codex / ? session: ? cwd: /workspace/problems/01_fp8_gemm
harness
codex
model
?
turns
143
tools called
94
events
243
input toks
8,442,868
output toks
53,752
cache hit
8,160,384
solution.py
final answer
benchmark.log
check.log
result.json
import torch
import torch.nn as nn
import triton
import triton.language as tl


E4M3_MAX = 448.0


@triton.jit
def _fp8_gemm_kernel(
    x_ptr,
    w_ptr,
    scale_ptr,
    y_ptr,
    M: tl.constexpr,
    N: tl.constexpr,
    K: tl.constexpr,
    BLOCK_M: tl.constexpr,
    BLOCK_N: tl.constexpr,
    BLOCK_K: tl.constexpr,
    GROUP_M: tl.constexpr,
):
    pid = tl.program_id(0)
    num_pid_m = tl.cdiv(M, BLOCK_M)
    num_pid_n = tl.cdiv(N, BLOCK_N)
    group_size = GROUP_M * num_pid_n
    group_id = pid // group_size
    first_pid_m = group_id * GROUP_M
    group_m = tl.minimum(num_pid_m - first_pid_m, GROUP_M)
    pid_in_group = pid - group_id * group_size
    pid_m = first_pid_m + (pid_in_group % group_m)
    pid_n = pid_in_group // group_m

    offs_m = pid_m * BLOCK_M + tl.arange(0, BLOCK_M)
    offs_n = pid_n * BLOCK_N + tl.arange(0, BLOCK_N)
    offs_k = tl.arange(0, BLOCK_K)

    acc = tl.zeros((BLOCK_M, BLOCK_N), tl.float32)
    full_k = (K // BLOCK_K) * BLOCK_K
    for k0 in range(0, full_k, BLOCK_K):
        k = k0 + offs_k
        a = tl.load(x_ptr + offs_m[:, None] * K + k[None, :])
        b = tl.load(w_ptr + offs_n[None, :] * K + k[:, None])
        acc = tl.dot(a, b, acc, out_dtype=tl.float32)

    if full_k < K:
        k = full_k + offs_k
        a = tl.load(
            x_ptr + offs_m[:, None] * K + k[None, :],
            mask=k[None, :] < K,
            other=0.0,
        )
        b = tl.load(
            w_ptr + offs_n[None, :] * K + k[:, None],
            mask=k[:, None] < K,
            other=0.0,
        )
        acc = tl.dot(a, b, acc, out_dtype=tl.float32)

    scales = tl.load(scale_ptr + offs_n, mask=offs_n < N, other=0.0)
    acc = acc * scales[None, :]
    tl.store(
        y_ptr + offs_m[:, None] * N + offs_n[None, :],
        acc,
        mask=(offs_m[:, None] < M) & (offs_n[None, :] < N),
    )


def _launch_fp8_gemm(x: torch.Tensor, weight: torch.Tensor, weight_scale: torch.Tensor, M: int, N: int, K: int):
    y = torch.empty((M, N), device=x.device, dtype=torch.bfloat16)

    if M <= 64:
        bm, bn, bk = 32, 32, 256
        warps, stages, group_m = 4, 4, 1
    elif K == 4224 and M == 4096 and N == 4096:
        bm, bn, bk = 256, 128, 128
        warps, stages, group_m = 8, 3, 4
    elif K % 128 != 0:
        bm, bn, bk = 128, 128, 128
        warps, stages, group_m = 4, 3, 8
    elif N >= 8192:
        bm, bn, bk = 128, 256, 64
        warps, stages, group_m = 8, 4, 2
    else:
        bm, bn, bk = 256, 128, 64
        warps, stages, group_m = 8, 4, 4

    grid = (triton.cdiv(M, bm) * triton.cdiv(N, bn),)
    _fp8_gemm_kernel[grid](
        x,
        weight,
        weight_scale,
        y,
        M,
        N,
        K,
        BLOCK_M=bm,
        BLOCK_N=bn,
        BLOCK_K=bk,
        GROUP_M=group_m,
        num_warps=warps,
        num_stages=stages,
    )
    return y


class Model(nn.Module):
    def __init__(self, M: int, N: int, K: int):
        super().__init__()
        self.M, self.N, self.K = M, N, K
        self._weight_pad = None
        self._weight_pad_key = None
        self._x_pad = None
        w = torch.empty(N, K, dtype=torch.bfloat16)
        nn.init.normal_(w, std=0.02)
        s = (w.float().abs().amax(dim=1, keepdim=True) / E4M3_MAX).clamp(min=1e-12)
        w_fp8 = (w.float() / s).to(torch.float8_e4m3fn)
        self.register_buffer("weight", w_fp8)
        self.register_buffer("weight_scale", s.squeeze(1).to(torch.float32))

    def forward(self, x: torch.Tensor) -> torch.Tensor:
        if not x.is_cuda:
            x_bf = x.to(torch.bfloat16)
            w_bf = self.weight.to(torch.bfloat16)
            y = (x_bf @ w_bf.T).float()
            y = y * self.weight_scale[None, :]
            return y.to(torch.bfloat16)
        if self.K % 128 != 0:
            k_pad = ((self.K + 127) // 128) * 128
            w_key = (self.weight.data_ptr(), self.weight._version, self.weight.device, self.weight.shape)
            if self._weight_pad is None or self._weight_pad_key != w_key:
                weight_pad = torch.empty((self.N, k_pad), device=x.device, dtype=self.weight.dtype)
                weight_pad[:, : self.K].copy_(self.weight)
                weight_pad[:, self.K :].zero_()
                self._weight_pad = weight_pad
                self._weight_pad_key = w_key
            if (
                self._x_pad is None
                or self._x_pad.device != x.device
                or self._x_pad.shape != (self.M, k_pad)
            ):
                self._x_pad = torch.empty((self.M, k_pad), device=x.device, dtype=x.dtype)
            self._x_pad[:, : self.K].copy_(x)
            self._x_pad[:, self.K :].zero_()
            return _launch_fp8_gemm(self._x_pad, self._weight_pad, self.weight_scale, self.M, self.N, k_pad)
        return _launch_fp8_gemm(x, self.weight, self.weight_scale, self.M, self.N, self.K)


M = 4096
N = 4096
K = 4096


def get_inputs():
    x = (torch.rand(M, K) * 8 - 4).to(torch.float8_e4m3fn)
    return [x]


def get_init_inputs():
    return [M, N, K]
Implemented the FP8 GEMM in [solution.py](/workspace/problems/01_fp8_gemm/solution.py). What changed: - Added a Triton `tl.dot` FP8 x FP8 tensor-core kernel with fp32 accumulation and fused per-channel `weight_scale`. - Tuned separate tile configs for square, odd-K, skinny-M, and wide-N shapes. - Added a dedicated odd-K path that pads K=4127 to 4224, caches the padded weight, pads activation each forward, then runs the faster aligned FP8 kernel. - Preserved the required `Model`, `get_inputs`, and `get_init_inputs` interfaces and registered `weight` / `weight_scale`. Verification: - `uv run python check.py` -> `PASS` - `uv run python benchmark.py` -> `RESULT: OK`, `peak_fraction: 0.3640` Latest benchmark: - shape 0: `621.558 TFLOP/s`, `0.221 ms` - shape 1: `565.683 TFLOP/s`, `0.245 ms` - shape 2: `73.484 TFLOP/s`, `0.058 ms` - shape 3: `679.307 TFLOP/s`, `0.708 ms`
warning: `VIRTUAL_ENV=/home/infatoshi/kernelbench.com/benchmarks/hard/.venv` does not match the project environment path `/home/infatoshi/kernelbench.com/benchmarks/hard/outputs/runs/20260614_144224_codex_gpt-5.5_01_fp8_gemm/repo/.venv` and will be ignored; use `--active` to target the active environment instead
benchmark_event event=variant_start shape=0 variant=solution ts=2026-06-14T20:55:24.597452+00:00
benchmark_event event=variant_end shape=0 variant=solution ts=2026-06-14T20:55:24.804977+00:00 elapsed_s=0.208 ms=0.220288
shape=0 variant=solution tflops=623.906 gbps=304.641 ms=0.220
shape=0 solution_peak_fraction=0.6239
benchmark_event event=variant_start shape=1 variant=solution ts=2026-06-14T20:55:25.320439+00:00
benchmark_event event=variant_end shape=1 variant=solution ts=2026-06-14T20:55:25.337194+00:00 elapsed_s=0.017 ms=0.245248
shape=1 variant=solution tflops=564.649 gbps=274.672 ms=0.245
shape=1 solution_peak_fraction=0.5646
benchmark_event event=variant_start shape=2 variant=solution ts=2026-06-14T20:55:27.180146+00:00
benchmark_event event=variant_end shape=2 variant=solution ts=2026-06-14T20:55:27.185669+00:00 elapsed_s=0.006 ms=0.058656
shape=2 variant=solution tflops=73.223 gbps=1157.517 ms=0.059
shape=2 solution_peak_fraction=0.0732
benchmark_event event=variant_start shape=3 variant=solution ts=2026-06-14T20:55:28.854816+00:00
benchmark_event event=variant_end shape=3 variant=solution ts=2026-06-14T20:55:28.886718+00:00 elapsed_s=0.032 ms=0.708496
shape=3 variant=solution tflops=678.954 gbps=272.320 ms=0.708
shape=3 solution_peak_fraction=0.6790
peak_fraction: 0.3638
RESULT: OK
warning: `VIRTUAL_ENV=/home/infatoshi/kernelbench.com/benchmarks/hard/.venv` does not match the project environment path `/home/infatoshi/kernelbench.com/benchmarks/hard/outputs/runs/20260614_144224_codex_gpt-5.5_01_fp8_gemm/repo/.venv` and will be ignored; use `--active` to target the active environment instead
warning: Ignoring existing virtual environment linked to non-existent Python interpreter: /home/infatoshi/kernelbench.com/benchmarks/hard/outputs/runs/20260614_144224_codex_gpt-5.5_01_fp8_gemm/repo/.venv/bin/python3 -> python
Using CPython 3.11.15
Removed virtual environment at: /home/infatoshi/kernelbench.com/benchmarks/hard/outputs/runs/20260614_144224_codex_gpt-5.5_01_fp8_gemm/repo/.venv
Creating virtual environment at: /home/infatoshi/kernelbench.com/benchmarks/hard/outputs/runs/20260614_144224_codex_gpt-5.5_01_fp8_gemm/repo/.venv
   Building kernelbench-hard @ file:///home/infatoshi/kernelbench.com/benchmarks/hard/outputs/runs/20260614_144224_codex_gpt-5.5_01_fp8_gemm/repo
      Built kernelbench-hard @ file:///home/infatoshi/kernelbench.com/benchmarks/hard/outputs/runs/20260614_144224_codex_gpt-5.5_01_fp8_gemm/repo
Installed 56 packages in 112ms
PASS
{
    "run_id": "20260614_144224_codex_gpt-5.5_01_fp8_gemm",
    "run_group": "",
    "problem": "01_fp8_gemm",
    "harness": "codex",
    "model": "gpt-5.5",
    "reasoning_effort": "xhigh",
    "started_at": "2026-06-14T14:42:24-06:00",
    "harness_finished_at": "2026-06-14T14:55:15-06:00",
    "finished_at": "2026-06-14T14:55:29-06:00",
    "start_epoch": 1781469744,
    "harness_end_epoch": 1781470515,
    "end_epoch": 1781470529,
    "has_solution": true,
    "correct": true,
    "failure_reason": "pass",
    "retryable_infra_failure": false,
    "minimum_useful_output_tokens": 5000,
    "peak_fraction": 0.3638,
    "template_mutated": false,
    "elapsed_seconds": 771,
    "total_elapsed_seconds": 785,
    "check_elapsed_seconds": 8,
    "benchmark_elapsed_seconds": 6,
    "check_timeout_seconds": 180,
    "benchmark_timeout_seconds": 1800,
    "check_exit_code": 0,
    "benchmark_exit_code": 0,
    "harness_exit_code": 0,
    "session_complete": true,
    "agent_cuda_disabled": false,
    "agent_container": true,
    "agent_container_image": "nvcr.io/nvidia/tensorrt-llm/release:latest",
    "agent_container_network": "bridge",
    "gpu_queue_mode": "agent_container_native_profiling_path_wrapper_gpu_lock",
    "output_tokens_per_second": 69.71725032425421,
    "usage": {"input_tokens": 8442868, "output_tokens": 53752, "cache_read_tokens": 8160384, "cache_creation_tokens": null, "reasoning_tokens": 21495, "total_cost_usd": null}
}

timeline (243 events)

system
session start model=None ctx=?
system
task_started turn=019ec7df
system
<permissions instructions> Filesystem sandboxing defines which files can be read or written. `sandbox_mode` is `danger-full-access`: No filesystem sandboxing - all commands are permitted. Network access is enabled. Approval policy is currently never. Do not provide the `sandbox_permissions` for any reason, commands will be rejected. </permissions instructions> <apps_instructions> ## Apps (Connectors) Apps (Connectors) can be explicitly triggered in user messages in the format `[$app-name](app://{connector_id})`. Apps can also be implicitly triggered as long as the context suggests usage of available apps. An app is equivalent to a set of MCP tools within the `codex_apps` MCP. An installed app's MCP tools are either provided to you already, or can be lazy-loaded through the `tool_search` tool. If `tool_search` is available, the apps that are searchable by `tools_search` will be listed by it. Do not additionally call list_mcp_resources or list_mcp_resource_templates for apps. </apps_instructions> <skills_instructions> ## Skills A skill is a set of local instructions to follow that is stored in a `SKILL.md` file. Below is the list of skills that can be used. Each entry includes a name, description, and file path so you can open the source for full instructions when using a specific skill. ### Available skills - imagegen: Generate or edit raster images when the task benefits from AI-created bitmap visuals such as photos, illustrations, textures, sprites, mockups, or transparent-background cutouts. Use when Codex should create a brand-new image, transform an existing image, or derive visual variants from references, and the output should be a bitmap asset rather than repo-native code or vector. Do not use when the task is better handled by editing existing SVG/vector/code-native assets, extending an established icon or logo system, or building the visual directly in HTML/CSS/canvas. (file: /home/agent/.codex/skills/.system/imagegen/SKILL.md) - openai-docs: Use when the user asks how to build with OpenAI products or APIs and needs up-to-date official documentation with citations, help choosing the latest model for a use case, or model upgrade and prompt-upgrade guidance; prioritize OpenAI docs MCP tools, use bundled references only as helper context, and restrict any fallback browsing to official OpenAI domains. (file: /home/agent/.codex/skills/.system/openai-docs/SKILL.md) - plugin-creator: Create and scaffold plugin directories for Codex with a required `.codex-plugin/plugin.json`, optional plugin folders/files, and baseline placeholders you can edit before publishing or testing. Use when Codex needs to create a new local plugin, add optional plugin structure, or generate or update repo-root `.agents/plugins/marketplace.json` entries for plugin ordering and availability metadata. (file: /home/agent/.codex/skills/.system/plugin-creator/SKILL.md) - skill-creator: Guide for creating effective skills. This skill should be used when users want to create a new skill (or update an existing skill) that extends Codex's capabilities with specialized knowledge, workflows, or tool integrations. (file: /home/agent/.codex/skills/.system/skill-creator/SKILL.md) - skill-installer: Install Codex skills into $CODEX_HOME/skills from a curated list or a GitHub repo path. Use when a user asks to list installable skills, install a curated skill, or install a skill from another repo (including private repos). (file: /home/agent/.codex/skills/.system/skill-installer/SKILL.md) ### How to use skills - Discovery: The list above is the skills available in this session (name + description + file path). Skill bodies live on disk at the listed paths. - Trigger rules: If the user names a skill (with `$SkillName` or plain text) OR the task clearly matches a skill's description shown above, you must use that skill for that turn. Multiple mentions mean use them all. Do not carry skills across turns unless re-mentioned. - Missing/blocked: If a named skill isn't in the list or the path can't be read, say so briefly and continue with the best fallback. - How to use a skill (progressive disclosure): 1) After deciding to use a skill, open its `SKILL.md`. Read only enough to follow the workflow. 2) When `SKILL.md` references relative paths (e.g., `scripts/foo.py`), resolve them relative to the skill directory listed above first, and only consider other paths if needed. 3) If `SKILL.md` points to extra folders such as `references/`, load only the specific files needed for the request; don't bulk-load everything. 4) If `scripts/` exist, prefer running or patching them instead of retyping large code blocks. 5) If `assets/` or templates exist, reuse them instead of recreating from scratch. - Coordination and sequencing: - If multiple skills apply, choose the minimal set that covers the request and state the order you'll use them. - Announce which skill(s) you're using and why (one short line). If you skip an obvious skill, say why. - Context hygiene: - Keep context small: summarize long sections instead of pasting them; only load extra files when needed. - Avoid deep reference-chasing: prefer opening only files directly linked from `SKILL.md` unless you're blocked. - When variants exist (frameworks, providers, domains), pick only the relevant reference file(s) and note that choice. - Safety and fallback: If a skill can't be applied cleanly (missing files, unclear instructions), state the issue, pick the next-best approach, and continue. </skills_instructions>
user
<environment_context> <cwd>/workspace/problems/01_fp8_gemm</cwd> <shell>bash</shell> <current_date>2026-06-14</current_date> <timezone>Etc/UTC</timezone> </environment_context>
user
I need you to optimize an FP8 GEMM for the RTX PRO 6000 (SM120 Blackwell, GDDR7, 1.8 TB/s). The reference implementation is in reference.py and your kernel goes in solution.py. You can make whatever mess you want in this directory — scratch files, intermediate kernels, build artifacts, profiling traces — but the final answer has to be in solution.py with the same Model, get_inputs, and get_init_inputs interface as reference.py. This is a genuine fp8 x fp8 GEMM. Both operands are fp8_e4m3. The activation x is fp8_e4m3 (M, K). The weight is given to you ALREADY quantized: the Model holds `weight` as fp8_e4m3 (N, K) normalized into the e4m3 range, plus `weight_scale` (N,), a per-output-channel dequant scale. You return y = (x @ weight.T) * weight_scale as bf16 (M, N). Read reference.py — it defines this exactly; your Model must register the same `weight` and `weight_scale` buffers so the graded state_dict loads. To actually score well you must run a real fp8 x fp8 tensor-core MMA (fp8 inputs, fp32 accumulate) and apply the per-channel scale. Upcasting both operands to bf16 and doing a bf16 GEMM is correct but it caps at roughly HALF the roofline — the roofline here is the fp8 peak (~1000 TFLOPS) and bf16 tensor cores run at ~half that. So a bf16 fallback passes correctness but leaves ~2x on the table; the fp8 path is the point. Correctness tolerance on the bf16 output is ~0.2 abs/rel (fp8 has real accumulation noise, so the bar is loose), but it has to match the reference within that across every shape and the numeric-stress cases. The shapes you must handle are M=4096 N=4096 K=4096 (square aligned, the easy case), M=4096 N=4096 K=4127 (K not a multiple of 128, which forces predicated tails on tile-quantized kernels), M=32 N=8192 K=8192 (skinny M, decode-style, memory-bound), and M=4096 N=14336 K=4096 (Llama-3 up-proj). This needs to be a real custom kernel. Don't reach for torch._scaled_mm or torch.ops.aten._scaled_mm — they're off-limits and using them fails correctness. Triton tl.dot on fp8, CUDA C++ via torch.utils.cpp_extension.load_inline, inline PTX (mma.sync ... e4m3), or CUTLASS all work — whatever fits. Anything you're uncertain about, look up PTX docs, clone CUTLASS or other reference repos, read library headers, and investigate. Your flywheel is implement, profile (ncu, nsys, torch.profiler — whatever's useful) and time it with benchmark.py, verify correctness by running `python check.py` and reading the output, then iterate. Don't substitute your own one-off correctness snippets for check.py — it iterates over every shape, your spot-check almost certainly won't. If `python check.py` hasn't printed PASS, you're not done. Take as long as you need to actually push the number up. Workspace isolation note: you are already running inside the archive-local problem workspace, /workspace/problems/01_fp8_gemm. Write the final answer to solution.py in the current directory only. The source repository's problems/ tree is not mounted. Container note: inside this run, the visible workspace path is /workspace/problems/01_fp8_gemm. The source repository, old runs, leaderboards, and host harness memory are not mounted. Container network mode is bridge. Run all Python through `uv run ...` so you use the workspace uv environment; it is built from the same uv.lock as the official scoring environment. The container image's system python has a different torch build and is NOT the scoring environment.
assistant
I’ll inspect the harness and current implementation first so the kernel matches the expected interfaces and the benchmark path. Then I’ll iterate through `uv run python check.py` and `uv run python benchmark.py` rather than relying on ad hoc tests.
assistant
exec_command
args
{
  "cmd": "pwd && rg --files",
  "workdir": "/workspace/problems/01_fp8_gemm",
  "yield_time_ms": 1000,
  "max_output_tokens": 12000
}
assistant
exec_command
args
{
  "cmd": "sed -n '1,220p' reference.py",
  "workdir": "/workspace/problems/01_fp8_gemm",
  "yield_time_ms": 1000,
  "max_output_tokens": 12000
}
assistant
exec_command
args
{
  "cmd": "sed -n '1,260p' check.py",
  "workdir": "/workspace/problems/01_fp8_gemm",
  "yield_time_ms": 1000,
  "max_output_tokens": 16000
}
assistant
exec_command
args
{
  "cmd": "sed -n '1,260p' benchmark.py",
  "workdir": "/workspace/problems/01_fp8_gemm",
  "yield_time_ms": 1000,
  "max_output_tokens": 16000
}
assistant
exec_command
args
{
  "cmd": "sed -n '1,220p' solution.py 2>/dev/null || true",
  "workdir": "/workspace/problems/01_fp8_gemm",
  "yield_time_ms": 1000,
  "max_output_tokens": 12000
}
tool
stdout (212 chars)
Chunk ID: 324f6f
Wall time: 0.0000 seconds
Process exited with code 0
Original token count: 28
Output:
/workspace/problems/01_fp8_gemm
PROMPT.txt
shapes.py
sota.py
reference.py
check.py
benchmark.py
problem.yaml
tool
stdout (2054 chars) — TRUNCATED
Chunk ID: 5f5934
Wall time: 0.0000 seconds
Process exited with code 0
Original token count: 488
Output:
"""FP8 e4m3 GEMM reference (correctness only, NOT the SOTA baseline).

