(
@@ -51,82 +54,40 @@
     __nv_bfloat16* __restrict__ y,
     int M, int N, int K, int n_groups
 ) {
-    int n_block = blockIdx.x;
-    int m_block = blockIdx.y;
-    int tid = threadIdx.x;
+    int n = blockIdx.x * THREADS_N + threadIdx.x;
+    int m = blockIdx.y;
 
-    int n_start = n_block * BLOCK_N;
-    int m_start = m_block * BLOCK_M;
+    if (n >= N || m >= M) return;
 
-    if (m_start >= M || n_start >= N) return;
-
-    __shared__ float s_x[GROUP_SIZE * BLOCK_M];
-    __shared__ float s_scale[BLOCK_N];
-    __shared__ float s_zero[BLOCK_N];
-
-    float acc[BLOCK_M];
-    #pragma unroll
-    for (int i = 0; i < BLOCK_M; ++i) acc[i] = 0.0f;
+    float acc = 0.0f;
 
     for (int g = 0; g < n_groups; ++g) {
-        if (tid < BLOCK_N) {
-            int n = n_start + tid;
-            if (n < N) {
-                __nv_bfloat16 sc = scales[g * N + n];
-                __nv_bfloat16 ze = zeros[g * N + n];
-                s_scale[tid] = __bfloat162float(sc);
-                s_zero[tid] = __bfloat162float(ze);
-            }
-        }
+        int k_base = g * GROUP_SIZE;
 
-        int k_base = g * GROUP_SIZE;
-        if (tid < GROUP_SIZE * BLOCK_M) {
-            int kidx = tid / BLOCK_M;
-            int midx = tid % BLOCK_M;
-            int m = m_start + midx;
-            int k = k_base + kidx;
-            if (m < M && k < K) {
-                s_x[kidx * BLOCK_M + midx] = __bfloat162float(x[m * K + k]);
-            }
-        }
-        __syncthreads();
+        float scale = __bfloat162float(scales[g * N + n]);
+        float zero = __bfloat162float(zeros[g * N + n]);
 
-        for (int kk = 0; kk < GROUP_SIZE; kk += 2) {
+        for (int kk = 0; kk < 128; kk += 2) {
             int k_even = k_base + kk;
             int k_odd = k_base + kk + 1;
+            int w_row = k_even >> 1;
 
-            #pragma unroll
-            for (int i = 0; i < BLOCK_M; ++i) {
-                int m = m_start + i;
-                if (m < M) {
-                    float x_even_val = s_x[kk * BLOCK_M + i];
-                    float x_odd_val = s_x[(kk + 1) * BLOCK_M + i];
+            unsigned char wp = w_q[w_row * N + n];
+            unsigned char w_even_val = wp & 0xF;
+            unsigned char w_odd_val = (wp >> 4) & 0xF;
 
-                    int w_row_even = k_even >> 1;
-                    unsigned char wp_even = w_q[w_row_even * N + n_start + tid];
+            float w_deq_even = ((float)w_even_val - zero) * scale;
+            float w_deq_odd = ((float)w_odd_val - zero) * scale;
 
-                    unsigned char w_even_lo = wp_even & 0xF;
-                    unsigned char w_odd_lo = (wp_even >> 4) & 0xF;
+            float x_even = __bfloat162float(x[m * K + k_even]);
+            float x_odd = __bfloat162float(x[m * K + k_odd]);
 
-                    float w_deq_even = ((float)w_even_lo - s_zero[tid]) * s_scale[tid];
-                    float w_deq_odd = ((float)w_odd_lo - s_zero[tid]) * s_scale[tid];
-
-                    acc[i] += x_even_val * w_deq_even;
-                    acc[i] += x_odd_val * w_deq_odd;
-                }
-            }
+            acc += x_even * w_deq_even;
+            acc += x_odd * w_deq_odd;
         }
-        __syncthreads();
     }
 
-    #pragma unroll
-    for (int i = 0; i < BLOCK_M; ++i) {
-        int m = m_start + i;
-        int n = n_start + tid;
-        if (m < M && n < N) {
-            y[m * N + n] = __float2bfloat16(acc[i]);
-        }
-    }
+    y[m * N + n] = __float2bfloat16(acc);
 }
 
 torch::Tensor w4a16_kernel_py(
@@ -143,12 +104,9 @@
     auto zeros_bf16 = reinterpret_cast<const __nv_bfloat16*>(zeros.data_ptr());
     auto y_bf16 = reinterpret_cast<__nv_bfloat16*>(y.data_ptr());
 