Genuine fp8 x fp8: BOTH operands are fp8_e4m3. The weight is stored as fp8
(normalized into the e4m3 range) together with a per-output-channel scale, the
standard scaled-fp8 inference layout. The reference upcasts the fp8 operands to
bf16 and matmuls, then applies the per-channel scale — this DEFINES the fp8
target. A real fp8 x fp8 MMA kernel matches it (and can exceed the bf16 roofline
ceiling of ~0.5); a bf16-upcast kernel also matches but stays capped at ~0.5.
"""
import torch
import torch.nn as nn

OP_TYPE = "gemm"
SUPPORTED_PRECISIONS = ["fp8_e4m3"]
HARDWARE_REQUIRED = ["RTX_PRO_6000", "H100", "B200"]
E4M3_MAX = 448.0


class Model(nn.Module):
    """y = ((x @ w.T) * weight_scale).to(bf16).

    x: fp8_e4m3 (M, K).  w: fp8_e4m3 (N, K) normalized to the e4m3 range.
    weight_scale: (N,) per-output-channel dequant scale.
    """

    def __init__(self, M: int, N: int, K: int):
        super().__init__()
        self.M, self.N, self.K = M, N, K
        w = torch.empty(N, K, dtype=torch.bfloat16)
        nn.init.normal_(w, std=0.02)
        s = (w.float().abs().amax(dim=1, keepdim=True) / E4M3_MAX).clamp(min=1e-12)  # (N,1)
        w_fp8 = (w.float() / s).to(torch.float8_e4m3fn)
        self.register_buffer("weight", w_fp8)                         # (N, K) fp8
        self.register_buffer("weight_scal

... (554 more chars)
tool
stdout (4308 chars) — TRUNCATED
Chunk ID: 42fa42
Wall time: 0.0000 seconds
Process exited with code 0
Original token count: 1052
Output:
"""Correctness runner for FP8 GEMM.

Runs solution.Model vs reference.Model across all shapes in shapes.py, 3 seeds
each, with per-dtype atol/rtol. Also rejects forbidden ops by grep.
"""
import re
import sys
from pathlib import Path

import torch
import yaml

# Make the repo's src/ importable
REPO_ROOT = Path(__file__).resolve().parents[2]
sys.path.insert(0, str(REPO_ROOT))

from src.eval.correctness import check_correctness  # noqa: E402
from src.eval.numeric_stress import (  # noqa: E402
    numeric_stress_cases,
    numeric_stress_context,
    tolerance_for_case,
)


def main():
    try:
        import reference
        import shapes
        import solution
    except Exception as e:
        print(f"FAIL: import error: {e}")
        sys.exit(1)

    problem_yaml = Path("problem.yaml")
    meta = yaml.safe_load(problem_yaml.read_text()) if problem_yaml.exists() else {}

    # --- Forbidden-op check ------------------------------------------------
    sol_src = Path("solution.py").read_text() if Path("solution.py").exists() else ""
    for forbidden in meta.get("forbidden", []):
        pat = re.escape(forbidden)
        if re.search(pat, sol_src):
            print(f"FAIL: forbidden op used: {forbidden}")
            sys.exit(1)

    device = torch.device("cuda:0")
    tol_override = meta.get("tolerance") or None

    # --- Per-shape correctness ------------------------

... (2808 more chars)
tool
stdout (5252 chars) — TRUNCATED
Chunk ID: 4a47a4
Wall time: 0.0000 seconds
Process exited with code 0
Original token count: 1287
Output:
"""Roofline benchmark for FP8 GEMM.

For each shape: times the agent's solution first. Optional eager, compiled,
and SOTA diagnostics are enabled with KBH_BENCHMARK_BASELINES=1. Reports achieved TFLOPS, GB/s, and peak_fraction.

Output lines the harness picks up:
  shape=<idx> variant=<name> tflops=<N> gbps=<N> ms=<N>
  peak_fraction: <N>  (geomean over shapes of solution's peak_fraction)
"""
import sys
from math import exp, log
from pathlib import Path

import torch
import yaml

REPO_ROOT = Path(__file__).resolve().parents[2]
sys.path.insert(0, str(REPO_ROOT))

from src.eval.roofline import compute_gbps, compute_tflops, peak_fraction  # noqa: E402
from src.eval.timing import benchmark_baselines_enabled, time_variant  # noqa: E402
from src.hardware import get as get_hw  # noqa: E402


def _eval_formula(expr: str, vars: dict) -> float:
    # Very small eval: only names from `vars` are valid.
    return float(eval(expr, {"__builtins__": {}}, vars))


def main():
    import reference
    import shapes
    import solution

    meta = yaml.safe_load(Path("problem.yaml").read_text())
    hw = get_hw(meta["hardware"][0])
    peak_tflops = hw.peak_tflops_dense.get(meta["peak_tflops_key"], 0.0)
    peak_gbps = hw.peak_bandwidth_gb_s
    regime = meta.get("regime", "compute")
    flops_formula = meta["flops_formula"]
    bytes_formula = meta["bytes_formula"]
    num_perf_trials = in

... (3752 more chars)
tool
stdout (102 chars)
Chunk ID: 9994dc
Wall time: 0.0000 seconds
Process exited with code 0
Original token count: 0
Output:
assistant
The harness is strict about loading `weight` and `weight_scale`, and it rejects `_scaled_mm` by source grep. I’m checking the shape metadata and any included baseline next so I can avoid fighting the scoring setup.
assistant
exec_command
args
{
  "cmd": "sed -n '1,200p' shapes.py",
  "workdir": "/workspace/problems/01_fp8_gemm",
  "yield_time_ms": 1000,
  "max_output_tokens": 8000
}
assistant
exec_command
args
{
  "cmd": "sed -n '1,220p' problem.yaml",
  "workdir": "/workspace/problems/01_fp8_gemm",
  "yield_time_ms": 1000,
  "max_output_tokens": 8000
}
assistant
exec_command
args
{
  "cmd": "sed -n '1,260p' sota.py",
  "workdir": "/workspace/problems/01_fp8_gemm",
  "yield_time_ms": 1000,
  "max_output_tokens": 12000
}
assistant
exec_command
args
{
  "cmd": "<245 chars \u2014 see below>",
  "workdir": "/workspace/problems/01_fp8_gemm",
  "yield_time_ms": 1000,
  "max_output_tokens": 12000
}
cmd (245 chars)
uv run python - <<'PY'
import torch, sys
print(torch.__version__)
print(torch.version.cuda)
print(torch.cuda.is_available())
if torch.cuda.is_available():
    print(torch.cuda.get_device_name(0))
    print(torch.cuda.get_device_capability(0))
PY
assistant
exec_command
args
{
  "cmd": "find /workspace -maxdepth 4 -type d \\( -name '*cutlass*' -o -name '*triton*' \\) 2>/dev/null | head -50",
  "workdir": "/workspace/problems/01_fp8_gemm",
  "yield_time_ms": 1000,
  "max_output_tokens": 8000
}
tool
stdout (668 chars)
Chunk ID: 55930f
Wall time: 0.0000 seconds
Process exited with code 0
Original token count: 141
Output:
"""Canonical shape sweep for FP8 GEMM.

Mix of:
  - square aligned (the easy case)
  - off-alignment K (common real-world failure mode for tile-quantized kernels)
  - skinny (decode-like, memory-bound)
  - rectangular (prefill with grouped attention)
"""

SHAPES = [
    {"M": 4096, "N": 4096, "K": 4096},        # square aligned
    {"M": 4096, "N": 4096, "K": 4127},        # K not multiple of 128 -> forces predicated tails
    {"M": 32,   "N": 8192, "K": 8192},        # skinny M (decode)
    {"M": 4096, "N": 14336, "K": 4096},       # Llama3 up-proj shape
]
tool
stdout (1245 chars)
Chunk ID: 6ee11a
Wall time: 0.0000 seconds
Process exited with code 0
Original token count: 286
Output:
name: 01_fp8_gemm
display_name: "FP8 e4m3 GEMM"
precision: fp8_e4m3
regime: compute

# Dense-equivalent FLOPs per invocation. Evaluated per-shape; the benchmark
# substitutes M/N/K from each shapes.py entry.
flops_formula: "2 * M * N * K"

# Bytes moved (approximate): fp8 inputs in, bf16 output.
bytes_formula: "M*K + K*N + M*N*2"

hardware: [RTX_PRO_6000]
peak_tflops_key: fp8  # index into src/hardware/rtx_pro_6000.py peak_tflops_dense
peak_bandwidth_key: dram

# Per-dtype tolerance override (optional). Defaults are in src/eval/correctness.py.
tolerance:
  bfloat16: 0.2
  fp8_e4m3fn: 0.2

# Forbidden ops — using any of these in solution.py fails correctness post-hoc.
# torch._scaled_mm is Stanford-style cheating (just call the vendor library).
forbidden:
  - "torch._scaled_mm"
  - "torch.ops.aten._scaled_mm"

sota:
  name: "FlashInfer FP8 GEMM"
  url: "https://github.com/flashinfer-ai/flashinfer"
  function: "flashinfer.gemm.fp8_gemm"
  deps:
    - "flashinfer>=0.6.8"
  # Documented H100 throughput for this shape (informational, not graded):
  reference_throughput_tflops_h100: 550

num_correct_trials: 3
num_perf_trials: 30
tool
stdout (1827 chars) — TRUNCATED
Chunk ID: 2e7298
Wall time: 0.0000 seconds
Process exited with code 0
Original token count: 432
Output:
"""SOTA reference for FP8 GEMM: flashinfer.gemm.fp8_gemm.

If flashinfer is not installed or the SM120 path isn't supported, this falls
back to torch._scaled_mm which is the cuBLAS FP8 path. The benchmark treats
whichever succeeds as the SOTA reference line.

Agents are FORBIDDEN from using torch._scaled_mm in their solution (see
problem.yaml.forbidden). This file is only for the benchmark's reference line.
"""
from __future__ import annotations

import torch


def _try_flashinfer(x: torch.Tensor, w: torch.Tensor) -> torch.Tensor | None:
    try:
        import flashinfer  # noqa: F401
        # Note: flashinfer's FP8 GEMM API surface may differ; adapt if needed.
        # Placeholder call — replace with the actual flashinfer entry point
        # once validated on SM120.
        return None
    except ImportError:
        return None


def _scaled_mm(x: torch.Tensor, w: torch.Tensor) -> torch.Tensor:
    # torch._scaled_mm wants per-tensor scales. Use unit scales for the reference.
    scale_a = torch.tensor(1.0, device=x.device)
    scale_b = torch.tensor(1.0, device=x.device)
    out = torch._scaled_mm(
        x,
        w.T,
        scale_a=scale_a,
        scale_b=scale_b,
        out_dtype=torch.bfloat16,
    )
    return out if not isinstance(out, tuple) else out[0]


def sota_forward(x: torch.Tensor, w: torch.Tensor) -> torch.Tensor:
    """Best-available FP8 GEMM 

... (327 more chars)
tool
stdout (642 chars)
Chunk ID: 9e8778
Wall time: 1.0010 seconds
Process running with session ID 39318
Original token count: 132
Output:
Using CPython 3.11.15
Creating virtual environment at: /workspace/.venv
   Building kernelbench-hard @ file:///workspace
      Built kernelbench-hard @ file:///workspace
warning: Failed to hardlink files; falling back to full copy. This may lead to degraded performance.
         If the cache and target directories are on different filesystems, hardlinking may not be supported.
         If this is intentional, set `export UV_LINK_MODE=copy` or use `--link-mode=copy` to suppress this warning.
Installed 56 packages in 898ms
tool
stdout (102 chars)
Chunk ID: 1bdab4
Wall time: 0.0000 seconds
Process exited with code 0
Original token count: 0
Output:
assistant
write_stdin
args
{
  "session_id": 39318,
  "chars": "",
  "yield_time_ms": 1000,
  "max_output_tokens": 12000
}
tool
stdout (184 chars)
Chunk ID: 38ca8b
Wall time: 0.0000 seconds
Process exited with code 0
Original token count: 21
Output:
2.11.0+cu130
13.0
True
NVIDIA RTX PRO 6000 Blackwell Workstation Edition
(12, 0)
assistant
This is set up on the intended GPU with Torch 2.11 CUDA 13 and SM 12.0 visible. I’m going to start with a Triton FP8 tensor-core kernel because it keeps the source self-contained and can handle the K tail with masks; then I’ll tune by shape based on the harness timings.
assistant
exec_command
args
{
  "cmd": "<82 chars \u2014 see below>",
  "workdir": "/workspace/problems/01_fp8_gemm",
  "yield_time_ms": 1000,
  "max_output_tokens": 4000
}
cmd (82 chars)
uv run python - <<'PY'
import triton, torch
print('triton', triton.__version__)
PY
assistant
exec_command
args
{
  "cmd": "<85 chars \u2014 see below>",
  "workdir": "/workspace/problems/01_fp8_gemm",
  "yield_time_ms": 1000,
  "max_output_tokens": 6000
}
cmd (85 chars)
python - <<'PY'
import inspect, triton.language as tl
print(tl.dot.__doc__[:3000])
PY
tool
stdout (115 chars)
Chunk ID: e7a2a8
Wall time: 0.5626 seconds
Process exited with code 0
Original token count: 4
Output:
triton 3.6.0
tool
stdout (1681 chars) — TRUNCATED
Chunk ID: 6c6bcd
Wall time: 0.0000 seconds
Process exited with code 0
Original token count: 395
Output:

    Returns the matrix product of two blocks.

    The two blocks must both be two-dimensional or three-dimensional and have compatible inner dimensions.
    For three-dimensional blocks, `tl.dot` performs the batched matrix product,
    where the first dimension of each block represents the batch dimension.

    :param input: The first tensor to be multiplied.
    :type input: 2D or 3D tensor of scalar-type in {:code:`int8`, :code:`float8_e5m2`, :code:`float16`, :code:`bfloat16`, :code:`float32`}
    :param other: The second tensor to be multiplied.
    :type other: 2D or 3D tensor of scalar-type in {:code:`int8`, :code:`float8_e5m2`, :code:`float16`, :code:`bfloat16`, :code:`float32`}
    :param acc: The accumulator tensor. If not None, the result is added to this tensor.
    :type acc: 2D or 3D tensor of scalar-type in {:code:`float16`, :code:`float32`, :code:`int32`}
    :param input_precision: How to exercise the Tensor Cores for f32 x f32. If
      the device does not have Tensor Cores or the inputs are not of dtype f32,
      this option is ignored. For devices that do have tensor cores, the
      default precision is tf32.
    :type input_precision: string. Available options for nvidia: :code:`"tf32"`, :code:`"tf32x3"`, :code:`"ieee"`. Default: :code:`"tf32"`. Available options for amd: :code:`"ieee"`, (CDNA3 only) :code:`"tf32"`.
    :param allow_tf32: *Deprecated

... (181 more chars)
assistant
I’m writing the first kernel now: one Triton program computes a tile of `x @ weight.T`, accumulates in fp32, multiplies by `weight_scale` per column, and stores bf16. The launch wrapper will pick separate tile shapes for the skinny-M case versus the large-M cases.
assistant
apply_patch /workspace/problems/01_fp8_gemm/solution.py
diff (130 lines)
--- /dev/null
+++ b//workspace/problems/01_fp8_gemm/solution.py
@@ -0,0 +1,127 @@
+import torch
+import torch.nn as nn
+import triton
+import triton.language as tl
+
+
+E4M3_MAX = 448.0
+
+
+@triton.jit
+def _fp8_gemm_kernel(
+    x_ptr,
+    w_ptr,
+    scale_ptr,
+    y_ptr,
+    M: tl.constexpr,
+    N: tl.constexpr,
+    K: tl.constexpr,
+    BLOCK_M: tl.constexpr,
+    BLOCK_N: tl.constexpr,
+    BLOCK_K: tl.constexpr,
+    GROUP_M: tl.constexpr,
+):
+    pid = tl.program_id(0)
+    num_pid_m = tl.cdiv(M, BLOCK_M)
+    num_pid_n = tl.cdiv(N, BLOCK_N)
+    group_size = GROUP_M * num_pid_n
+    group_id = pid // group_size
+    first_pid_m = group_id * GROUP_M
+    group_m = tl.minimum(num_pid_m - first_pid_m, GROUP_M)
+    pid_in_group = pid - group_id * group_size
+    pid_m = first_pid_m + (pid_in_group % group_m)
+    pid_n = pid_in_group // group_m
+
+    offs_m = pid_m * BLOCK_M + tl.arange(0, BLOCK_M)
+    offs_n = pid_n * BLOCK_N + tl.arange(0, BLOCK_N)
+    offs_k = tl.arange(0, BLOCK_K)
+
+    acc = tl.zeros((BLOCK_M, BLOCK_N), tl.float32)
+    for k0 in range(0, K, BLOCK_K):
+        k = k0 + offs_k
+        a = tl.load(
+            x_ptr + offs_m[:, None] * K + k[None, :],
+            mask=(offs_m[:, None] < M) & (k[None, :] < K),
+            other=0.0,
+        )
+        b = tl.load(
+            w_ptr + offs_n[None, :] * K + k[:, None],
+            mask=(offs_n[None, :] < N) & (k[:, None] < K),
+            other=0.0,
+        )
+        acc = tl.dot(a, b, acc, out_dtype=tl.float32)
+
+    scales = tl.load(scale_ptr + offs_n, mask=offs_n < N, other=0.0)
+    acc = acc * scales[None, :]
+    tl.store(
+        y_ptr + offs_m[:, None] * N + offs_n[None, :],
+        acc,
+        mask=(offs_m[:, None] < M) & (offs_n[None, :] < N),
+    )
+
+
+def _launch_fp8_gemm(x: torch.Tensor, weight: torch.Tensor, weight_scale: torch.Tensor, M: int, N: int, K: int):
+    y = torch.empty((M, N), device=x.device, dtype=torch.bfloat16)
+
+    if M <= 64:
+        bm, bn, bk = 32, 128, 128
+        warps, stages, group_m = 4, 4, 4
+    elif N >= 8192:
+        bm, bn, bk = 128, 128, 128
+        warps, stages, group_m = 4, 4, 4
+    else:
+        bm, bn, bk = 128, 128, 128
+        warps, stages, group_m = 4, 4, 4
+
+    grid = (triton.cdiv(M, bm) * triton.cdiv(N, bn),)
+    _fp8_gemm_kernel[grid](
+        x,
+        weight,
+        weight_scale,
+        y,
+        M,
+        N,
+        K,
+        BLOCK_M=bm,
+        BLOCK_N=bn,
+        BLOCK_K=bk,
+        GROUP_M=group_m,
+        num_warps=warps,
+        num_stages=stages,
+    )
+    return y
+
+
+class Model(nn.Module):
+    def __init__(self, M: int, N: int, K: int):
+        super().__init__()
+        self.M, self.N, self.K = M, N, K
+        w = torch.empty(N, K, dtype=torch.bfloat16)
+        nn.init.normal_(w, std=0.02)
+        s = (w.float().abs().amax(dim=1, keepdim=True) / E4M3_MAX).clamp(min=1e-12)
+        w_fp8 = (w.float() / s).to(torch.float8_e4m3fn)
+        self.register_buffer("weight", w_fp8)
+        self.register_buffer("weight_scale", s.squeeze(1).to(torch.float32))
+
+    def forward(self, x: torch.Tensor) -> torch.Tensor:
+        if not x.is_cuda:
+            x_bf = x.to(torch.bfloat16)
+            w_bf = self.weight.to(torch.bfloat16)
+            y = (x_bf @ w_bf.T).float()
+            y = y * self.weight_scale[None, :]
+            return y.to(torch.bfloat16)
+        return _launch_fp8_gemm(x, self.weight, self.weight_scale, self.M, self.N, self.K)
+
+
+M = 4096
+N = 4096
+K = 4096
+
+
+def get_inputs():
+    x = (torch.rand(M, K) * 8 - 4).to(torch.float8_e4m3fn)
+    return [x]
+
+
+def get_init_inputs():
+    return [M, N, K]
args
{
  "raw": "<3703 chars \u2014 see below>"
}
raw (3703 chars)
*** Begin Patch
*** Add File: /workspace/problems/01_fp8_gemm/solution.py
+import torch
+import torch.nn as nn
+import triton
+import triton.language as tl
+
+
+E4M3_MAX = 448.0
+
+
+@triton.jit
+def _fp8_gemm_kernel(
+    x_ptr,
+    w_ptr,
+    scale_ptr,
+    y_ptr,
+    M: tl.constexpr,
+    N: tl.constexpr,
+    K: tl.constexpr,
+    BLOCK_M: tl.constexpr,
+    BLOCK_N: tl.constexpr,
+    BLOCK_K: tl.constexpr,
+    GROUP_M: tl.constexpr,
+):
+    pid = tl.program_id(0)
+    num_pid_m = tl.cdiv(M, BLOCK_M)
+    num_pid_n = tl.cdiv(N, BLOCK_N)
+    group_size = GROUP_M * num_pid_n
+    group_id = pid // group_size
+    first_pid_m = group_id * GROUP_M
+    group_m = tl.minimum(num_pid_m - first_pid_m, GROUP_M)
+    pid_in_group = pid - group_id * group_size
+    pid_m = first_pid_m + (pid_in_group % group_m)
+    pid_n = pid_in_group // group_m
+
+    offs_m = pid_m * BLOCK_M + tl.arange(0, BLOCK_M)
+    offs_n = pid_n * BLOCK_N + tl.arange(0, BLOCK_N)
+    offs_k = tl.arange(0, BLOCK_K)
+
+    acc = tl.zeros((BLOCK_M, BLOCK_N), tl.float32)
+    for k0 in range(0, K, BLOCK_K):
+        k = k0 + offs_k
+        a = tl.load(
+            x_ptr + offs_m[:, None] * K + k[None, :],
+            mask=(offs_m[:, None] < M) & (k[None, :] < K),
+            other=0.0,
+        )
+        b = tl.load(
+            w_ptr + offs_n[None, :] * K + k[:, None],
+            mask=(offs_n[None, :] < N) & (k[:, None] < K),
+            other=0.0,
+        )
+        acc = tl.dot(a, b, acc, out_dtype=tl.float32)
+
+    scales = tl.load(scale_ptr + offs_n, mask=offs_n < N, other=0.0)
+    acc = acc * scales[None, :]
+    tl.store(
+        y_ptr + offs_m[:, None] * N + offs_n[None, :],
+        acc,
+        mask=(offs_m[:, None] < M) & (offs_n[None, :] < N),
+    )
+
+
+def _launch_fp8_gemm(x: torch.Tensor, weight: torch.Tensor, weight_scale: torch.Tensor, M: int, N: int, K: int):
+    y = torch.empty((M, N), device=x.device, dtype=torch.bfloat16)
+
+    if M <= 64:
+        bm, bn, bk = 32, 128, 128
+        warps, stages, group_m = 4, 4, 4
+    elif N >= 8192:
+        bm, bn, bk = 128, 128, 128
+        warps, stages, group_m = 4, 4, 4
+    else:
+        bm, bn, bk = 128, 128, 128
+        warps, stages, group_m = 4, 4, 4
+
+    grid = (triton.cdiv(M, bm) * triton.cdiv(N, bn),)
+    _fp8_gemm_kernel[grid](
+        x,
+        weight,
+        weight_scale,
+        y,
+        M,
+        N,
+        K,
+        BLOCK_M=bm,
+        BLOCK_N=bn,
+        BLOCK_K=bk,
+        GROUP_M=group_m,
+        num_warps=warps,
+        num_stages=stages,
+    )
+    return y
+
+
+class Model(nn.Module):
+    def __init__(self, M: int, N: int, K: int):
+        super().__init__()
+        self.M, self.N, self.K = M, N, K
+        w = torch.empty(N, K, dtype=torch.bfloat16)
+        nn.init.normal_(w, std=0.02)
+        s = (w.float().abs().amax(dim=1, keepdim=True) / E4M3_MAX).clamp(min=1e-12)
+        w_fp8 = (w.float() / s).to(torch.float8_e4m3fn)
+        self.register_buffer("weight", w_fp8)
+        self.register_buffer("weight_scale", s.squeeze(1).to(torch.float32))
+
+    def forward(self, x: torch.Tensor) -> torch.Tensor:
+        if not x.is_cuda:
+            x_bf = x.to(torch.bfloat16)
+            w_bf = self.weight.to(torch.bfloat16)
+            y = (x_bf @ w_bf.T).float()
+            y = y * self.weight_scale[None, :]
+            return y.to(torch.bfloat16)
+        return _launch_fp8_gemm(x, self.weight, self.weight_scale, self.M, self.N, self.K)
+
+
+M = 4096
+N = 4096
+K = 4096
+
+
+def get_inputs():
+    x = (torch.rand(M, K) * 8 - 4).to(torch.float8_e4m3fn)
+    return [x]
+
+
+def get_init_inputs():
+    return [M, N, K]
*** End Patch
tool
stdout (144 chars)
output:
  Success. Updated the following files:
  A /workspace/problems/01_fp8_gemm/solution.py
metadata:
  exit_code: 0
  duration_seconds: 0.0
assistant
The first implementation is in place. I’m running the full correctness harness now; this will also flush out whether Triton’s FP8 lowering is using the expected dtype path on this Torch/Triton build.
assistant
exec_command
args
{
  "cmd": "uv run python check.py",
  "workdir": "/workspace/problems/01_fp8_gemm",
  "yield_time_ms": 1000,
  "max_output_tokens": 20000
}
tool
stdout (113 chars)
Chunk ID: 7be9ac
Wall time: 1.0011 seconds
Process running with session ID 48928
Original token count: 0
Output:
assistant
write_stdin
args
{
  "session_id": 48928,
  "chars": "",
  "yield_time_ms": 1000,
  "max_output_tokens": 20000
}
tool
stdout (107 chars)
Chunk ID: ac9a37
Wall time: 4.1047 seconds
Process exited with code 0
Original token count: 2
Output:
PASS
assistant
Correctness passes across the harness. Next I’m measuring the four target shapes so we can see where the first kernel is weak before tuning tile sizes or adding shape-specific paths.
assistant
exec_command
args
{
  "cmd": "uv run python benchmark.py",
  "workdir": "/workspace/problems/01_fp8_gemm",
  "yield_time_ms": 1000,
  "max_output_tokens": 20000
}
tool
stdout (211 chars)
Chunk ID: 293d9e
Wall time: 1.0016 seconds
Process running with session ID 96982
Original token count: 25
Output:
benchmark_event event=variant_start shape=0 variant=solution ts=2026-06-14T20:43:53.821152+00:00
assistant
write_stdin
args
{
  "session_id": 96982,
  "chars": "",
  "yield_time_ms": 1000,
  "max_output_tokens": 20000
}
tool
stdout (1320 chars)
Chunk ID: 04cbaa
Wall time: 2.4324 seconds
Process exited with code 0
Original token count: 304
Output:
benchmark_event event=variant_end shape=0 variant=solution ts=2026-06-14T20:43:54.027282+00:00 elapsed_s=0.206 ms=0.232752
shape=0 variant=solution tflops=590.495 gbps=288.328 ms=0.233
shape=0 solution_peak_fraction=0.5905
benchmark_event event=variant_start shape=1 variant=solution ts=2026-06-14T20:43:54.531053+00:00
benchmark_event event=variant_end shape=1 variant=solution ts=2026-06-14T20:43:54.556362+00:00 elapsed_s=0.025 ms=0.550112
shape=1 variant=solution tflops=251.729 gbps=122.453 ms=0.550
shape=1 solution_peak_fraction=0.2517
benchmark_event event=variant_start shape=2 variant=solution ts=2026-06-14T20:43:56.394376+00:00
benchmark_event event=variant_end shape=2 variant=solution ts=2026-06-14T20:43:56.399965+00:00 elapsed_s=0.006 ms=0.060336
shape=2 variant=solution tflops=71.184 gbps=1125.287 ms=0.060
shape=2 solution_peak_fraction=0.0712
benchmark_event event=variant_start shape=3 variant=solution ts=2026-06-14T20:43:58.058735+00:00
benchmark_event event=variant_end shape=3 variant=solution ts=2026-06-14T20:43:58.092450+00:00 elapsed_s=0.034 ms=0.736592
shape=3 variant=solution tflops=653.057 gbps=261.933 ms=0.737
shape=3 solution_peak_fraction=0.6531
peak_fraction: 0.2883
RESULT: OK
assistant
The initial result is decent on aligned large GEMMs, but the K=4127 case collapses because the current loop keeps K-tail masks on every block. I’m splitting the kernel into an unmasked full-K main loop plus a single masked tail block, which should matter specifically for that off-alignment shape.
assistant
apply_patch /workspace/problems/01_fp8_gemm/solution.py
diff (141 lines)
--- a//workspace/problems/01_fp8_gemm/solution.py
+++ b//workspace/problems/01_fp8_gemm/solution.py
@@ -1,127 +1,22 @@
-import torch
-import torch.nn as nn
-import triton
-import triton.language as tl
+    acc = tl.zeros((BLOCK_M, BLOCK_N), tl.float32)
+    full_k = (K // BLOCK_K) * BLOCK_K
+    for k0 in range(0, full_k, BLOCK_K):
+        k = k0 + offs_k
+        a = tl.load(x_ptr + offs_m[:, None] * K + k[None, :])
+        b = tl.load(w_ptr + offs_n[None, :] * K + k[:, None])
+        acc = tl.dot(a, b, acc, out_dtype=tl.float32)
 
-
-E4M3_MAX = 448.0
-
-
-@triton.jit
-def _fp8_gemm_kernel(
-    x_ptr,
-    w_ptr,
-    scale_ptr,
-    y_ptr,
-    M: tl.constexpr,
-    N: tl.constexpr,
-    K: tl.constexpr,
-    BLOCK_M: tl.constexpr,
-    BLOCK_N: tl.constexpr,
-    BLOCK_K: tl.constexpr,
-    GROUP_M: tl.constexpr,
-):
-    pid = tl.program_id(0)
-    num_pid_m = tl.cdiv(M, BLOCK_M)
-    num_pid_n = tl.cdiv(N, BLOCK_N)
-    group_size = GROUP_M * num_pid_n
-    group_id = pid // group_size
-    first_pid_m = group_id * GROUP_M
-    group_m = tl.minimum(num_pid_m - first_pid_m, GROUP_M)
-    pid_in_group = pid - group_id * group_size
-    pid_m = first_pid_m + (pid_in_group % group_m)
-    pid_n = pid_in_group // group_m
-
-    offs_m = pid_m * BLOCK_M + tl.arange(0, BLOCK_M)
-    offs_n = pid_n * BLOCK_N + tl.arange(0, BLOCK_N)
-    offs_k = tl.arange(0, BLOCK_K)
-
-    acc = tl.zeros((BLOCK_M, BLOCK_N), tl.float32)
-    for k0 in range(0, K, BLOCK_K):
-        k = k0 + offs_k
+    if full_k < K:
+        k = full_k + offs_k
         a = tl.load(
             x_ptr + offs_m[:, None] * K + k[None, :],
-            mask=(offs_m[:, None] < M) & (k[None, :] < K),
+            mask=k[None, :] < K,
             other=0.0,
         )
         b = tl.load(
             w_ptr + offs_n[None, :] * K + k[:, None],
-            mask=(offs_n[None, :] < N) & (k[:, None] < K),
+            mask=k[:, None] < K,
             other=0.0,
         )
         acc = tl.dot(a, b, acc, out_dtype=tl.float32)
 
-    scales = tl.load(scale_ptr + offs_n, mask=offs_n < N, other=0.0)
-    acc = acc * scales[None, :]
-    tl.store(
-        y_ptr + offs_m[:, None] * N + offs_n[None, :],
-        acc,
-        mask=(offs_m[:, None] < M) & (offs_n[None, :] < N),
-    )
-
-
-def _launch_fp8_gemm(x: torch.Tensor, weight: torch.Tensor, weight_scale: torch.Tensor, M: int, N: int, K: int):
-    y = torch.empty((M, N), device=x.device, dtype=torch.bfloat16)
-
-    if M <= 64:
-        bm, bn, bk = 32, 128, 128
-        warps, stages, group_m = 4, 4, 4
-    elif N >= 8192:
-        bm, bn, bk = 128, 128, 128
-        warps, stages, group_m = 4, 4, 4
-    else:
-        bm, bn, bk = 128, 128, 128
-        warps, stages, group_m = 4, 4, 4
-
-    grid = (triton.cdiv(M, bm) * triton.cdiv(N, bn),)
-    _fp8_gemm_kernel[grid](
-        x,
-        weight,
-        weight_scale,
-        y,
-        M,
-        N,
-        K,
-        BLOCK_M=bm,
-        BLOCK_N=bn,
-        BLOCK_K=bk,
-        GROUP_M=group_m,
-        num_warps=warps,
-        num_stages=stages,
-    )
-    return y
-
-
-class Model(nn.Module):
-    def __init__(self, M: int, N: int, K: int):
-        super().__init__()
-        self.M, self.N, self.K = M, N, K
-        w = torch.empty(N, K, dtype=torch.bfloat16)
-        nn.init.normal_(w, std=0.02)
-        s = (w.float().abs().amax(dim=1, keepdim=True) / E4M3_MAX).clamp(min=1e-12)
-        w_fp8 = (w.float() / s).to(torch.float8_e4m3fn)
-        self.register_buffer("weight", w_fp8)
-        self.register_buffer("weight_scale", s.squeeze(1).to(torch.float32))
-
-    def forward(self, x: torch.Tensor) -> torch.Tensor:
-        if not x.is_cuda:
-            x_bf = x.to(torch.bfloat16)
-            w_bf = self.weight.to(torch.bfloat16)
-            y = (x_bf @ w_bf.T).float()
-            y = y * self.weight_scale[None, :]
-            return y.to(torch.bfloat16)
-        return _launch_fp8_gemm(x, self.weight, self.weight_scale, self.M, self.N, self.K)
-
-
-M = 4096
-N = 4096
-K = 4096
-
-
-def get_inputs():
-    x = (torch.rand(M, K) * 8 - 4).to(torch.float8_e4m3fn)
-    return [x]
-
-
-def get_init_inputs():
-    return [M, N, K]
args
{
  "raw": "<1266 chars \u2014 see below>"
}
raw (1266 chars)
*** Begin Patch
*** Update File: /workspace/problems/01_fp8_gemm/solution.py
@@
-    acc = tl.zeros((BLOCK_M, BLOCK_N), tl.float32)
-    for k0 in range(0, K, BLOCK_K):
+    acc = tl.zeros((BLOCK_M, BLOCK_N), tl.float32)
+    full_k = (K // BLOCK_K) * BLOCK_K
+    for k0 in range(0, full_k, BLOCK_K):
         k = k0 + offs_k
-        a = tl.load(
-            x_ptr + offs_m[:, None] * K + k[None, :],
-            mask=(offs_m[:, None] < M) & (k[None, :] < K),
-            other=0.0,
-        )
-        b = tl.load(
-            w_ptr + offs_n[None, :] * K + k[:, None],
-            mask=(offs_n[None, :] < N) & (k[:, None] < K),
-            other=0.0,
-        )
+        a = tl.load(x_ptr + offs_m[:, None] * K + k[None, :])
+        b = tl.load(w_ptr + offs_n[None, :] * K + k[:, None])
         acc = tl.dot(a, b, acc, out_dtype=tl.float32)
 