-    int smem_size = (GROUP_SIZE * BLOCK_M + 2 * BLOCK_N) * sizeof(float);
-    int BLOCKS_N = (N + BLOCK_N - 1) / BLOCK_N;
-    int BLOCKS_M = (M + BLOCK_M - 1) / BLOCK_M;
-    dim3 grid(BLOCKS_N, BLOCKS_M, 1);
-    dim3 block(THREADS, 1, 1);
-    w4a16_kernel<<<grid, block, smem_size>>>(
+    dim3 grid((N + THREADS_N - 1) / THREADS_N, M, 1);
+    dim3 block(THREADS_N, 1, 1);
+    w4a16_kernel<<<grid, block>>>(
         x_bf16, w_q_ptr, scales_bf16, zeros_bf16, y_bf16, M, N, K, n_groups);
     return y;
 }
args
{
  "content": "<5375 chars \u2014 see diff>",
  "filePath": "/home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py"
}
tool
stdout (24 chars)
Wrote file successfully.
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write /home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
diff (14 lines)
--- a//home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
+++ b//home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
@@ -39,11 +39,6 @@
 
 #define GROUP_SIZE 128
 #define THREADS_N 256
-#define WARP_SIZE 32
-
-__device__ __forceinline__ float2 bf162float2(__nv_bfloat162 h) {
-    return __nv_bfloat162float(h);
-}
 
 __global__
 void w4a16_kernel(
args
{
  "content": "<5250 chars \u2014 see diff>",
  "filePath": "/home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py"
}
tool
stdout (24 chars)
Wrote file successfully.
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bash
args
{
  "command": "python check.py 2>&1",
  "description": "Run check.py",
  "timeout": 180000
}
tool
stdout (5 chars)
PASS
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bash
args
{
  "command": "python benchmark.py 2>&1",
  "description": "Run benchmark",
  "timeout": 300000
}
tool
stdout (1918 chars) — TRUNCATED
/home/infatoshi/.local/lib/python3.12/site-packages/bitsandbytes/backends/cuda/ops.py:468: FutureWarning: _check_is_size will be removed in a future PyTorch release along with guard_size_oblivious.     Use _check(i >= 0) instead.
  torch._check_is_size(blocksize)
/home/infatoshi/.local/lib/python3.12/site-packages/bitsandbytes/backends/cuda/ops.py:468: FutureWarning: _check_is_size will be removed in a future PyTorch release along with guard_size_oblivious.     Use _check(i >= 0) instead.
  torch._check_is_size(blocksize)
shape=0 variant=eager tflops=0.132 gbps=34.974 ms=0.765
shape=0 variant=compiled tflops=0.670 gbps=178.153 ms=0.150
shape=0 variant=sota tflops=2.362 gbps=628.084 ms=0.043
shape=0 variant=solution tflops=0.425 gbps=113.093 ms=0.237
shape=0 solution_peak_fraction=0.0628
shape=1 variant=eager tflops=4.198 gbps=36.215 ms=0.767
shape=1 variant=compiled tflops=20.460 gbps=176.494 ms=0.157
shape=1 variant=sota tflops=23.465 gbps=202.413 ms=0.137
shape=1 variant=solution tflops=6.690 gbps=57.709 ms=0.482
shape=1 solution_peak_fraction=0.0321
shape=2 variant=eager tflops=31.419 gbps=42.828 ms=0.820
shape=2 variant=compiled tflops=120.772 gbps=164.626 ms=0.213
shape=2 variant=sota tflops=134.162 gbps=182.878 ms=0.192
shape=2 variant=solution tflops=8.284 gbps=11.292 ms=3.111
shape=2 solution_peak_fraction=0.0063
shape=3 variant=eager tflops=0.183 gbps=48.664 ms=0.183
shape=3 variant=compiled tflops=0.502 gbps=133.672 ms=0.067
shape=3 variant=sota tflops=1.231 gbps=32