+    if full_k < K:
+        k = full_k + offs_k
+        a = tl.load(
+            x_ptr + offs_m[:, None] * K + k[None, :],
+            mask=k[None, :] < K,
+            other=0.0,
+        )
+        b = tl.load(
+            w_ptr + offs_n[None, :] * K + k[:, None],
+            mask=k[:, None] < K,
+            other=0.0,
+        )
+        acc = tl.dot(a, b, acc, out_dtype=tl.float32)
+
*** End Patch
tool
stdout (144 chars)
output:
  Success. Updated the following files:
  M /workspace/problems/01_fp8_gemm/solution.py
metadata:
  exit_code: 0
  duration_seconds: 0.0
assistant
The main loop is now unmasked for full 128-wide K chunks, with only the final partial chunk predicated. I’m re-running correctness before timing because this removes boundary masks and assumes the fixed target M/N tile divisibility.
assistant
exec_command
args
{
  "cmd": "uv run python check.py",
  "workdir": "/workspace/problems/01_fp8_gemm",
  "yield_time_ms": 1000,
  "max_output_tokens": 20000
}
tool
stdout (113 chars)
Chunk ID: d37e6e
Wall time: 1.0010 seconds
Process running with session ID 37740
Original token count: 0
Output:
assistant
write_stdin
args
{
  "session_id": 37740,
  "chars": "",
  "yield_time_ms": 1000,
  "max_output_tokens": 20000
}
tool
stdout (113 chars)
Chunk ID: 150b57
Wall time: 5.0011 seconds
Process running with session ID 37740
Original token count: 0
Output:
assistant
write_stdin
args
{
  "session_id": 37740,
  "chars": "",
  "yield_time_ms": 1000,
  "max_output_tokens": 20000
}
tool
stdout (113 chars)
Chunk ID: 51ba8b
Wall time: 5.0003 seconds
Process running with session ID 37740
Original token count: 0
Output:
assistant
write_stdin
args
{
  "session_id": 37740,
  "chars": "",
  "yield_time_ms": 1000,
  "max_output_tokens": 20000
}
tool
stdout (107 chars)
Chunk ID: 9c678f
Wall time: 0.0000 seconds
Process exited with code 0
Original token count: 2
Output:
PASS
assistant
Correctness still passes. I’m timing again to confirm whether the off-alignment K path recovered without hurting the aligned shapes.
assistant
exec_command
args
{
  "cmd": "uv run python benchmark.py",
  "workdir": "/workspace/problems/01_fp8_gemm",
  "yield_time_ms": 1000,
  "max_output_tokens": 20000
}
tool
stdout (112 chars)
Chunk ID: 4674d5
Wall time: 1.0011 seconds
Process running with session ID 9985
Original token count: 0
Output:
assistant
write_stdin
args
{
  "session_id": 9985,
  "chars": "",
  "yield_time_ms": 1000,
  "max_output_tokens": 20000
}
tool
stdout (716 chars)
Chunk ID: f2f4af
Wall time: 5.0016 seconds
Process running with session ID 9985
Original token count: 151
Output:
benchmark_event event=variant_start shape=0 variant=solution ts=2026-06-14T20:45:01.578316+00:00
benchmark_event event=variant_end shape=0 variant=solution ts=2026-06-14T20:45:01.782619+00:00 elapsed_s=0.204 ms=0.234336
shape=0 variant=solution tflops=586.504 gbps=286.379 ms=0.234
shape=0 solution_peak_fraction=0.5865
benchmark_event event=variant_start shape=1 variant=solution ts=2026-06-14T20:45:02.291965+00:00
benchmark_event event=variant_end shape=1 variant=solution ts=2026-06-14T20:45:02.312549+00:00 elapsed_s=0.021 ms=0.430192
shape=1 variant=solution tflops=321.901 gbps=156.588 ms=0.430
assistant
write_stdin
args
{
  "session_id": 9985,
  "chars": "",
  "yield_time_ms": 1000,
  "max_output_tokens": 20000
}
tool
stdout (815 chars)
Chunk ID: cd9b6f
Wall time: 0.0000 seconds
Process exited with code 0
Original token count: 178
Output:
shape=1 solution_peak_fraction=0.3219
benchmark_event event=variant_start shape=2 variant=solution ts=2026-06-14T20:45:04.158884+00:00
benchmark_event event=variant_end shape=2 variant=solution ts=2026-06-14T20:45:04.164553+00:00 elapsed_s=0.006 ms=0.060528
shape=2 variant=solution tflops=70.958 gbps=1121.717 ms=0.061
shape=2 solution_peak_fraction=0.0710
benchmark_event event=variant_start shape=3 variant=solution ts=2026-06-14T20:45:05.829763+00:00
benchmark_event event=variant_end shape=3 variant=solution ts=2026-06-14T20:45:05.862916+00:00 elapsed_s=0.033 ms=0.740976
shape=3 variant=solution tflops=649.193 gbps=260.384 ms=0.741
shape=3 solution_peak_fraction=0.6492
peak_fraction: 0.3054
RESULT: OK
assistant
The tail split improved K=4127 from about 252 to 322 TFLOP/s, but there is still headroom. I’m going to collect the optional baselines now so we know whether the remaining gap is Triton tiling, layout/alignment, or a general harness overhead issue.
assistant
exec_command
args
{
  "cmd": "KBH_BENCHMARK_BASELINES=1 uv run python benchmark.py",
  "workdir": "/workspace/problems/01_fp8_gemm",
  "yield_time_ms": 1000,
  "max_output_tokens": 30000
}
tool
stdout (211 chars)
Chunk ID: eef1ec
Wall time: 1.0018 seconds
Process running with session ID 34539
Original token count: 25
Output:
benchmark_event event=variant_start shape=0 variant=solution ts=2026-06-14T20:45:11.715233+00:00
assistant
write_stdin
args
{
  "session_id": 34539,
  "chars": "",
  "yield_time_ms": 1000,
  "max_output_tokens": 30000
}
tool
stdout (3488 chars) — TRUNCATED
Chunk ID: 07b691
Wall time: 5.0012 seconds
Process running with session ID 34539
Original token count: 844
Output:
benchmark_event event=variant_end shape=0 variant=solution ts=2026-06-14T20:45:11.923134+00:00 elapsed_s=0.208 ms=0.234048
shape=0 variant=solution tflops=587.225 gbps=286.731 ms=0.234
benchmark_event event=variant_start shape=0 variant=eager ts=2026-06-14T20:45:11.923163+00:00
benchmark_event event=variant_end shape=0 variant=eager ts=2026-06-14T20:45:12.010443+00:00 elapsed_s=0.087 ms=0.503952
benchmark_event event=variant_start shape=0 variant=compiled ts=2026-06-14T20:45:14.229071+00:00
benchmark_event event=variant_end shape=0 variant=compiled ts=2026-06-14T20:45:14.995085+00:00 elapsed_s=0.766 ms=0.427440
benchmark_event event=variant_start shape=0 variant=sota ts=2026-06-14T20:45:14.995113+00:00
benchmark_event event=variant_end shape=0 variant=sota ts=2026-06-14T20:45:15.009660+00:00 elapsed_s=0.015 ms=0.257216
shape=0 variant=eager tflops=272.722 gbps=133.165 ms=0.504
shape=0 variant=compiled tflops=321.540 gbps=157.002 ms=0.427
shape=0 variant=sota tflops=534.333 gbps=260.905 ms=0.257
shape=0 solution_peak_fraction=0.5872
benchmark_event event=variant_start shape=1 variant=solution ts=2026-06-14T20:45:15.530311+00:00
benchmark_event event=variant_end shape=1 variant=solution ts=2026-06-14T20:45:16.011439+00:00 elapsed_s=0.481 ms=0.430160
shape=1 variant=solution tflops=321.925 gbps=156.599 ms=0.430
benchmark_event event=variant_start shape=1 variant=eag

... (1988 more chars)
assistant
The baseline data says our aligned large path is already faster than the available `_scaled_mm` line here, and the skinny path is faster too. The main outlier remains K=4127; `_scaled_mm` cannot handle that shape, so this needs kernel-side tuning rather than calling into a library.
assistant
write_stdin
args
{
  "session_id": 34539,
  "chars": "",
  "yield_time_ms": 1000,
  "max_output_tokens": 30000
}
tool
stdout (1319 chars)
Chunk ID: 765940
Wall time: 0.2911 seconds
Process exited with code 0
Original token count: 304
Output:
shape=2 solution_peak_fraction=0.0720
benchmark_event event=variant_start shape=3 variant=solution ts=2026-06-14T20:45:20.599084+00:00
benchmark_event event=variant_end shape=3 variant=solution ts=2026-06-14T20:45:20.806348+00:00 elapsed_s=0.207 ms=0.742672
shape=3 variant=solution tflops=647.710 gbps=259.789 ms=0.743
benchmark_event event=variant_start shape=3 variant=eager ts=2026-06-14T20:45:20.806372+00:00
benchmark_event event=variant_end shape=3 variant=eager ts=2026-06-14T20:45:20.892633+00:00 elapsed_s=0.086 ms=2.087648
benchmark_event event=variant_start shape=3 variant=compiled ts=2026-06-14T20:45:20.894092+00:00
benchmark_event event=variant_end shape=3 variant=compiled ts=2026-06-14T20:45:21.325365+00:00 elapsed_s=0.431 ms=1.434256
benchmark_event event=variant_start shape=3 variant=sota ts=2026-06-14T20:45:21.325394+00:00
benchmark_event event=variant_end shape=3 variant=sota ts=2026-06-14T20:45:21.357147+00:00 elapsed_s=0.032 ms=0.737904
shape=3 variant=eager tflops=230.420 gbps=92.419 ms=2.088
shape=3 variant=compiled tflops=335.391 gbps=134.521 ms=1.434
shape=3 variant=sota tflops=651.896 gbps=261.468 ms=0.738
shape=3 solution_peak_fraction=0.6477
peak_fraction: 0.3065
RESULT: OK
assistant
I’m moving into tile tuning. The key knobs are `BLOCK_M/N/K`, warps, stages, and M-grouping; I’ll time a constrained set directly against the same shapes so we don’t overfit one case and damage another.
assistant
exec_command
args
{
  "cmd": "<2696 chars \u2014 see below>",
  "workdir": "/workspace/problems/01_fp8_gemm",
  "yield_time_ms": 1000,
  "max_output_tokens": 40000
}
cmd (2696 chars)
uv run python - <<'PY'
import itertools, math, time
import torch, triton
import reference, solution
from src.eval.timing import time_variant
from src.eval.roofline import compute_tflops, compute_gbps
import shapes

torch.manual_seed(0)
device='cuda'

def run_shape(shape_idx, configs):
    shape=shapes.SHAPES[shape_idx]
    reference.M, reference.N, reference.K = shape['M'], shape['N'], shape['K']
    M,N,K=shape['M'], shape['N'], shape['K']
    ref=reference.Model(M,N,K).to(device).eval()
    x=reference.get_inputs()[0].to(device)
    # compile/warm default to avoid initialization noise
    print('\nshape', shape_idx, shape, flush=True)
    best=[]
    for cfg in configs:
        bm,bn,bk,warps,stages,gm=cfg
        if M % bm or N % bn: continue
        y=torch.empty((M,N),device=device,dtype=torch.bfloat16)
        grid=(triton.cdiv(M,bm)*triton.cdiv(N,bn),)
        def fn(inp=x, w=ref.weight, s=ref.weight_scale, out=y):
            solution._fp8_gemm_kernel[grid](inp,w,s,out,M,N,K,BLOCK_M=bm,BLOCK_N=bn,BLOCK_K=bk,GROUP_M=gm,num_warps=warps,num_stages=stages)
            return out
        try:
            # warm/compile
            for _ in range(3): fn()
            torch.cuda.synchronize()
            start=torch.cuda.Event(enable_timing=True); end=torch.cuda.Event(enable_timing=True)
            times=[]
            for _ in range(20):
                start.record(); fn(); end.record(); end.synchronize(); times.append(start.elapsed_time(end))
            ms=sorted(times)[len(times)//2]
            tflops=compute_tflops(2*M*N*K, ms)
            best.append((ms,tflops,cfg))
            print(f'cfg={cfg} ms={ms:.4f} tflops={tflops:.1f}', flush=True)
        except Exception as e:
            print(f'cfg={cfg} ERR {type(e).__name__}: {e}', flush=True)
            torch.cuda.synchronize()
    best.sort()
    print('BEST')
    for ms,t,cfg in best[:8]:
        print(f'  {cfg} ms={ms:.4f} tflops={t:.1f}')

large=[]
for bm,bn,bk in itertools.product([64,128,256],[64,128,256],[64,128,256]):
    if bm*bn > 32768: continue
    if bm == 256 and bn == 256: continue
    for warps in [4,8]:
      for stages in [3,4,5]:
        for gm in [2,4,8]:
          large.append((bm,bn,bk,warps,stages,gm))
# prioritize plausible subset to reduce compiles
large=[c for c in large if (c[0],c[1]) in [(128,128),(64,128),(128,64),(64,256),(256,64),(128,256),(256,128)]]
# fewer variants first
large=large[:]
run_shape(0, large[:80])
run_shape(1, large[:80])

skinny=[]
for bn,bk in itertools.product([64,128,256,512],[64,128,256]):
  for warps in [4,8]:
    for stages in [3,4,5]:
      for gm in [1,2,4,8]:
        skinny.append((32,bn,bk,warps,stages,gm))
run_shape(2, skinny)
PY
tool
stdout (113 chars)
Chunk ID: f280a2
Wall time: 1.0010 seconds
Process running with session ID 26164
Original token count: 0
Output:
assistant
write_stdin
args
{
  "session_id": 26164,
  "chars": "",
  "yield_time_ms": 1000,
  "max_output_tokens": 40000
}
tool
stdout (113 chars)
Chunk ID: 39ad1b
Wall time: 5.0014 seconds
Process running with session ID 26164
Original token count: 0
Output:
assistant
write_stdin
args
{
  "session_id": 26164,
  "chars": "",
  "yield_time_ms": 1000,
  "max_output_tokens": 40000
}
tool
stdout (113 chars)
Chunk ID: 758577
Wall time: 5.0011 seconds
Process running with session ID 26164
Original token count: 0
Output:
assistant
The tuning run is compiling and timing many Triton specializations, so it may sit quiet between variants. I’ve limited the search to plausible tile shapes first; if it finds a clear winner I’ll bake only those configs into `solution.py`.
assistant
write_stdin
args
{
  "session_id": 26164,
  "chars": "",
  "yield_time_ms": 1000,
  "max_output_tokens": 40000
}
tool
stdout (3245 chars) — TRUNCATED
Chunk ID: 351785
Wall time: 5.0007 seconds
Process running with session ID 26164
Original token count: 783
Output:

shape 0 {'M': 4096, 'N': 4096, 'K': 4096}
cfg=(64, 128, 64, 4, 3, 2) ms=0.2320 tflops=592.4
cfg=(64, 128, 64, 4, 3, 4) ms=0.2310 tflops=595.0
cfg=(64, 128, 64, 4, 3, 8) ms=0.2319 tflops=592.7
cfg=(64, 128, 64, 4, 4, 2) ms=0.2340 tflops=587.2
cfg=(64, 128, 64, 4, 4, 4) ms=0.2340 tflops=587.4
cfg=(64, 128, 64, 4, 4, 8) ms=0.2341 tflops=587.1
cfg=(64, 128, 64, 4, 5, 2) ms=0.2352 tflops=584.4
cfg=(64, 128, 64, 4, 5, 4) ms=0.2344 tflops=586.3
cfg=(64, 128, 64, 4, 5, 8) ms=0.2350 tflops=584.9
cfg=(64, 128, 64, 8, 3, 2) ms=0.2391 tflops=574.8
cfg=(64, 128, 64, 8, 3, 4) ms=0.2400 tflops=572.6
cfg=(64, 128, 64, 8, 3, 8) ms=0.2401 tflops=572.5
cfg=(64, 128, 64, 8, 4, 2) ms=0.2408 tflops=570.8
cfg=(64, 128, 64, 8, 4, 4) ms=0.2403 tflops=571.9
cfg=(64, 128, 64, 8, 4, 8) ms=0.2404 tflops=571.7
cfg=(64, 128, 64, 8, 5, 2) ms=0.2415 tflops=569.2
cfg=(64, 128, 64, 8, 5, 4) ms=0.2422 tflops=567.4
cfg=(64, 128, 64, 8, 5, 8) ms=0.2420 tflops=567.8
cfg=(64, 128, 128, 4, 3, 2) ms=0.2249 tflops=611.1
cfg=(64, 128, 128, 4, 3, 4) ms=0.2247 tflops=611.7
cfg=(64, 128, 128, 4, 3, 8) ms=0.2241 tflops=613.3
cfg=(64, 128, 128, 4, 4, 2) ms=0.2338 tflops=587.9
cfg=(64, 128, 128, 4, 4, 4) ms=0.2340 tflops=587.2
cfg=(64, 128, 128, 4, 4, 8) ms=0.2341 tflops=587.0
cfg=(64, 128, 128, 4, 5, 2) ms=0.2352 tflops=584.3
cfg=(64, 128, 128, 4, 5, 4) ms=0.2352 tflops=584.3
cfg=(64, 128, 128, 4, 5, 8) ms=0.2

... (1745 more chars)
assistant
write_stdin
args
{
  "session_id": 26164,
  "chars": "",
  "yield_time_ms": 1000,
  "max_output_tokens": 40000
}
tool
stdout (3860 chars) — TRUNCATED
Chunk ID: a758ef
Wall time: 5.0005 seconds
Process running with session ID 26164
Original token count: 937
Output:
cfg=(64, 128, 256, 8, 3, 8) ms=0.2424 tflops=567.0
cfg=(64, 128, 256, 8, 4, 2) ERR OutOfResources: out of resource: shared memory, Required: 147456, Hardware limit: 101376. Reducing block sizes or `num_stages` may help.
cfg=(64, 128, 256, 8, 4, 4) ERR OutOfResources: out of resource: shared memory, Required: 147456, Hardware limit: 101376. Reducing block sizes or `num_stages` may help.
cfg=(64, 128, 256, 8, 4, 8) ERR OutOfResources: out of resource: shared memory, Required: 147456, Hardware limit: 101376. Reducing block sizes or `num_stages` may help.
cfg=(64, 128, 256, 8, 5, 2) ERR OutOfResources: out of resource: shared memory, Required: 196608, Hardware limit: 101376. Reducing block sizes or `num_stages` may help.
cfg=(64, 128, 256, 8, 5, 4) ERR OutOfResources: out of resource: shared memory, Required: 196608, Hardware limit: 101376. Reducing block sizes or `num_stages` may help.
cfg=(64, 128, 256, 8, 5, 8) ERR OutOfResources: out of resource: shared memory, Required: 196608, Hardware limit: 101376. Reducing block sizes or `num_stages` may help.
cfg=(64, 256, 64, 4, 3, 2) ms=0.2153 tflops=638.4
cfg=(64, 256, 64, 4, 3, 4) ms=0.2156 tflops=637.5
cfg=(64, 256, 64, 4, 3, 8) ms=0.2149 tflops=639.5
cfg=(64, 256, 64, 4, 4, 2) ms=0.2238 tflops=614.0
cfg=(64, 256, 64, 4, 4, 4) ms=0.2228 tflops=616.7
cfg=(64, 256, 64, 4, 4, 8) ms=0.2228 tflops=616.7
cfg=(64, 256, 64, 4,

... (2360 more chars)
assistant
A useful result is emerging for the aligned square case: `64x256x64` is faster than the original `128x128x128`, roughly 640 TFLOP/s in the tuner. The same family is bad for K=4127, so the final wrapper will need shape-specific configs rather than one global tile.
assistant
write_stdin
args
{
  "session_id": 26164,
  "chars": "",
  "yield_time_ms": 5000,
  "max_output_tokens": 40000
}
tool
stdout (1736 chars) — TRUNCATED
Chunk ID: 602164
Wall time: 5.0018 seconds
Process running with session ID 26164
Original token count: 406
Output:
cfg=(64, 128, 64, 4, 5, 4) ms=0.9068 tflops=152.7
cfg=(64, 128, 64, 4, 5, 8) ms=0.9059 tflops=152.9
cfg=(64, 128, 64, 8, 3, 2) ms=0.6275 tflops=220.7
cfg=(64, 128, 64, 8, 3, 4) ms=0.6272 tflops=220.8
cfg=(64, 128, 64, 8, 3, 8) ms=0.6270 tflops=220.8
cfg=(64, 128, 64, 8, 4, 2) ms=0.6281 tflops=220.5
cfg=(64, 128, 64, 8, 4, 4) ms=0.6263 tflops=221.1
cfg=(64, 128, 64, 8, 4, 8) ms=0.6280 tflops=220.5
cfg=(64, 128, 64, 8, 5, 2) ms=0.6284 tflops=220.4
cfg=(64, 128, 64, 8, 5, 4) ms=0.6274 tflops=220.7
cfg=(64, 128, 64, 8, 5, 8) ms=0.6277 tflops=220.6
cfg=(64, 128, 128, 4, 3, 2) ms=0.4915 tflops=281.8
cfg=(64, 128, 128, 4, 3, 4) ms=0.4902 tflops=282.5
cfg=(64, 128, 128, 4, 3, 8) ms=0.4903 tflops=282.4
cfg=(64, 128, 128, 4, 4, 2) ms=0.4902 tflops=282.5
cfg=(64, 128, 128, 4, 4, 4) ms=0.4903 tflops=282.4
cfg=(64, 128, 128, 4, 4, 8) ms=0.4903 tflops=282.5
cfg=(64, 128, 128, 4, 5, 2) ms=0.4908 tflops=282.2
cfg=(64, 128, 128, 4, 5, 4) ms=0.4901 tflops=282.5
cfg=(64, 128, 128, 4, 5, 8) ms=0.4907 tflops=282.2
cfg=(64, 128, 128, 8, 3, 2) ms=0.5781 tflops=239.5
cfg=(64, 128, 128, 8, 3, 4) ms=0.5761 tflops=240.4
cfg=(64, 128, 128, 8, 3, 8) ms=0.5769 tflops=240.0
cfg=(64, 128, 128, 8, 4, 2) ms=0.5783 tflops=239.5
cfg=(64, 128, 128, 8, 4, 4) ms=0.5762 tflops=240.3
cfg=(64, 128, 128, 8, 4, 8) ms=0.5761 tflops=240.4
cfg=(64, 128, 128, 8, 5, 2) ms=0.5759 tflops=240.5
cfg=(64, 128, 128, 

... (236 more chars)
assistant
For K=4127, smaller M tiles are much worse; the cost seems tied to odd row stride and the tile shape affects it heavily. I’m letting the search reach the `128x128` and wider-N candidates before deciding whether to add a padding/prepack path.
assistant
write_stdin
args
{
  "session_id": 26164,
  "chars": "",
  "yield_time_ms": 5000,
  "max_output_tokens": 40000
}
tool
stdout (1080 chars)
Chunk ID: 792e02
Wall time: 5.0012 seconds
Process running with session ID 26164
Original token count: 242
Output:
cfg=(64, 128, 256, 4, 4, 2) ms=0.6086 tflops=227.5
cfg=(64, 128, 256, 4, 4, 4) ms=0.6084 tflops=227.6
cfg=(64, 128, 256, 4, 4, 8) ms=0.6084 tflops=227.6
cfg=(64, 128, 256, 4, 5, 2) ms=0.6084 tflops=227.6
cfg=(64, 128, 256, 4, 5, 4) ms=0.6086 tflops=227.5
cfg=(64, 128, 256, 4, 5, 8) ms=0.6076 tflops=227.9
cfg=(64, 128, 256, 8, 3, 2) ms=0.6089 tflops=227.4
cfg=(64, 128, 256, 8, 3, 4) ms=0.6088 tflops=227.5
cfg=(64, 128, 256, 8, 3, 8) ms=0.6095 tflops=227.2
cfg=(64, 128, 256, 8, 4, 2) ms=0.6108 tflops=226.7
cfg=(64, 128, 256, 8, 4, 4) ms=0.6089 tflops=227.4
cfg=(64, 128, 256, 8, 4, 8) ms=0.6090 tflops=227.4
cfg=(64, 128, 256, 8, 5, 2) ms=0.6087 tflops=227.5
cfg=(64, 128, 256, 8, 5, 4) ms=0.6095 tflops=227.2
cfg=(64, 128, 256, 8, 5, 8) ms=0.6092 tflops=227.3
cfg=(64, 256, 64, 4, 3, 2) ms=1.2954 tflops=106.9
cfg=(64, 256, 64, 4, 3, 4) ms=1.2860 tflops=107.7
cfg=(64, 256, 64, 4, 3, 8) ms=1.2826 tflops=108.0
cfg=(64, 256, 64, 4, 4, 2) ms=1.2943 tflops=107.0
assistant
This first sweep was ordered poorly for the off-alignment case and is spending too much time on known-bad `64x*` candidates. I’m stopping it and will run a narrower sweep centered around the current good `128x128x128` path plus a few large-N variants.
assistant
write_stdin
args
{
  "session_id": 26164,
  "chars": "\u0003",
  "yield_time_ms": 1000,
  "max_output_tokens": 20000
}
tool
stdout (105 chars)
write_stdin failed: stdin is closed for this session; rerun exec_command with tty=true to keep stdin open
assistant
exec_command
args
{
  "cmd": "pkill -f \"uv run python -\" || true",
  "workdir": "/workspace/problems/01_fp8_gemm",
  "yield_time_ms": 1000,
  "max_output_tokens": 4000
}
tool
stdout (103 chars)
Chunk ID: 5ff78d
Wall time: 0.0000 seconds
Process exited with code -1
Original token count: 0
Output:
assistant
I killed the overly broad tuning process and will restart with a tighter candidate set. The initial useful takeaway is still valid: aligned shapes like wider-N tiles, but K=4127 needs separate measurement.
assistant
write_stdin
args
{
  "session_id": 26164,
  "chars": "",
  "yield_time_ms": 1000,
  "max_output_tokens": 10000
}
tool
stdout (1060 chars)
Chunk ID: 0743aa
Wall time: 0.0000 seconds
Process exited with code -1
Original token count: 239
Output:
cfg=(64, 256, 64, 4, 4, 4) ms=1.2878 tflops=107.5
cfg=(64, 256, 64, 4, 4, 8) ms=1.2793 tflops=108.2
cfg=(64, 256, 64, 4, 5, 2) ms=1.2948 tflops=106.9
cfg=(64, 256, 64, 4, 5, 4) ms=1.2823 tflops=108.0
cfg=(64, 256, 64, 4, 5, 8) ms=1.2826 tflops=108.0
cfg=(64, 256, 64, 8, 3, 2) ms=0.6565 tflops=210.9
cfg=(64, 256, 64, 8, 3, 4) ms=0.6567 tflops=210.9
cfg=(64, 256, 64, 8, 3, 8) ms=0.6568 tflops=210.8
cfg=(64, 256, 64, 8, 4, 2) ms=0.6578 tflops=210.5
cfg=(64, 256, 64, 8, 4, 4) ms=0.6542 tflops=211.7
cfg=(64, 256, 64, 8, 4, 8) ms=0.6568 tflops=210.8
cfg=(64, 256, 64, 8, 5, 2) ms=0.6546 tflops=211.6
cfg=(64, 256, 64, 8, 5, 4) ms=0.6548 tflops=211.5
cfg=(64, 256, 64, 8, 5, 8) ms=0.6561 tflops=211.1
cfg=(64, 256, 128, 4, 3, 2) ms=0.5953 tflops=232.6
cfg=(64, 256, 128, 4, 3, 4) ms=0.5956 tflops=232.5
cfg=(64, 256, 128, 4, 3, 8) ms=0.5954 tflops=232.6
cfg=(64, 256, 128, 4, 4, 2) ms=0.5948 tflops=232.8
cfg=(64, 256, 128, 4, 4, 4) ms=0.5953 tflops=232.6
assistant
The K=4127 slowdown is probably from the odd row stride causing unaligned row starts for both operands, not just the final tail. I’m checking the timing harness before considering lazy padding/prepacking, because one-time model setup inside warmup may be acceptable but per-call input padding probably will not be.
assistant
exec_command
args
{
  "cmd": "sed -n '1,260p' /workspace/src/eval/timing.py",
  "workdir": "/workspace/problems/01_fp8_gemm",
  "yield_time_ms": 1000,
  "max_output_tokens": 14000
}
assistant
exec_command
args
{
  "cmd": "sed -n '1,220p' /workspace/src/eval/correctness.py",
  "workdir": "/workspace/problems/01_fp8_gemm",
  "yield_time_ms": 1000,
  "max_output_tokens": 12000
}
assistant
exec_command
args
{
  "cmd": "sed -n '1,260p' /workspace/src/eval/numeric_stress.py",
  "workdir": "/workspace/problems/01_fp8_gemm",
  "yield_time_ms": 1000,
  "max_output_tokens": 16000
}
tool
stdout (4419 chars) — TRUNCATED
Chunk ID: 2f79f1
Wall time: 0.0000 seconds
Process exited with code 0
Original token count: 1079
Output:
"""Centralized GPU timing for benchmark.py files.

All problems' benchmark.py should call `time_fn` from here so we have one
implementation of warmup, L2 flush, and CUDA event capture to maintain.

Methodology:
  - 10 warmup calls absorb Triton autotune (typical ~7 configs) and
    torch.compile reduce-overhead CUDA-graph capture.
  - Between each timed call, `_l2_flush()` writes 128 MB to evict L2
    (Blackwell L2 is 96 MB; we want any prior L2 contents flushed so
    we measure HBM-load bandwidth, not L2-cached bandwidth).
  - GPU timing via cuda.Event with synchronize() AFTER record() but
    BEFORE elapsed_time() — the canonical NVIDIA pattern.
  - Reported value is the median of `iters` trials, robust to outliers.

Notes / known biases not addressed here:
  - torch.compile(mode="reduce-overhead") gets CUDA graphs which eliminate
    launch overhead. Custom Triton/CUDA kernels do NOT get this treatment.
    On small shapes where launch overhead matters, this gives compile an
    artificial advantage. We accept this as the cost of using the agreed
    "compiled" baseline policy.
  - cuBLAS / cuDNN allocate workspaces on first call. 10 warmup absorbs.
  - Median over a fairly small number of trials (default 30) is fine for
    headline numbers but won't catch bimodal distributions. Use --extra
    instrumentation if you ever care.
"""
from __future__ import annotations


... (2919 more chars)
tool
stdout (4177 chars) — TRUNCATED
Chunk ID: 57965d
Wall time: 0.0000 seconds
Process exited with code 0
Original token count: 1018
Output:
"""Per-dtype correctness tolerance.

Stanford's KernelBench uses 1e-4 atol/rtol for fp32 and 1e-2 for fp16/bf16.
We extend to fp8 (0.1, permissive) and int (exact).
"""
from __future__ import annotations

import torch

DEFAULT_TOLERANCE = {
    torch.float32: {"atol": 1e-4, "rtol": 1e-4},
    torch.float16: {"atol": 1e-2, "rtol": 1e-2},
    torch.bfloat16: {"atol": 1e-2, "rtol": 1e-2},
    torch.float8_e4m3fn: {"atol": 1e-1, "rtol": 1e-1},
    torch.float8_e5m2: {"atol": 1e-1, "rtol": 1e-1},
    torch.int8: {"atol": 0, "rtol": 0},
    torch.int32: {"atol": 0, "rtol": 0},
    torch.int64: {"atol": 0, "rtol": 0},
}


def _coerce_float(x):
    """Accept int/float/str scientific-notation as float; pass through dicts."""
    if isinstance(x, (int, float)):
        return float(x)
    if isinstance(x, str):
        try:
            return float(x)
        except ValueError:
            return x
    return x


def tolerance_for_dtype(dtype: torch.dtype, override: dict | None = None) -> dict:
    """Lookup atol/rtol for a given dtype, with optional per-problem override.

    The override dict is keyed by str(dtype). Values may be:
      - a single number (or a string parseable as float, e.g. "5e-2") -> used
        as both atol and rtol
      - a dict {"atol": ..., "rtol": ...} -> used directly, with values coerced
    """
    # Accept several spellings of the same dtype key (PyYA

... (2677 more chars)
tool
stdout (6573 chars) — TRUNCATED
Chunk ID: c8721d
Wall time: 0.0000 seconds
Process exited with code 0
Original token count: 1617
Output:
"""Numeric distribution stress cases for correctness checks.

These cases are not hidden shapes. They rerun the same shape/seed validation
under a few scale regimes that catch kernels that only work for the nominal
N(0, 1)-ish inputs.
"""
from __future__ import annotations

import os
from collections.abc import Iterator, Mapping, Sequence
from contextlib import contextmanager
from dataclasses import dataclass, field

import torch

ToleranceOverride = Mapping[str, float | Mapping[str, float]]


@dataclass(frozen=True)
class NumericStressCase:
    name: str
    input_scales: Mapping[int, float] = field(default_factory=dict)
    state_scales: Mapping[str, float] = field(default_factory=dict)
    tolerance: ToleranceOverride | None = None


NOMINAL_CASE = NumericStressCase("nominal")

_SMALL_BF16 = {"bfloat16": {"atol": 1e-4, "rtol": 5e-2}}
_MED_BF16 = {"bfloat16": {"atol": 5e-4, "rtol": 5e-2}}
_LARGE_BF16 = {"bfloat16": {"atol": 2e-1, "rtol": 5e-2}}
_TINY_FP32 = {"float32": {"atol": 1e-7, "rtol": 1e-4}}
_LARGE_FP32 = {"float32": {"atol": 1e-1, "rtol": 1e-4}}

_CASES: dict[str, tuple[NumericStressCase, ...]] = {
    "01_fp8_gemm": (
        # fp8 x fp8 has accumulation-order noise vs the bf16-matmul reference that
        # scales with input magnitude; atols are calibrated to absorb it (measured
        # fp8-MMA residual x ~1.5 margin) while rtol=5e-2 still catches gross erro

... (5073 more chars)
assistant
exec_command
args
{
  "cmd": "<257 chars \u2014 see below>",
  "workdir": "/workspace/problems/01_fp8_gemm",
  "yield_time_ms": 1000,
  "max_output_tokens": 4000
}
cmd (257 chars)
uv run python - <<'PY'
import torch
x=torch.randn(4,5,device='cuda').to(torch.float8_e4m3fn)
y=x.t().contiguous()
print(y.shape, y.dtype, y.is_contiguous())
z=torch.empty((8,4),device='cuda',dtype=torch.float8_e4m3fn)
z.zero_(); z[:5,:].copy_(y)
print(z)
PY
tool
stdout (568 chars)
Chunk ID: 83e43f
Wall time: 0.7484 seconds
Process exited with code 0
Original token count: 116
Output:
torch.Size([5, 4]) torch.float8_e4m3fn True
tensor([[ 1.1250, -0.3125, -0.1875,  1.1250],
        [-0.0938,  0.0625, -0.8750, -0.6250],
        [ 0.1016,  1.0000, -0.5625, -0.2812],
        [-0.7500, -0.8750, -1.7500,  0.4062],
        [-0.6875, -0.8125, -0.3438,  1.0000],
        [ 0.0000,  0.0000,  0.0000,  0.0000],
        [ 0.0000,  0.0000,  0.0000,  0.0000],
        [ 0.0000,  0.0000,  0.0000,  0.0000]], device='cuda:0',
       dtype=torch.float8_e4m3fn)
assistant
I’m adding a second kernel that uses a one-time transposed weight cache, so the B operand is laid out as contiguous `(K, N)` for the tensor-core tile loads. That should help the static weight side and is safe as long as the cache is refreshed when `weight` is modified by the correctness stress cases.
assistant
apply_patch /workspace/problems/01_fp8_gemm/solution.py
diff (96 lines)
--- a//workspace/problems/01_fp8_gemm/solution.py
+++ b//workspace/problems/01_fp8_gemm/solution.py
@@ -1,9 +1,43 @@
+@triton.jit
+def _fp8_gemm_kernel(
+    )
+
+
+@triton.jit
+def _fp8_gemm_wt_kernel(
+    x_ptr,
+    wt_ptr,
+    scale_ptr,
+    y_ptr,
+    M: tl.constexpr,
+    N: tl.constexpr,
+    K: tl.constexpr,
+    BLOCK_M: tl.constexpr,
+    BLOCK_N: tl.constexpr,
+    BLOCK_K: tl.constexpr,
+    GROUP_M: tl.constexpr,
+):
+    pid = tl.program_id(0)
+    num_pid_m = tl.cdiv(M, BLOCK_M)
+    num_pid_n = tl.cdiv(N, BLOCK_N)
+    group_size = GROUP_M * num_pid_n
+    group_id = pid // group_size
+    first_pid_m = group_id * GROUP_M
+    group_m = tl.minimum(num_pid_m - first_pid_m, GROUP_M)
+    pid_in_group = pid - group_id * group_size
+    pid_m = first_pid_m + (pid_in_group % group_m)
+    pid_n = pid_in_group // group_m
+
+    offs_m = pid_m * BLOCK_M + tl.arange(0, BLOCK_M)
+    offs_n = pid_n * BLOCK_N + tl.arange(0, BLOCK_N)
+    offs_k = tl.arange(0, BLOCK_K)
+
     acc = tl.zeros((BLOCK_M, BLOCK_N), tl.float32)
     full_k = (K // BLOCK_K) * BLOCK_K
     for k0 in range(0, full_k, BLOCK_K):
         k = k0 + offs_k
         a = tl.load(x_ptr + offs_m[:, None] * K + k[None, :])
-        b = tl.load(w_ptr + offs_n[None, :] * K + k[:, None])
+        b = tl.load(wt_ptr + k[:, None] * N + offs_n[None, :])
         acc = tl.dot(a, b, acc, out_dtype=tl.float32)
 
     if full_k < K:
@@ -14,9 +48,47 @@
             other=0.0,
         )
         b = tl.load(
-            w_ptr + offs_n[None, :] * K + k[:, None],
+            wt_ptr + k[:, None] * N + offs_n[None, :],
             mask=k[:, None] < K,
             other=0.0,
         )
         acc = tl.dot(a, b, acc, out_dtype=tl.float32)
 
+    scales = tl.load(scale_ptr + offs_n, mask=offs_n < N, other=0.0)
+    acc = acc * scales[None, :]
+    tl.store(
+        y_ptr + offs_m[:, None] * N + offs_n[None, :],
+        acc,
+        mask=(offs_m[:, None] < M) & (offs_n[None, :] < N),
+    )
+
+
+def _launch_fp8_gemm(x: torch.Tensor, weight_t: torch.Tensor, weight_scale: torch.Tensor, M: int, N: int, K: int):
+    y = torch.empty((M, N), device=x.device, dtype=torch.bfloat16)
+
+    if M <= 64:
+        bm, bn, bk = 32, 128, 128
+        warps, stages, group_m = 4, 4, 4
+    grid = (triton.cdiv(M, bm) * triton.cdiv(N, bn),)
+    _fp8_gemm_wt_kernel[grid](
+        x,
+        weight_t,
+        weight_scale,
+        y,
+        M,
+        self.M, self.N, self.K = M, N, K
+        self._weight_t = None
+        self._weight_t_key = None
+        w = torch.empty(N, K, dtype=torch.bfloat16)
+    def forward(self, x: torch.Tensor) -> torch.Tensor:
+        if not x.is_cuda:
+            x_bf = x.to(torch.bfloat16)
+            w_bf = self.weight.to(torch.bfloat16)
+            y = (x_bf @ w_bf.T).float()
+            y = y * self.weight_scale[None, :]
+            return y.to(torch.bfloat16)
+        key = (self.weight.data_ptr(), self.weight._version, self.weight.device, self.weight.shape)
+        if self._weight_t is None or self._weight_t_key != key:
+            self._weight_t = self.weight.t().contiguous()
+            self._weight_t_key = key
+        return _launch_fp8_gemm(x, self._weight_t, self.weight_scale, self.M, self.N, self.K)
args
{
  "raw": "<3507 chars \u2014 see below>"
}
raw (3507 chars)
*** Begin Patch
*** Update File: /workspace/problems/01_fp8_gemm/solution.py
@@
 @triton.jit
 def _fp8_gemm_kernel(
@@
     )
 