... (418 more chars)
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write /home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
diff (548 lines — TRUNCATED)
--- a//home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
+++ b//home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py
@@ -56,30 +56,527 @@
 
     float acc = 0.0f;
 
+    const __nv_bfloat16* x_row = x + m * K;
+
     for (int g = 0; g < n_groups; ++g) {
         int k_base = g * GROUP_SIZE;
 
         float scale = __bfloat162float(scales[g * N + n]);
         float zero = __bfloat162float(zeros[g * N + n]);
 
-        for (int kk = 0; kk < 128; kk += 2) {
-            int k_even = k_base + kk;
-            int k_odd = k_base + kk + 1;
-            int w_row = k_even >> 1;
-
-            unsigned char wp = w_q[w_row * N + n];
-            unsigned char w_even_val = wp & 0xF;
-            unsigned char w_odd_val = (wp >> 4) & 0xF;
-
-            float w_deq_even = ((float)w_even_val - zero) * scale;
-            float w_deq_odd = ((float)w_odd_val - zero) * scale;
-
-            float x_even = __bfloat162float(x[m * K + k_even]);
-            float x_odd = __bfloat162float(x[m * K + k_odd]);
-
-            acc += x_even * w_deq_even;
-            acc += x_odd * w_deq_odd;
-        }
+        int w_row_base = k_base >> 1;
+
+        unsigned char wp0 = w_q[w_row_base * N + n];
+        unsigned char w0_e = wp0 & 0xF;
+        unsigned char w0_o = (wp0 >> 4) & 0xF;
+        float x0_e = __bfloat162float(x_row[k_base]);
+        float x0_o = __bfloat162float(x_row[k_base + 1]);
+        acc += x0_e * (((float)w0_e - zero) * scale);
+        acc += x0_o * (((float)w0_o - zero) * scale);
+
+        unsigned char wp1 = w_q[(w_row_base + 1) * N + n];
+        unsigned char w1_e = wp1 & 0xF;
+        unsigned char w1_o = (wp1 >> 4) & 0xF;
+        float x1_e = __bfloat162float(x_row[k_base + 2]);
+        float x1_o = __bfloat162float(x_row[k_base + 3]);
+        acc += x1_e * (((float)w1_e - zero) * scale);
+        acc += x1_o * (((float)w1_o - zero) * scale);
+
+        unsigned char wp2 = w_q[(w_row_base + 2) * N + n];
+        unsigned char w2_e = wp2 & 0xF;
+        unsigned char w2_o = (wp2 >> 4) & 0xF;
+        float x2_e = __bfloat162float(x_row[k_base + 4]);
+        float x2_o = __bfloat162float(x_row[k_base + 5]);
+        acc += x2_e * (((float)w2_e - zero) * scale);
+        acc += x2_o * (((float)w2_o - zero) * scale);
+
+        unsigned char wp3 = w_q[(w_row_base + 3) * N + n];
+        unsigned char w3_e = wp3 & 0xF;
+        unsigned char w3_o = (wp3 >> 4) & 0xF;
+        float x3_e = __bfloat162float(x_row[k_base + 6]);
+        float x3_o = __bfloat162float(x_row[k_base + 7]);
+        acc += x3_e * (((float)w3_e - zero) * scale);
+        acc += x3_o * (((float)w3_o - zero) * scale);
+
+        unsigned char wp4 = w_q[(w_row_base + 4) * N + n];
+        unsigned char w4_e = wp4 & 0xF;
+        unsigned char w4_o = (wp4 >> 4) & 0xF;
+        float x4_e = __bfloat162float(x_row[k_base + 8]);
+        float x4_o = __bfloat162float(x_row[k_base + 9]);
+        acc += x4_e * (((float)w4_e - zero) * scale);
+        acc += x4_o * (((float)w4_o - zero) * scale);
+
+        unsigned char wp5 = w_q[(w_row_base + 5) * N + n];
+        unsigned char w5_e = wp5 & 0xF;
+        unsigned char w5_o = (wp5 >> 4) & 0xF;
+        float x5_e = __bfloat162float(x_row[k_base + 10]);
+        float x5_o = __bfloat162float(x_row[k_base + 11]);
+        acc += x5_e * (((float)w5_e - zero) * scale);
+        acc += x5_o * (((float)w5_o - zero) * scale);
+
+        unsigned char wp6 = w_q[(w_row_base + 6) * N + n];
+        unsigned char w6_e = wp6 & 0xF;
+        unsigned char w6_o = (wp6 >> 4) & 0xF;
+        float x6_e = __bfloat162float(x_row[k_base + 12]);
+        float x6_o = __bfloat162float(x_row[k_base + 13]);
+        acc += x6_e * (((float)w6_e - zero) * scale);
+        acc += x6_o * (((float)w6_o - zero) * scale);
+
+        unsigned char wp7 = w_q[(w_row_base + 7) * N + n];
+        unsigned char w7_e = wp7 & 0xF;
+        unsigned char w7_o = (wp7 >> 4) & 0xF;
+        float x7_e = __bfloat162float(x_row[k_base + 14]);
+        float x7_o = __bfloat162float(x_row[k_base + 15]);
+        acc += x7_e * (((float)w7_e - zero) * scale);
+        acc += x7_o * (((float)w7_o - zero) * scale);
+
+        unsigned char wp8 = w_q[(w_row_base + 8) * N + n];
+        unsigned char w8_e = wp8 & 0xF;
+        unsigned char w8_o = (wp8 >> 4) & 0xF;
+        float x8_e = __bfloat162float(x_row[k_base + 16]);
+        float x8_o = __bfloat162float(x_row[k_base + 17]);
+        acc += x8_e * (((float)w8_e - zero) * scale);
+        acc += x8_o * (((float)w8_o - zero) * scale);
+
+        unsigned char wp9 = w_q[(w_row_base + 9) * N + n];
+        unsigned char w9_e = wp9 & 0xF;
+        unsigned char w9_o = (wp9 >> 4) & 0xF;
+        float x9_e = __bfloat162float(x_row[k_base + 18]);
+        float x9_o = __bfloat162float(x_row[k_base + 19]);
+        acc += x9_e * (((float)w9_e - zero) * scale);
+        acc += x9_o * (((float)w9_o - zero) * scale);
+
+        unsigned char wp10 = w_q[(w_row_base + 10) * N + n];
+        unsigned char w10_e = wp10 & 0xF;
+        unsigned char w10_o = (wp10 >> 4) & 0xF;
+        float x10_e = __bfloat162float(x_row[k_base + 20]);
+        float x10_o = __bfloat162float(x_row[k_base + 21]);
+        acc += x10_e * (((float)w10_e - zero) * scale);
+        acc += x10_o * (((float)w10_o - zero) * scale);
+
+        unsigned char wp11 = w_q[(w_row_base + 11) * N + n];
+        unsigned char w11_e = wp11 & 0xF;
+        unsigned char w11_o = (wp11 >> 4) & 0xF;
+        float x11_e = __bfloat162float(x_row[k_base + 22]);
+        float x11_o = __bfloat162float(x_row[k_base + 23]);
+        acc += x11_e * (((float)w11_e - zero) * scale);
+        acc += x11_o * (((float)w11_o - zero) * scale);
+
+        unsigned char wp12 = w_q[(w_row_base + 12) * N + n];
+        unsigned char w12_e = wp12 & 0xF;
+        unsigned char w12_o = (wp12 >> 4) & 0xF;
+        float x12_e = __bfloat162float(x_row[k_base + 24]);
+        float x12_o = __bf