 
-def _launch_fp8_gemm(x: torch.Tensor, weight: torch.Tensor, weight_scale: torch.Tensor, M: int, N: int, K: int):
+@triton.jit
+def _fp8_gemm_wt_kernel(
+    x_ptr,
+    wt_ptr,
+    scale_ptr,
+    y_ptr,
+    M: tl.constexpr,
+    N: tl.constexpr,
+    K: tl.constexpr,
+    BLOCK_M: tl.constexpr,
+    BLOCK_N: tl.constexpr,
+    BLOCK_K: tl.constexpr,
+    GROUP_M: tl.constexpr,
+):
+    pid = tl.program_id(0)
+    num_pid_m = tl.cdiv(M, BLOCK_M)
+    num_pid_n = tl.cdiv(N, BLOCK_N)
+    group_size = GROUP_M * num_pid_n
+    group_id = pid // group_size
+    first_pid_m = group_id * GROUP_M
+    group_m = tl.minimum(num_pid_m - first_pid_m, GROUP_M)
+    pid_in_group = pid - group_id * group_size
+    pid_m = first_pid_m + (pid_in_group % group_m)
+    pid_n = pid_in_group // group_m
+
+    offs_m = pid_m * BLOCK_M + tl.arange(0, BLOCK_M)
+    offs_n = pid_n * BLOCK_N + tl.arange(0, BLOCK_N)
+    offs_k = tl.arange(0, BLOCK_K)
+
+    acc = tl.zeros((BLOCK_M, BLOCK_N), tl.float32)
+    full_k = (K // BLOCK_K) * BLOCK_K
+    for k0 in range(0, full_k, BLOCK_K):
+        k = k0 + offs_k
+        a = tl.load(x_ptr + offs_m[:, None] * K + k[None, :])
+        b = tl.load(wt_ptr + k[:, None] * N + offs_n[None, :])
+        acc = tl.dot(a, b, acc, out_dtype=tl.float32)
+
+    if full_k < K:
+        k = full_k + offs_k
+        a = tl.load(
+            x_ptr + offs_m[:, None] * K + k[None, :],
+            mask=k[None, :] < K,
+            other=0.0,
+        )
+        b = tl.load(
+            wt_ptr + k[:, None] * N + offs_n[None, :],
+            mask=k[:, None] < K,
+            other=0.0,
+        )
+        acc = tl.dot(a, b, acc, out_dtype=tl.float32)
+
+    scales = tl.load(scale_ptr + offs_n, mask=offs_n < N, other=0.0)
+    acc = acc * scales[None, :]
+    tl.store(
+        y_ptr + offs_m[:, None] * N + offs_n[None, :],
+        acc,
+        mask=(offs_m[:, None] < M) & (offs_n[None, :] < N),
+    )
+
+
+def _launch_fp8_gemm(x: torch.Tensor, weight_t: torch.Tensor, weight_scale: torch.Tensor, M: int, N: int, K: int):
     y = torch.empty((M, N), device=x.device, dtype=torch.bfloat16)
 
     if M <= 64:
         bm, bn, bk = 32, 128, 128
         warps, stages, group_m = 4, 4, 4
@@
     grid = (triton.cdiv(M, bm) * triton.cdiv(N, bn),)
-    _fp8_gemm_kernel[grid](
+    _fp8_gemm_wt_kernel[grid](
         x,
-        weight,
+        weight_t,
         weight_scale,
         y,
         M,
@@
         self.M, self.N, self.K = M, N, K
+        self._weight_t = None
+        self._weight_t_key = None
         w = torch.empty(N, K, dtype=torch.bfloat16)
@@
     def forward(self, x: torch.Tensor) -> torch.Tensor:
         if not x.is_cuda:
             x_bf = x.to(torch.bfloat16)
             w_bf = self.weight.to(torch.bfloat16)
             y = (x_bf @ w_bf.T).float()
             y = y * self.weight_scale[None, :]
             return y.to(torch.bfloat16)
-        return _launch_fp8_gemm(x, self.weight, self.weight_scale, self.M, self.N, self.K)
+        key = (self.weight.data_ptr(), self.weight._version, self.weight.device, self.weight.shape)
+        if self._weight_t is None or self._weight_t_key != key:
+            self._weight_t = self.weight.t().contiguous()
+            self._weight_t_key = key
+        return _launch_fp8_gemm(x, self._weight_t, self.weight_scale, self.M, self.N, self.K)
*** End Patch
tool
stdout (144 chars)
output:
  Success. Updated the following files:
  M /workspace/problems/01_fp8_gemm/solution.py
metadata:
  exit_code: 0
  duration_seconds: 0.0
assistant
The transposed-weight path is wired into `Model.forward` with a `_version`-based cache key. I’m running the full checker again because the numeric stress harness mutates buffers and will catch stale cache handling.
assistant
exec_command
args
{
  "cmd": "uv run python check.py",
  "workdir": "/workspace/problems/01_fp8_gemm",
  "yield_time_ms": 1000,
  "max_output_tokens": 20000
}
tool
stdout (113 chars)
Chunk ID: e4f34d
Wall time: 1.0005 seconds
Process running with session ID 97053
Original token count: 0
Output:
assistant
write_stdin
args
{
  "session_id": 97053,
  "chars": "",
  "yield_time_ms": 1000,
  "max_output_tokens": 20000
}
tool
stdout (107 chars)
Chunk ID: 8e401d
Wall time: 4.4972 seconds
Process exited with code 0
Original token count: 2
Output:
PASS
assistant
Correctness still passes with the cache. Now I’m benchmarking it; if the transpose layout improves B-side loads, it should show up on all large-N shapes, not just the K-tail case.
assistant
exec_command
args
{
  "cmd": "uv run python benchmark.py",
  "workdir": "/workspace/problems/01_fp8_gemm",
  "yield_time_ms": 1000,
  "max_output_tokens": 20000
}
tool
stdout (211 chars)
Chunk ID: 2ec068
Wall time: 1.0012 seconds
Process running with session ID 97847
Original token count: 25
Output:
benchmark_event event=variant_start shape=0 variant=solution ts=2026-06-14T20:48:28.655946+00:00
assistant
write_stdin
args
{
  "session_id": 97847,
  "chars": "",
  "yield_time_ms": 1000,
  "max_output_tokens": 20000
}
tool
stdout (1319 chars)
Chunk ID: 3177d3
Wall time: 2.7995 seconds
Process exited with code 0
Original token count: 304
Output:
benchmark_event event=variant_end shape=0 variant=solution ts=2026-06-14T20:48:28.871534+00:00 elapsed_s=0.216 ms=0.290912
shape=0 variant=solution tflops=472.442 gbps=230.684 ms=0.291
shape=0 solution_peak_fraction=0.4724
benchmark_event event=variant_start shape=1 variant=solution ts=2026-06-14T20:48:29.390259+00:00
benchmark_event event=variant_end shape=1 variant=solution ts=2026-06-14T20:48:29.414727+00:00 elapsed_s=0.024 ms=0.530864
shape=1 variant=solution tflops=260.856 gbps=126.893 ms=0.531
shape=1 solution_peak_fraction=0.2609
benchmark_event event=variant_start shape=2 variant=solution ts=2026-06-14T20:48:31.259349+00:00
benchmark_event event=variant_end shape=2 variant=solution ts=2026-06-14T20:48:31.265718+00:00 elapsed_s=0.006 ms=0.078432
shape=2 variant=solution tflops=54.760 gbps=865.658 ms=0.078
shape=2 solution_peak_fraction=0.0548
benchmark_event event=variant_start shape=3 variant=solution ts=2026-06-14T20:48:32.937228+00:00
benchmark_event event=variant_end shape=3 variant=solution ts=2026-06-14T20:48:32.977645+00:00 elapsed_s=0.040 ms=0.923184
shape=3 variant=solution tflops=521.062 gbps=208.992 ms=0.923
shape=3 solution_peak_fraction=0.5211
peak_fraction: 0.2435
RESULT: OK
assistant
The transposed weight cache is slower across the board, so I won’t keep it in the final launch path. I’m switching back to the original row-major weight kernel and narrowing the tile search around the candidates that actually helped.
assistant
exec_command
args
{
  "cmd": "<2084 chars \u2014 see below>",
  "workdir": "/workspace/problems/01_fp8_gemm",
  "yield_time_ms": 1000,
  "max_output_tokens": 50000
}
cmd (2084 chars)
uv run python - <<'PY'
import itertools, statistics
import torch, triton
import reference, solution, shapes
from src.eval.timing import time_fn
from src.eval.roofline import compute_tflops

device='cuda'

def bench(shape_idx, configs):
    shape=shapes.SHAPES[shape_idx]
    M,N,K=shape['M'],shape['N'],shape['K']
    reference.M, reference.N, reference.K = M,N,K
    ref=reference.Model(M,N,K).to(device).eval()
    x=reference.get_inputs()[0].to(device)
    print('\nshape', shape_idx, shape, flush=True)
    best=[]
    for bm,bn,bk,warps,stages,gm in configs:
        if M % bm or N % bn: continue
        y=torch.empty((M,N),device=device,dtype=torch.bfloat16)
        grid=(triton.cdiv(M,bm)*triton.cdiv(N,bn),)
        def fn():
            solution._fp8_gemm_kernel[grid](x,ref.weight,ref.weight_scale,y,M,N,K,BLOCK_M=bm,BLOCK_N=bn,BLOCK_K=bk,GROUP_M=gm,num_warps=warps,num_stages=stages)
            return y
        try:
            ms=time_fn(lambda: fn(), [], iters=10, warmup=4)
            tf=compute_tflops(2*M*N*K, ms)
            best.append((ms,tf,(bm,bn,bk,warps,stages,gm)))
            print(f'{(bm,bn,bk,warps,stages,gm)} ms={ms:.4f} tf={tf:.1f}', flush=True)
        except Exception as e:
            print(f'{(bm,bn,bk,warps,stages,gm)} ERR {type(e).__name__}: {e}', flush=True)
            torch.cuda.synchronize()
    best.sort()
    print('BEST', flush=True)
    for row in best[:10]:
        print(f'  {row[2]} ms={row[0]:.4f} tf={row[1]:.1f}', flush=True)

large_configs=[]
for bm,bn,bk in [(128,128,128),(128,128,64),(128,128,256),(64,256,64),(64,256,128),(128,256,64),(256,128,64),(128,64,64),(256,64,64)]:
  for warps in [4,8]:
    for stages in [3,4]:
      for gm in [2,4,8]:
        large_configs.append((bm,bn,bk,warps,stages,gm))
bench(0, large_configs)
bench(1, large_configs)
bench(3, large_configs)

skinny=[]
for bn,bk in [(64,64),(64,128),(128,64),(128,128),(256,64),(256,128),(512,64),(512,128)]:
  for warps in [4,8]:
    for stages in [3,4]:
      for gm in [1,2,4,8]:
        skinny.append((32,bn,bk,warps,stages,gm))
bench(2, skinny)
PY
tool
stdout (113 chars)
Chunk ID: 9905ad
Wall time: 1.0011 seconds
Process running with session ID 52362
Original token count: 0
Output:
assistant
write_stdin
args
{
  "session_id": 52362,
  "chars": "",
  "yield_time_ms": 5000,
  "max_output_tokens": 50000
}
tool
stdout (2364 chars) — TRUNCATED
Chunk ID: 7d4850
Wall time: 5.0019 seconds
Process running with session ID 52362
Original token count: 563
Output:

shape 0 {'M': 4096, 'N': 4096, 'K': 4096}
(128, 128, 128, 4, 3, 2) ms=0.2306 tf=596.1
(128, 128, 128, 4, 3, 4) ms=0.2268 tf=605.9
(128, 128, 128, 4, 3, 8) ms=0.2278 tf=603.3
(128, 128, 128, 4, 4, 2) ms=0.2283 tf=602.1
(128, 128, 128, 4, 4, 4) ms=0.2287 tf=601.1
(128, 128, 128, 4, 4, 8) ms=0.2290 tf=600.3
(128, 128, 128, 8, 3, 2) ms=0.2326 tf=590.9
(128, 128, 128, 8, 3, 4) ms=0.2316 tf=593.3
(128, 128, 128, 8, 3, 8) ms=0.2311 tf=594.6
(128, 128, 128, 8, 4, 2) ms=0.2337 tf=588.2
(128, 128, 128, 8, 4, 4) ms=0.2329 tf=590.0
(128, 128, 128, 8, 4, 8) ms=0.2329 tf=590.2
(128, 128, 64, 4, 3, 2) ms=0.2235 tf=614.9
(128, 128, 64, 4, 3, 4) ms=0.2225 tf=617.6
(128, 128, 64, 4, 3, 8) ms=0.2241 tf=613.3
(128, 128, 64, 4, 4, 2) ms=0.2253 tf=610.1
(128, 128, 64, 4, 4, 4) ms=0.2254 tf=609.7
(128, 128, 64, 4, 4, 8) ms=0.2250 tf=610.7
(128, 128, 64, 8, 3, 2) ms=0.2306 tf=596.0
(128, 128, 64, 8, 3, 4) ms=0.2293 tf=599.4
(128, 128, 64, 8, 3, 8) ms=0.2293 tf=599.4
(128, 128, 64, 8, 4, 2) ms=0.2312 tf=594.5
(128, 128, 64, 8, 4, 4) ms=0.2306 tf=595.9
(128, 128, 64, 8, 4, 8) ms=0.2311 tf=594.7
(128, 128, 256, 4, 3, 2) ERR OutOfResources: out of resource: shared memory, Required: 131072, Hardware limit: 101376. Reducing block sizes or `num_stages` may help.
(128, 128, 256, 4, 3, 4) ERR OutOfResources: out of resource: shared memory, Required: 131072, Hardware limit: 101376. Reducing bloc

... (864 more chars)
assistant
write_stdin
args
{
  "session_id": 52362,
  "chars": "",
  "yield_time_ms": 5000,
  "max_output_tokens": 50000
}
tool
stdout (4023 chars) — TRUNCATED
Chunk ID: e88166
Wall time: 5.0005 seconds
Process running with session ID 52362
Original token count: 977
Output:
(128, 128, 256, 8, 3, 4) ERR OutOfResources: out of resource: shared memory, Required: 131072, Hardware limit: 101376. Reducing block sizes or `num_stages` may help.
(128, 128, 256, 8, 3, 8) ERR OutOfResources: out of resource: shared memory, Required: 131072, Hardware limit: 101376. Reducing block sizes or `num_stages` may help.
(128, 128, 256, 8, 4, 2) ERR OutOfResources: out of resource: shared memory, Required: 196608, Hardware limit: 101376. Reducing block sizes or `num_stages` may help.
(128, 128, 256, 8, 4, 4) ERR OutOfResources: out of resource: shared memory, Required: 196608, Hardware limit: 101376. Reducing block sizes or `num_stages` may help.
(128, 128, 256, 8, 4, 8) ERR OutOfResources: out of resource: shared memory, Required: 196608, Hardware limit: 101376. Reducing block sizes or `num_stages` may help.
(64, 256, 64, 4, 3, 2) ms=0.2367 tf=580.8
(64, 256, 64, 4, 3, 4) ms=0.2367 tf=580.6
(64, 256, 64, 4, 3, 8) ms=0.2375 tf=578.6
(64, 256, 64, 4, 4, 2) ms=0.2515 tf=546.6
(64, 256, 64, 4, 4, 4) ms=0.2530 tf=543.2
(64, 256, 64, 4, 4, 8) ms=0.2519 tf=545.6
(64, 256, 64, 8, 3, 2) ms=0.2418 tf=568.4
(64, 256, 64, 8, 3, 4) ms=0.2416 tf=568.9
(64, 256, 64, 8, 3, 8) ms=0.2417 tf=568.7
(64, 256, 64, 8, 4, 2) ms=0.2565 tf=535.8
(64, 256, 64, 8, 4, 4) ms=0.2581 tf=532.5
(64, 256, 64, 8, 4, 8) ms=0.2591 tf=530.4
(64, 256, 128, 4, 3, 2) ms=0.2419 tf=568.1
(64, 256

... (2523 more chars)
assistant
With the real L2-flushing timer, the aligned shape’s best candidate is around `256x128x64` or `128x256x64` with 8 warps, about 0.216 ms. That is a real improvement over the current 0.234 ms, so I’ll use a large-tile 8-warp config for aligned large GEMMs if it doesn’t hurt shape 3.
assistant
write_stdin
args
{
  "session_id": 52362,
  "chars": "",
  "yield_time_ms": 5000,
  "max_output_tokens": 50000
}
tool
stdout (2365 chars) — TRUNCATED
Chunk ID: b4376d
Wall time: 5.0007 seconds
Process running with session ID 52362
Original token count: 563
Output:
(128, 64, 64, 8, 3, 4) ms=0.2608 tf=526.9
(128, 64, 64, 8, 3, 8) ms=0.2591 tf=530.4
(128, 64, 64, 8, 4, 2) ms=0.2671 tf=514.6
(128, 64, 64, 8, 4, 4) ms=0.2637 tf=521.2
(128, 64, 64, 8, 4, 8) ms=0.2614 tf=525.8
(256, 64, 64, 4, 3, 2) ms=0.2413 tf=569.5
(256, 64, 64, 4, 3, 4) ms=0.2372 tf=579.4
(256, 64, 64, 4, 3, 8) ms=0.2350 tf=584.9
(256, 64, 64, 4, 4, 2) ms=0.2543 tf=540.6
(256, 64, 64, 4, 4, 4) ms=0.2515 tf=546.5
(256, 64, 64, 4, 4, 8) ms=0.2475 tf=555.3
(256, 64, 64, 8, 3, 2) ms=0.2454 tf=560.0
(256, 64, 64, 8, 3, 4) ms=0.2442 tf=562.9
(256, 64, 64, 8, 3, 8) ms=0.2436 tf=564.3
(256, 64, 64, 8, 4, 2) ms=0.2593 tf=529.9
(256, 64, 64, 8, 4, 4) ms=0.2573 tf=534.1
(256, 64, 64, 8, 4, 8) ms=0.2536 tf=541.8
BEST
  (256, 128, 64, 8, 4, 4) ms=0.2161 tf=636.0
  (256, 128, 64, 8, 4, 8) ms=0.2162 tf=635.7
  (256, 128, 64, 8, 3, 8) ms=0.2163 tf=635.5
  (256, 128, 64, 8, 3, 4) ms=0.2167 tf=634.1
  (128, 256, 64, 8, 4, 2) ms=0.2171 tf=633.0
  (256, 128, 64, 8, 4, 2) ms=0.2173 tf=632.4
  (256, 128, 64, 8, 3, 2) ms=0.2186 tf=628.8
  (128, 256, 64, 8, 4, 4) ms=0.2186 tf=628.7
  (128, 256, 64, 8, 4, 8) ms=0.2186 tf=628.7
  (128, 256, 64, 8, 3, 8) ms=0.2193 tf=626.6

shape 1 {'M': 4096, 'N': 4096, 'K': 4127}
(128, 128, 128, 4, 3, 2) ms=0.4297 tf=322.3
(128, 128, 128, 4, 3, 4) ms=0.4241 tf=326.5
(128, 128, 128, 4, 3, 8) ms=0.4236 tf=326.9
(128, 128, 128, 4, 4, 2) ms=0.4283 tf=323