... (20271 more chars)
args
{
  "content": "<29194 chars \u2014 see diff>",
  "filePath": "/home/infatoshi/cuda/KernelBench-Hard/problems/07_w4a16_gemm/solution.py"
}
tool
stdout (24 chars)
Wrote file successfully.
assistant
in 797out 9939cache_r 130976cache_w 0
assistant
bash
args
{
  "command": "python check.py 2>&1",
  "description": "Run check.py",
  "timeout": 180000
}
tool
stdout (5 chars)
PASS
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in 10070out 51cache_r 131744cache_w 0
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bash
args
{
  "command": "python benchmark.py 2>&1",
  "description": "Run benchmark",
  "timeout": 300000
}
tool
stdout (1918 chars) — TRUNCATED
/home/infatoshi/.local/lib/python3.12/site-packages/bitsandbytes/backends/cuda/ops.py:468: FutureWarning: _check_is_size will be removed in a future PyTorch release along with guard_size_oblivious.     Use _check(i >= 0) instead.
  torch._check_is_size(blocksize)
/home/infatoshi/.local/lib/python3.12/site-packages/bitsandbytes/backends/cuda/ops.py:468: FutureWarning: _check_is_size will be removed in a future PyTorch release along with guard_size_oblivious.     Use _check(i >= 0) instead.
  torch._check_is_size(blocksize)
shape=0 variant=eager tflops=0.131 gbps=34.971 ms=0.766
shape=0 variant=compiled tflops=0.669 gbps=178.040 ms=0.150
shape=0 variant=sota tflops=2.292 gbps=609.550 ms=0.044
shape=0 variant=solution tflops=0.511 gbps=135.780 ms=0.197
shape=0 solution_peak_fraction=0.0754
shape=1 variant=eager tflops=4.199 gbps=36.225 ms=0.767
shape=1 variant=compiled tflops=20.565 gbps=177.396 ms=0.157
shape=1 variant=sota tflops=23.424 gbps=202.060 ms=0.138
shape=1 variant=solution tflops=7.463 gbps=64.380 ms=0.432
shape=1 solution_peak_fraction=0.0358
shape=2 variant=eager tflops=31.427 gbps=42.839 ms=0.820
shape=2 variant=compiled tflops=119.998 gbps=163.571 ms=0.215
shape=2 variant=sota tflops=134.307 gbps=183.077 ms=0.192
shape=2 variant=solution tflops=8.242 gbps=11.235 ms=3.127
shape=2 solution_peak_fraction=0.0062
shape=3 variant=eager tflops=0.183 gbps=48.668 ms=0.183
shape=3 variant=compiled tflops=0.501 gbps=133.416 ms=0.067
shape=3 variant=sota tflops=1.251 gbps=33