... (865 more chars)
assistant
write_stdin
args
{
  "session_id": 52362,
  "chars": "",
  "yield_time_ms": 5000,
  "max_output_tokens": 50000
}
tool
stdout (641 chars)
Chunk ID: 766008
Wall time: 5.0013 seconds
Process running with session ID 52362
Original token count: 132
Output:
(128, 128, 256, 4, 3, 2) ms=1.4029 tf=98.7
(128, 128, 256, 4, 3, 4) ms=1.2040 tf=115.0
(128, 128, 256, 4, 3, 8) ms=1.1446 tf=121.0
(128, 128, 256, 4, 4, 2) ms=1.4043 tf=98.6
(128, 128, 256, 4, 4, 4) ms=1.2080 tf=114.6
(128, 128, 256, 4, 4, 8) ms=1.1435 tf=121.1
(128, 128, 256, 8, 3, 2) ms=0.8289 tf=167.1
(128, 128, 256, 8, 3, 4) ms=0.8290 tf=167.0
(128, 128, 256, 8, 3, 8) ms=0.8332 tf=166.2
(128, 128, 256, 8, 4, 2) ms=0.8292 tf=167.0
(128, 128, 256, 8, 4, 4) ms=0.8332 tf=166.2
(128, 128, 256, 8, 4, 8) ms=0.8303 tf=166.8
assistant
For K=4127, the only good family so far is the original `128x128x128` with 4 warps; `BLOCK_K=64` and `256` are much slower for odd K. I’ll keep that shape on the 128-K tile unless a later large-M/N variant beats it.
assistant
write_stdin
args
{
  "session_id": 52362,
  "chars": "",
  "yield_time_ms": 5000,
  "max_output_tokens": 50000
}
tool
stdout (1339 chars)
Chunk ID: 0985ca
Wall time: 5.0009 seconds
Process running with session ID 52362
Original token count: 306
Output:
(64, 256, 64, 4, 3, 2) ms=1.3905 tf=99.6
(64, 256, 64, 4, 3, 4) ms=1.4196 tf=97.5
(64, 256, 64, 4, 3, 8) ms=1.3997 tf=98.9
(64, 256, 64, 4, 4, 2) ms=1.3912 tf=99.5
(64, 256, 64, 4, 4, 4) ms=1.4160 tf=97.8
(64, 256, 64, 4, 4, 8) ms=1.4008 tf=98.9
(64, 256, 64, 8, 3, 2) ms=0.7721 tf=179.3
(64, 256, 64, 8, 3, 4) ms=0.7719 tf=179.4
(64, 256, 64, 8, 3, 8) ms=0.7408 tf=186.9
(64, 256, 64, 8, 4, 2) ms=0.7758 tf=178.5
(64, 256, 64, 8, 4, 4) ms=0.7737 tf=179.0
(64, 256, 64, 8, 4, 8) ms=0.7430 tf=186.4
(64, 256, 128, 4, 3, 2) ms=0.6293 tf=220.1
(64, 256, 128, 4, 3, 4) ms=0.6302 tf=219.7
(64, 256, 128, 4, 3, 8) ms=0.6289 tf=220.2
(64, 256, 128, 4, 4, 2) ms=0.6318 tf=219.2
(64, 256, 128, 4, 4, 4) ms=0.6302 tf=219.7
(64, 256, 128, 4, 4, 8) ms=0.6288 tf=220.2
(64, 256, 128, 8, 3, 2) ms=1.3659 tf=101.4
(64, 256, 128, 8, 3, 4) ms=1.3684 tf=101.2
(64, 256, 128, 8, 3, 8) ms=1.3834 tf=100.1
(64, 256, 128, 8, 4, 2) ms=1.3676 tf=101.3
(64, 256, 128, 8, 4, 4) ms=1.3707 tf=101.0
(64, 256, 128, 8, 4, 8) ms=1.3808 tf=100.3
(128, 256, 64, 4, 3, 2) ms=19.0026 tf=7.3
(128, 256, 64, 4, 3, 4) ms=19.0256 tf=7.3
(128, 256, 64, 4, 3, 8) ms=19.0928 tf=7.3
(128, 256, 64, 4, 4, 2) ms=19.0246 tf=7.3
(128, 256, 64, 4, 4, 4) ms=19.0734 tf=7.3
assistant
A few odd-K large-N candidates are catastrophically slow, so I’m stopping this sweep before it wastes time. We have enough to choose the odd-K tile: `128x128x128`, 4 warps, stage 3/4, grouped by 8.
assistant
exec_command
args
{
  "cmd": "pkill -f \"uv run python -\" || true",
  "workdir": "/workspace/problems/01_fp8_gemm",
  "yield_time_ms": 1000,
  "max_output_tokens": 4000
}
tool
stdout (103 chars)
Chunk ID: 8810a4
Wall time: 0.0000 seconds
Process exited with code -1
Original token count: 0
Output:
assistant
Next I’ll make the wrapper shape-select: aligned large GEMMs get the `256x128x64` style tile, K=4127 stays on `128x128x128`, and skinny-M still needs a small dedicated sweep.
assistant
write_stdin
args
{
  "session_id": 52362,
  "chars": "",
  "yield_time_ms": 1000,
  "max_output_tokens": 10000
}
tool
stdout (531 chars)
Chunk ID: 02468a
Wall time: 0.0000 seconds
Process exited with code -1
Original token count: 107
Output:
(128, 256, 64, 4, 4, 8) ms=19.0909 tf=7.3
(128, 256, 64, 8, 3, 2) ms=0.9149 tf=151.4
(128, 256, 64, 8, 3, 4) ms=0.9193 tf=150.6
(128, 256, 64, 8, 3, 8) ms=0.9136 tf=151.6
(128, 256, 64, 8, 4, 2) ms=0.9152 tf=151.3
(128, 256, 64, 8, 4, 4) ms=0.9201 tf=150.5
(128, 256, 64, 8, 4, 8) ms=0.9128 tf=151.7
(256, 128, 64, 4, 3, 2) ms=21.3403 tf=6.5
(256, 128, 64, 4, 3, 4) ms=21.3595 tf=6.5
(256, 128, 64, 4, 3, 8) ms=21.3588 tf=6.5
assistant
I’m doing a short shape-3-only timing run now, using just the viable aligned configs. This avoids the odd-K bad cases and should tell us whether the square-shape winner also helps the Llama up-proj shape.
assistant
exec_command
args
{
  "cmd": "<1539 chars \u2014 see below>",
  "workdir": "/workspace/problems/01_fp8_gemm",
  "yield_time_ms": 1000,
  "max_output_tokens": 20000
}
cmd (1539 chars)
uv run python - <<'PY'
import torch, triton
import reference, solution, shapes
from src.eval.timing import time_fn
from src.eval.roofline import compute_tflops

device='cuda'
shape=shapes.SHAPES[3]
M,N,K=shape['M'],shape['N'],shape['K']
reference.M,reference.N,reference.K=M,N,K
ref=reference.Model(M,N,K).to(device).eval()
x=reference.get_inputs()[0].to(device)
configs=[]
for cfg in [
 (128,128,128,4,3,4),(128,128,128,4,3,8),(128,128,128,4,4,4),
 (128,128,64,4,3,4),(128,128,64,4,3,8),
 (256,128,64,8,4,4),(256,128,64,8,3,8),(128,256,64,8,4,2),(128,256,64,8,3,8),
 (64,256,64,4,3,8),(64,256,128,4,3,4),
 (256,64,64,4,3,8),(256,64,64,8,3,8),
]:
    configs.append(cfg)
print('shape', shape, flush=True)
best=[]
for bm,bn,bk,warps,stages,gm in configs:
    y=torch.empty((M,N),device=device,dtype=torch.bfloat16)
    grid=(triton.cdiv(M,bm)*triton.cdiv(N,bn),)
    def fn():
        solution._fp8_gemm_kernel[grid](x,ref.weight,ref.weight_scale,y,M,N,K,BLOCK_M=bm,BLOCK_N=bn,BLOCK_K=bk,GROUP_M=gm,num_warps=warps,num_stages=stages)
        return y
    try:
        ms=time_fn(lambda: fn(), [], iters=12, warmup=4)
        tf=compute_tflops(2*M*N*K, ms)
        best.append((ms,tf,(bm,bn,bk,warps,stages,gm)))
        print(f'{(bm,bn,bk,warps,stages,gm)} ms={ms:.4f} tf={tf:.1f}', flush=True)
    except Exception as e:
        print(f'{(bm,bn,bk,warps,stages,gm)} ERR {type(e).__name__}: {e}', flush=True)
        torch.cuda.synchronize()
best.sort()
print('BEST')
for ms,tf,cfg in best:
    print(cfg, f'ms={ms:.4f}', f'tf={tf:.1f}')
PY
tool
stdout (113 chars)
Chunk ID: c38d7e
Wall time: 1.0013 seconds
Process running with session ID 91423
Original token count: 0
Output:
assistant
write_stdin
args
{
  "session_id": 91423,
  "chars": "",
  "yield_time_ms": 5000,
  "max_output_tokens": 20000
}
tool
stdout (1268 chars)
Chunk ID: ea7ad8
Wall time: 0.6415 seconds
Process exited with code 0
Original token count: 291
Output:
shape {'M': 4096, 'N': 14336, 'K': 4096}
(128, 128, 128, 4, 3, 4) ms=0.7334 tf=655.9
(128, 128, 128, 4, 3, 8) ms=0.7353 tf=654.2
(128, 128, 128, 4, 4, 4) ms=0.7321 tf=657.1
(128, 128, 64, 4, 3, 4) ms=0.7248 tf=663.7
(128, 128, 64, 4, 3, 8) ms=0.7220 tf=666.3
(256, 128, 64, 8, 4, 4) ms=0.7033 tf=684.0
(256, 128, 64, 8, 3, 8) ms=0.7138 tf=673.9
(128, 256, 64, 8, 4, 2) ms=0.7012 tf=686.0
(128, 256, 64, 8, 3, 8) ms=0.7055 tf=681.9
(64, 256, 64, 4, 3, 8) ms=0.7792 tf=617.3
(64, 256, 128, 4, 3, 4) ms=0.7820 tf=615.2
(256, 64, 64, 4, 3, 8) ms=0.7816 tf=615.4
(256, 64, 64, 8, 3, 8) ms=0.8076 tf=595.6
BEST
(128, 256, 64, 8, 4, 2) ms=0.7012 tf=686.0
(256, 128, 64, 8, 4, 4) ms=0.7033 tf=684.0
(128, 256, 64, 8, 3, 8) ms=0.7055 tf=681.9
(256, 128, 64, 8, 3, 8) ms=0.7138 tf=673.9
(128, 128, 64, 4, 3, 8) ms=0.7220 tf=666.3
(128, 128, 64, 4, 3, 4) ms=0.7248 tf=663.7
(128, 128, 128, 4, 4, 4) ms=0.7321 tf=657.1
(128, 128, 128, 4, 3, 4) ms=0.7334 tf=655.9
(128, 128, 128, 4, 3, 8) ms=0.7353 tf=654.2
(64, 256, 64, 4, 3, 8) ms=0.7792 tf=617.3
(256, 64, 64, 4, 3, 8) ms=0.7816 tf=615.4
(64, 256, 128, 4, 3, 4) ms=0.7820 tf=615.2
(256, 64, 64, 8, 3, 8) ms=0.8076 tf=595.6
assistant
Shape 3 benefits from the same broader-N/K64 family, with `128x256x64` narrowly best. I’m timing skinny-M candidates now; that one is memory-bound, so the best tile may be very different.
assistant
exec_command
args
{
  "cmd": "<1581 chars \u2014 see below>",
  "workdir": "/workspace/problems/01_fp8_gemm",
  "yield_time_ms": 1000,
  "max_output_tokens": 50000
}
cmd (1581 chars)
uv run python - <<'PY'
import torch, triton
import reference, solution, shapes
from src.eval.timing import time_fn
from src.eval.roofline import compute_tflops, compute_gbps

device='cuda'
shape=shapes.SHAPES[2]
M,N,K=shape['M'],shape['N'],shape['K']
reference.M,reference.N,reference.K=M,N,K
ref=reference.Model(M,N,K).to(device).eval()
x=reference.get_inputs()[0].to(device)
configs=[]
for bn in [32,64,128,256,512,1024]:
  for bk in [64,128,256]:
    for warps in [4,8]:
      for stages in [3,4]:
        for gm in [1,2,4,8]:
          configs.append((32,bn,bk,warps,stages,gm))
print('shape', shape, flush=True)
best=[]
bytes_moved=M*K+K*N+M*N*2
for bm,bn,bk,warps,stages,gm in configs:
    if N % bn: continue
    y=torch.empty((M,N),device=device,dtype=torch.bfloat16)
    grid=(triton.cdiv(M,bm)*triton.cdiv(N,bn),)
    def fn():
        solution._fp8_gemm_kernel[grid](x,ref.weight,ref.weight_scale,y,M,N,K,BLOCK_M=bm,BLOCK_N=bn,BLOCK_K=bk,GROUP_M=gm,num_warps=warps,num_stages=stages)
        return y
    try:
        ms=time_fn(lambda: fn(), [], iters=12, warmup=4)
        tf=compute_tflops(2*M*N*K, ms)
        gb=compute_gbps(bytes_moved, ms)
        best.append((ms,tf,gb,(bm,bn,bk,warps,stages,gm)))
        print(f'{(bm,bn,bk,warps,stages,gm)} ms={ms:.4f} tf={tf:.1f} gb={gb:.0f}', flush=True)
    except Exception as e:
        print(f'{(bm,bn,bk,warps,stages,gm)} ERR {type(e).__name__}: {e}', flush=True)
        torch.cuda.synchronize()
best.sort()
print('BEST')
for ms,tf,gb,cfg in best[:16]:
    print(cfg, f'ms={ms:.4f}', f'tf={tf:.1f}', f'gb={gb:.0f}')
PY
tool
stdout (113 chars)
Chunk ID: 7849f5
Wall time: 1.0010 seconds
Process running with session ID 74526
Original token count: 0
Output:
assistant
write_stdin
args
{
  "session_id": 74526,
  "chars": "",
  "yield_time_ms": 5000,
  "max_output_tokens": 50000
}
tool
stdout (8372 chars) — TRUNCATED
Chunk ID: 4aae58
Wall time: 5.0012 seconds
Process running with session ID 74526
Original token count: 2064
Output:
shape {'M': 32, 'N': 8192, 'K': 8192}
(32, 32, 64, 4, 3, 1) ms=0.0890 tf=48.2 gb=763
(32, 32, 64, 4, 3, 2) ms=0.0899 tf=47.8 gb=755
(32, 32, 64, 4, 3, 4) ms=0.0901 tf=47.7 gb=753
(32, 32, 64, 4, 3, 8) ms=0.0908 tf=47.3 gb=748
(32, 32, 64, 4, 4, 1) ms=0.0808 tf=53.1 gb=840
(32, 32, 64, 4, 4, 2) ms=0.0811 tf=52.9 gb=837
(32, 32, 64, 4, 4, 4) ms=0.0824 tf=52.1 gb=824
(32, 32, 64, 4, 4, 8) ms=0.0810 tf=53.0 gb=838
(32, 32, 64, 8, 3, 1) ms=0.0896 tf=48.0 gb=758
(32, 32, 64, 8, 3, 2) ms=0.0912 tf=47.1 gb=744
(32, 32, 64, 8, 3, 4) ms=0.0912 tf=47.1 gb=745
(32, 32, 64, 8, 3, 8) ms=0.0903 tf=47.6 gb=752
(32, 32, 64, 8, 4, 1) ms=0.0825 tf=52.1 gb=823
(32, 32, 64, 8, 4, 2) ms=0.0830 tf=51.8 gb=818
(32, 32, 64, 8, 4, 4) ms=0.0834 tf=51.5 gb=814
(32, 32, 64, 8, 4, 8) ms=0.0843 tf=50.9 gb=805
(32, 32, 128, 4, 3, 1) ms=0.0718 tf=59.9 gb=946
(32, 32, 128, 4, 3, 2) ms=0.0673 tf=63.8 gb=1009
(32, 32, 128, 4, 3, 4) ms=0.0686 tf=62.6 gb=990
(32, 32, 128, 4, 3, 8) ms=0.0692 tf=62.0 gb=981
(32, 32, 128, 4, 4, 1) ms=0.0575 tf=74.7 gb=1180
(32, 32, 128, 4, 4, 2) ms=0.0589 tf=73.0 gb=1153
(32, 32, 128, 4, 4, 4) ms=0.0584 tf=73.5 gb=1162
(32, 32, 128, 4, 4, 8) ms=0.0579 tf=74.2 gb=1172
(32, 32, 128, 8, 3, 1) ms=0.0677 tf=63.4 gb=1002
(32, 32, 128, 8, 3, 2) ms=0.0678 tf=63.4 gb=1002
(32, 32, 128, 8, 3, 4) ms=0.0683 tf=62.9 gb=995
(32, 32, 128, 8, 3, 8) ms=0.0676 tf=63.6 gb=1005
(32, 32, 1

... (6872 more chars)
assistant
Skinny-M improves modestly with `BLOCK_K=256`; best candidates are around 0.054 ms versus the current 0.060 ms. That is near 1.25 TB/s under the harness’s L2-flush methodology, so gains here are mostly memory scheduling rather than FP8 peak.
assistant
write_stdin
args
{
  "session_id": 74526,
  "chars": "",
  "yield_time_ms": 5000,
  "max_output_tokens": 50000
}
tool
stdout (6982 chars) — TRUNCATED
Chunk ID: c9b0da
Wall time: 5.0012 seconds
Process running with session ID 74526
Original token count: 1717
Output:
(32, 256, 64, 4, 4, 4) ms=0.0713 tf=60.3 gb=953
(32, 256, 64, 4, 4, 8) ms=0.0721 tf=59.6 gb=942
(32, 256, 64, 8, 3, 1) ms=0.0949 tf=45.3 gb=716
(32, 256, 64, 8, 3, 2) ms=0.0947 tf=45.4 gb=717
(32, 256, 64, 8, 3, 4) ms=0.0947 tf=45.4 gb=717
(32, 256, 64, 8, 3, 8) ms=0.0946 tf=45.4 gb=717
(32, 256, 64, 8, 4, 1) ms=0.0728 tf=59.0 gb=932
(32, 256, 64, 8, 4, 2) ms=0.0725 tf=59.3 gb=937
(32, 256, 64, 8, 4, 4) ms=0.0723 tf=59.4 gb=940
(32, 256, 64, 8, 4, 8) ms=0.0728 tf=59.0 gb=932
(32, 256, 128, 4, 3, 1) ms=0.0632 tf=68.0 gb=1075
(32, 256, 128, 4, 3, 2) ms=0.0634 tf=67.8 gb=1071
(32, 256, 128, 4, 3, 4) ms=0.0635 tf=67.7 gb=1070
(32, 256, 128, 4, 3, 8) ms=0.0629 tf=68.3 gb=1079
(32, 256, 128, 4, 4, 1) ERR OutOfResources: out of resource: shared memory, Required: 110592, Hardware limit: 101376. Reducing block sizes or `num_stages` may help.
(32, 256, 128, 4, 4, 2) ERR OutOfResources: out of resource: shared memory, Required: 110592, Hardware limit: 101376. Reducing block sizes or `num_stages` may help.
(32, 256, 128, 4, 4, 4) ERR OutOfResources: out of resource: shared memory, Required: 110592, Hardware limit: 101376. Reducing block sizes or `num_stages` may help.
(32, 256, 128, 4, 4, 8) ERR OutOfResources: out of resource: shared memory, Required: 110592, Hardware limit: 101376. Reducing block sizes or `num_stages` may help.
(32, 256, 128, 8, 3, 1) ms=0.0628 tf=68.4 gb

... (5482 more chars)
assistant
exec_command
args
{
  "cmd": "pkill -f \"uv run python -\" || true",
  "workdir": "/workspace/problems/01_fp8_gemm",
  "yield_time_ms": 1000,
  "max_output_tokens": 4000
}
tool
stdout (103 chars)
Chunk ID: dd37b0
Wall time: 0.0000 seconds
Process exited with code -1
Original token count: 0
Output:
assistant
I’m applying the tuned launch choices now and removing the transposed-weight path from `forward`. The selected configs are: skinny `32x64x256`, odd-K `128x128x128`, square aligned `256x128x64`, and wide-N aligned `128x256x64`.
assistant
apply_patch /workspace/problems/01_fp8_gemm/solution.py
diff (114 lines)
--- a//workspace/problems/01_fp8_gemm/solution.py
+++ b//workspace/problems/01_fp8_gemm/solution.py
@@ -1,94 +1,30 @@
-@triton.jit
-def _fp8_gemm_kernel(
-    )
-
-
-@triton.jit
-def _fp8_gemm_wt_kernel(
-    x_ptr,
-    wt_ptr,
-    scale_ptr,
-    y_ptr,
-    M: tl.constexpr,
-    N: tl.constexpr,
-    K: tl.constexpr,
-    BLOCK_M: tl.constexpr,
-    BLOCK_N: tl.constexpr,
-    BLOCK_K: tl.constexpr,
-    GROUP_M: tl.constexpr,
-):
-    pid = tl.program_id(0)
-    num_pid_m = tl.cdiv(M, BLOCK_M)
-    num_pid_n = tl.cdiv(N, BLOCK_N)
-    group_size = GROUP_M * num_pid_n
-    group_id = pid // group_size
-    first_pid_m = group_id * GROUP_M
-    group_m = tl.minimum(num_pid_m - first_pid_m, GROUP_M)
-    pid_in_group = pid - group_id * group_size
-    pid_m = first_pid_m + (pid_in_group % group_m)
-    pid_n = pid_in_group // group_m
-
-    offs_m = pid_m * BLOCK_M + tl.arange(0, BLOCK_M)
-    offs_n = pid_n * BLOCK_N + tl.arange(0, BLOCK_N)
-    offs_k = tl.arange(0, BLOCK_K)
-
-    acc = tl.zeros((BLOCK_M, BLOCK_N), tl.float32)
-    full_k = (K // BLOCK_K) * BLOCK_K
-    for k0 in range(0, full_k, BLOCK_K):
-        k = k0 + offs_k
-        a = tl.load(x_ptr + offs_m[:, None] * K + k[None, :])
-        b = tl.load(wt_ptr + k[:, None] * N + offs_n[None, :])
-        acc = tl.dot(a, b, acc, out_dtype=tl.float32)
-
-    if full_k < K:
-        k = full_k + offs_k
-        a = tl.load(
-            x_ptr + offs_m[:, None] * K + k[None, :],
-            mask=k[None, :] < K,
-            other=0.0,
-        )
-        b = tl.load(
-            wt_ptr + k[:, None] * N + offs_n[None, :],
-            mask=k[:, None] < K,
-            other=0.0,
-        )
-        acc = tl.dot(a, b, acc, out_dtype=tl.float32)
-
-    scales = tl.load(scale_ptr + offs_n, mask=offs_n < N, other=0.0)
-    acc = acc * scales[None, :]
-    tl.store(
-        y_ptr + offs_m[:, None] * N + offs_n[None, :],
-        acc,
-        mask=(offs_m[:, None] < M) & (offs_n[None, :] < N),
-    )
-
-
-def _launch_fp8_gemm(x: torch.Tensor, weight_t: torch.Tensor, weight_scale: torch.Tensor, M: int, N: int, K: int):
+def _launch_fp8_gemm(x: torch.Tensor, weight: torch.Tensor, weight_scale: torch.Tensor, M: int, N: int, K: int):
     y = torch.empty((M, N), device=x.device, dtype=torch.bfloat16)
 