... (418 more chars)
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todowrite
args
{
  "todos": [
    {
      "content": "Research PTX/CUTLASS W4A16 patterns for SM120",
      "priority": "high",
      "status": "completed"
    },
    {
      "content": "Write fused W4A16 GEMM kernel (solution.py)",
      "priority": "high",
      "status": "completed"
    },
    {
      "content": "Run check.py correctness tests",
      "priority": "high",
      "status": "completed"
    },
    {
      "content": "Profile with benchmark.py and optimize",
      "priority": "high",
      "status": "completed"
    },
    {
      "content": "Iterate until PASS with good performance",
      "pri

... (55 more chars)
tool
stdout (440 chars)
content: 'Research PTX/CUTLASS W4A16 patterns for SM120'
status: 'completed'
priority: 'high'
content: 'Write fused W4A16 GEMM kernel (solution.py)'
status: 'completed'
priority: 'high'
content: 'Run check.py correctness tests'
status: 'completed'
priority: 'high'
content: 'Profile with benchmark.py and optimize'
status: 'completed'
priority: 'high'
content: 'Iterate until PASS with good performance'
status: 'completed'
priority: 'high'
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PASS. The solution passes all correctness tests with atol/rtol=0.1. **What was built:** A CUDA C++ kernel via `torch.utils.cpp_extension.load_inline` that fuses int4 unpacking and GEMM in a single pass. The key optimization is unrolling all 64 K-iterations per group to maximize instruction-level parallelism on the CUDA cores, since the bottleneck is memory-bandwidth on the int4 weight stream. **Performance summary (peak_fraction=0.0305, RESULT=LOW):** - Decode M=1: 0.51 TFLOPS (vs SOTA 2.3 TFLOPS, bitsandbytes NF4) - Small prefill M=32: 7.5 TFLOPS (vs SOTA 23.4 TFLOPS) - Large prefill M=256: 8.2 TFLOPS (vs SOTA 134 TFLOPS — compute-bound regime) The gap to SOTA is expected since bitsandbytes NF4 uses different quantization schemes and has highly optimized Blackwell kernels. The current kernel processes everything on CUDA cores with scalar loads, which tops out at ~135 GB/s bandwidth utilization. Achieving SOTA-level performance would require CUTLASS mixed-input GEMM with tensor core accumulation (W4A16 accumulation in INT8/INT4, output in BF16) or hardware-specific kernels like Marlin (no SM120 support yet).
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