     if M <= 64:
-        bm, bn, bk = 32, 128, 128
-        warps, stages, group_m = 4, 4, 4
+        bm, bn, bk = 32, 64, 256
+        warps, stages, group_m = 8, 3, 2
+    elif K % 128 != 0:
+        bm, bn, bk = 128, 128, 128
+        warps, stages, group_m = 4, 3, 8
+    elif N >= 8192:
+        bm, bn, bk = 128, 256, 64
+        warps, stages, group_m = 8, 4, 2
+    else:
+        bm, bn, bk = 256, 128, 64
+        warps, stages, group_m = 8, 4, 4
+
     grid = (triton.cdiv(M, bm) * triton.cdiv(N, bn),)
-    _fp8_gemm_wt_kernel[grid](
+    _fp8_gemm_kernel[grid](
         x,
-        weight_t,
+        weight,
         weight_scale,
         y,
         M,
+        super().__init__()
         self.M, self.N, self.K = M, N, K
-        self._weight_t = None
-        self._weight_t_key = None
         w = torch.empty(N, K, dtype=torch.bfloat16)
-    def forward(self, x: torch.Tensor) -> torch.Tensor:
-        if not x.is_cuda:
-            x_bf = x.to(torch.bfloat16)
-            w_bf = self.weight.to(torch.bfloat16)
             y = (x_bf @ w_bf.T).float()
             y = y * self.weight_scale[None, :]
             return y.to(torch.bfloat16)
-        key = (self.weight.data_ptr(), self.weight._version, self.weight.device, self.weight.shape)
-        if self._weight_t is None or self._weight_t_key != key:
-            self._weight_t = self.weight.t().contiguous()
-            self._weight_t_key = key
-        return _launch_fp8_gemm(x, self._weight_t, self.weight_scale, self.M, self.N, self.K)
+        return _launch_fp8_gemm(x, self.weight, self.weight_scale, self.M, self.N, self.K)
args
{
  "raw": "<1996 chars \u2014 see below>"
}
raw (1996 chars)
*** Begin Patch
*** Update File: /workspace/problems/01_fp8_gemm/solution.py
@@
-def _launch_fp8_gemm(x: torch.Tensor, weight_t: torch.Tensor, weight_scale: torch.Tensor, M: int, N: int, K: int):
+def _launch_fp8_gemm(x: torch.Tensor, weight: torch.Tensor, weight_scale: torch.Tensor, M: int, N: int, K: int):
     y = torch.empty((M, N), device=x.device, dtype=torch.bfloat16)
 
     if M <= 64:
-        bm, bn, bk = 32, 128, 128
-        warps, stages, group_m = 4, 4, 4
+        bm, bn, bk = 32, 64, 256
+        warps, stages, group_m = 8, 3, 2
+    elif K % 128 != 0:
+        bm, bn, bk = 128, 128, 128
+        warps, stages, group_m = 4, 3, 8
     elif N >= 8192:
-        bm, bn, bk = 128, 128, 128
-        warps, stages, group_m = 4, 4, 4
+        bm, bn, bk = 128, 256, 64
+        warps, stages, group_m = 8, 4, 2
     else:
-        bm, bn, bk = 128, 128, 128
-        warps, stages, group_m = 4, 4, 4
+        bm, bn, bk = 256, 128, 64
+        warps, stages, group_m = 8, 4, 4
 
     grid = (triton.cdiv(M, bm) * triton.cdiv(N, bn),)
-    _fp8_gemm_wt_kernel[grid](
+    _fp8_gemm_kernel[grid](
         x,
-        weight_t,
+        weight,
         weight_scale,
         y,
         M,
@@
         super().__init__()
         self.M, self.N, self.K = M, N, K
-        self._weight_t = None
-        self._weight_t_key = None
         w = torch.empty(N, K, dtype=torch.bfloat16)
@@
             y = (x_bf @ w_bf.T).float()
             y = y * self.weight_scale[None, :]
             return y.to(torch.bfloat16)
-        key = (self.weight.data_ptr(), self.weight._version, self.weight.device, self.weight.shape)
-        if self._weight_t is None or self._weight_t_key != key:
-            self._weight_t = self.weight.t().contiguous()
-            self._weight_t_key = key
-        return _launch_fp8_gemm(x, self._weight_t, self.weight_scale, self.M, self.N, self.K)
+        return _launch_fp8_gemm(x, self.weight, self.weight_scale, self.M, self.N, self.K)
*** End Patch
tool
stdout (144 chars)
output:
  Success. Updated the following files:
  M /workspace/problems/01_fp8_gemm/solution.py
metadata:
  exit_code: 0
  duration_seconds: 0.0
assistant
The tuned wrapper is in place. I’m running `check.py` again now, because the large-tile configs remove load masks in the main loop and must still pass every shape and stress case.
assistant
exec_command
args
{
  "cmd": "uv run python check.py",
  "workdir": "/workspace/problems/01_fp8_gemm",
  "yield_time_ms": 1000,
  "max_output_tokens": 20000
}
tool
stdout (113 chars)
Chunk ID: f90bc4
Wall time: 1.0007 seconds
Process running with session ID 63402
Original token count: 0
Output:
assistant
write_stdin
args
{
  "session_id": 63402,
  "chars": "",
  "yield_time_ms": 1000,
  "max_output_tokens": 20000
}
tool
stdout (107 chars)
Chunk ID: b209df
Wall time: 3.0177 seconds
Process exited with code 0
Original token count: 2
Output:
PASS
assistant
Correctness passes after tuning. I’m running the official benchmark now to measure the final wrapper choices end to end.
assistant
exec_command
args
{
  "cmd": "uv run python benchmark.py",
  "workdir": "/workspace/problems/01_fp8_gemm",
  "yield_time_ms": 1000,
  "max_output_tokens": 20000
}
tool
stdout (211 chars)
Chunk ID: 216c7a
Wall time: 1.0015 seconds
Process running with session ID 30718
Original token count: 25
Output:
benchmark_event event=variant_start shape=0 variant=solution ts=2026-06-14T20:51:26.294215+00:00
assistant
write_stdin
args
{
  "session_id": 30718,
  "chars": "",
  "yield_time_ms": 1000,
  "max_output_tokens": 20000
}
tool
stdout (1320 chars)
Chunk ID: aa952c
Wall time: 2.5876 seconds
Process exited with code 0
Original token count: 304
Output:
benchmark_event event=variant_end shape=0 variant=solution ts=2026-06-14T20:51:26.500679+00:00 elapsed_s=0.206 ms=0.220400
shape=0 variant=solution tflops=623.589 gbps=304.487 ms=0.220
shape=0 solution_peak_fraction=0.6236
benchmark_event event=variant_start shape=1 variant=solution ts=2026-06-14T20:51:27.008943+00:00
benchmark_event event=variant_end shape=1 variant=solution ts=2026-06-14T20:51:27.029527+00:00 elapsed_s=0.021 ms=0.430400
shape=1 variant=solution tflops=321.745 gbps=156.512 ms=0.430
shape=1 solution_peak_fraction=0.3217
benchmark_event event=variant_start shape=2 variant=solution ts=2026-06-14T20:51:28.877432+00:00
benchmark_event event=variant_end shape=2 variant=solution ts=2026-06-14T20:51:28.883009+00:00 elapsed_s=0.006 ms=0.058224
shape=2 variant=solution tflops=73.766 gbps=1166.105 ms=0.058
shape=2 solution_peak_fraction=0.0738
benchmark_event event=variant_start shape=3 variant=solution ts=2026-06-14T20:51:30.557252+00:00
benchmark_event event=variant_end shape=3 variant=solution ts=2026-06-14T20:51:30.589028+00:00 elapsed_s=0.032 ms=0.707104
shape=3 variant=solution tflops=680.291 gbps=272.857 ms=0.707
shape=3 solution_peak_fraction=0.6803
peak_fraction: 0.3168
RESULT: OK
assistant
The remaining weak shape is K=4127. I’m testing a more practical odd-K strategy: pad the activation and static weight to a 128-multiple K, then run the faster aligned kernel. First I’ll measure it with the activation padding included in every timed call, so the result is not just a cache artifact.
assistant
exec_command
args
{
  "cmd": "<1484 chars \u2014 see below>",
  "workdir": "/workspace/problems/01_fp8_gemm",
  "yield_time_ms": 1000,
  "max_output_tokens": 20000
}
cmd (1484 chars)
uv run python - <<'PY'
import torch, triton
import reference, solution, shapes
from src.eval.timing import time_fn
from src.eval.roofline import compute_tflops

device='cuda'
shape=shapes.SHAPES[1]
M,N,K=shape['M'],shape['N'],shape['K']
Kp=((K+127)//128)*128
reference.M,reference.N,reference.K=M,N,K
ref=reference.Model(M,N,K).to(device).eval()
x=reference.get_inputs()[0].to(device)
w_pad=torch.empty((N,Kp),device=device,dtype=torch.float8_e4m3fn)
w_pad[:, :K].copy_(ref.weight)
w_pad[:, K:].zero_()
x_pad=torch.empty((M,Kp),device=device,dtype=torch.float8_e4m3fn)
y=torch.empty((M,N),device=device,dtype=torch.bfloat16)
configs=[
 (256,128,64,8,4,4),(128,256,64,8,4,2),(128,128,64,4,3,4),(128,128,128,4,3,8),(256,128,128,8,3,4)
]
print('Kp',Kp, flush=True)
for cfg in configs:
  bm,bn,bk,warps,stages,gm=cfg
  grid=(triton.cdiv(M,bm)*triton.cdiv(N,bn),)
  def gemm():
    solution._fp8_gemm_kernel[grid](x_pad,w_pad,ref.weight_scale,y,M,N,Kp,BLOCK_M=bm,BLOCK_N=bn,BLOCK_K=bk,GROUP_M=gm,num_warps=warps,num_stages=stages)
    return y
  def pack_gemm():
    x_pad[:, :K].copy_(x)
    x_pad[:, K:].zero_()
    return gemm()
  try:
    ms=time_fn(lambda: pack_gemm(), [], iters=20, warmup=5)
    ms2=time_fn(lambda: gemm(), [], iters=20, warmup=5)
    print(cfg, 'pack+gemm', f'{ms:.4f}', 'tf', f'{compute_tflops(2*M*N*K,ms):.1f}', 'gemm_only', f'{ms2:.4f}', flush=True)
  except Exception as e:
    print(cfg, 'ERR', type(e).__name__, e, flush=True)
    torch.cuda.synchronize()
PY
tool
stdout (113 chars)
Chunk ID: e27acb
Wall time: 1.0019 seconds
Process running with session ID 71821
Original token count: 0
Output:
assistant
The padding experiment is running. If `pack+gemm` lands near the aligned time, it may be worth adding a dedicated odd-K path with a reusable padding buffer and a cached padded weight.
assistant
write_stdin
args
{
  "session_id": 71821,
  "chars": "",
  "yield_time_ms": 5000,
  "max_output_tokens": 20000
}
tool
stdout (113 chars)
Chunk ID: 059568
Wall time: 5.0020 seconds
Process running with session ID 71821
Original token count: 0
Output:
assistant
write_stdin
args
{
  "session_id": 71821,
  "chars": "",
  "yield_time_ms": 5000,
  "max_output_tokens": 20000
}
tool
stdout (448 chars)
Chunk ID: 775dfe
Wall time: 3.8818 seconds
Process exited with code 0
Original token count: 87
Output:
Kp 4224
(256, 128, 64, 8, 4, 4) pack+gemm 0.2492 tf 555.7 gemm_only 0.2219
(128, 256, 64, 8, 4, 2) pack+gemm 0.2498 tf 554.4 gemm_only 0.2221
(128, 128, 64, 4, 3, 4) pack+gemm 0.2536 tf 546.1 gemm_only 0.2276
(128, 128, 128, 4, 3, 8) pack+gemm 0.2600 tf 532.6 gemm_only 0.2320
(256, 128, 128, 8, 3, 4) pack+gemm 0.2409 tf 574.7 gemm_only 0.2127
assistant
The odd-K padding path is clearly faster even with per-call activation padding included: about 0.241 ms versus 0.430 ms. I’m adding that as the dedicated K=4127 path with cached padded weights and a reusable activation padding buffer, while still copying the activation each forward.
assistant
apply_patch /workspace/problems/01_fp8_gemm/solution.py
diff (57 lines)
--- a//workspace/problems/01_fp8_gemm/solution.py
+++ b//workspace/problems/01_fp8_gemm/solution.py
@@ -1,30 +1,37 @@
-def _launch_fp8_gemm(x: torch.Tensor, weight: torch.Tensor, weight_scale: torch.Tensor, M: int, N: int, K: int):
-    y = torch.empty((M, N), device=x.device, dtype=torch.bfloat16)
-
     if M <= 64:
         bm, bn, bk = 32, 64, 256
         warps, stages, group_m = 8, 3, 2
+    elif K == 4224 and M == 4096 and N == 4096:
+        bm, bn, bk = 256, 128, 128
+        warps, stages, group_m = 8, 3, 4
     elif K % 128 != 0:
         bm, bn, bk = 128, 128, 128
         warps, stages, group_m = 4, 3, 8
-    elif N >= 8192:
-        bm, bn, bk = 128, 256, 64
-        warps, stages, group_m = 8, 4, 2
-    else:
-        bm, bn, bk = 256, 128, 64
-        warps, stages, group_m = 8, 4, 4
-
-    grid = (triton.cdiv(M, bm) * triton.cdiv(N, bn),)
-    _fp8_gemm_kernel[grid](
-        x,
-        weight,
-        weight_scale,
-        y,
-        M,
         super().__init__()
         self.M, self.N, self.K = M, N, K
+        self._weight_pad = None
+        self._weight_pad_key = None
+        self._x_pad = None
         w = torch.empty(N, K, dtype=torch.bfloat16)
             y = (x_bf @ w_bf.T).float()
             y = y * self.weight_scale[None, :]
             return y.to(torch.bfloat16)
+        if self.K % 128 != 0:
+            k_pad = ((self.K + 127) // 128) * 128
+            w_key = (self.weight.data_ptr(), self.weight._version, self.weight.device, self.weight.shape)
+            if self._weight_pad is None or self._weight_pad_key != w_key:
+                weight_pad = torch.empty((self.N, k_pad), device=x.device, dtype=self.weight.dtype)
+                weight_pad[:, : self.K].copy_(self.weight)
+                weight_pad[:, self.K :].zero_()
+                self._weight_pad = weight_pad
+                self._weight_pad_key = w_key
+            if (
+                self._x_pad is None
+                or self._x_pad.device != x.device
+                or self._x_pad.shape != (self.M, k_pad)
+            ):
+                self._x_pad = torch.empty((self.M, k_pad), device=x.device, dtype=x.dtype)
+            self._x_pad[:, : self.K].copy_(x)
+            self._x_pad[:, self.K :].zero_()
+            return _launch_fp8_gemm(self._x_pad, self._weight_pad, self.weight_scale, self.M, self.N, k_pad)
         return _launch_fp8_gemm(x, self.weight, self.weight_scale, self.M, self.N, self.K)
args
{
  "raw": "<1906 chars \u2014 see below>"
}
raw (1906 chars)
*** Begin Patch
*** Update File: /workspace/problems/01_fp8_gemm/solution.py
@@
     if M <= 64:
         bm, bn, bk = 32, 64, 256
         warps, stages, group_m = 8, 3, 2
+    elif K == 4224 and M == 4096 and N == 4096:
+        bm, bn, bk = 256, 128, 128
+        warps, stages, group_m = 8, 3, 4
     elif K % 128 != 0:
         bm, bn, bk = 128, 128, 128
         warps, stages, group_m = 4, 3, 8
@@
         super().__init__()
         self.M, self.N, self.K = M, N, K
+        self._weight_pad = None
+        self._weight_pad_key = None
+        self._x_pad = None
         w = torch.empty(N, K, dtype=torch.bfloat16)
@@
             y = (x_bf @ w_bf.T).float()
             y = y * self.weight_scale[None, :]
             return y.to(torch.bfloat16)
+        if self.K % 128 != 0:
+            k_pad = ((self.K + 127) // 128) * 128
+            w_key = (self.weight.data_ptr(), self.weight._version, self.weight.device, self.weight.shape)
+            if self._weight_pad is None or self._weight_pad_key != w_key:
+                weight_pad = torch.empty((self.N, k_pad), device=x.device, dtype=self.weight.dtype)
+                weight_pad[:, : self.K].copy_(self.weight)
+                weight_pad[:, self.K :].zero_()
+                self._weight_pad = weight_pad
+                self._weight_pad_key = w_key
+            if (
+                self._x_pad is None
+                or self._x_pad.device != x.device
+                or self._x_pad.shape != (self.M, k_pad)
+            ):
+                self._x_pad = torch.empty((self.M, k_pad), device=x.device, dtype=x.dtype)
+            self._x_pad[:, : self.K].copy_(x)
+            self._x_pad[:, self.K :].zero_()
+            return _launch_fp8_gemm(self._x_pad, self._weight_pad, self.weight_scale, self.M, self.N, k_pad)
         return _launch_fp8_gemm(x, self.weight, self.weight_scale, self.M, self.N, self.K)
*** End Patch
tool
stdout (144 chars)
output:
  Success. Updated the following files:
  M /workspace/problems/01_fp8_gemm/solution.py
metadata:
  exit_code: 0
  duration_seconds: 0.0
assistant
The padded odd-K path is implemented. I’m running the full correctness suite again; this also validates that the cached padded weight refreshes correctly when the stress harness scales the weight buffer.
assistant
exec_command
args
{
  "cmd": "uv run python check.py",
  "workdir": "/workspace/problems/01_fp8_gemm",
  "yield_time_ms": 1000,
  "max_output_tokens": 20000
}
tool
stdout (113 chars)
Chunk ID: 4c35b9
Wall time: 1.0011 seconds
Process running with session ID 27446
Original token count: 0
Output:
assistant
write_stdin
args
{
  "session_id": 27446,
  "chars": "",
  "yield_time_ms": 1000,
  "max_output_tokens": 20000
}
tool
stdout (113 chars)
Chunk ID: d89fda
Wall time: 5.0011 seconds
Process running with session ID 27446
Original token count: 0
Output:
assistant
write_stdin
args
{
  "session_id": 27446,
  "chars": "",
  "yield_time_ms": 1000,
  "max_output_tokens": 20000
}
tool
stdout (107 chars)
Chunk ID: 245a51
Wall time: 0.0000 seconds
Process exited with code 0
Original token count: 2
Output:
PASS
assistant
Correctness passes with padding. I’m benchmarking again to see the net gain on shape 1 and confirm the other tuned paths are unchanged.
assistant
exec_command
args
{
  "cmd": "uv run python benchmark.py",
  "workdir": "/workspace/problems/01_fp8_gemm",
  "yield_time_ms": 1000,
  "max_output_tokens": 20000
}
tool
stdout (211 chars)
Chunk ID: 5fffb0
Wall time: 1.0010 seconds
Process running with session ID 26285
Original token count: 25
Output:
benchmark_event event=variant_start shape=0 variant=solution ts=2026-06-14T20:53:18.923402+00:00
assistant
write_stdin
args
{
  "session_id": 26285,
  "chars": "",
  "yield_time_ms": 1000,
  "max_output_tokens": 20000
}
tool
stdout (1320 chars)
Chunk ID: 2cfb8a
Wall time: 2.6728 seconds
Process exited with code 0
Original token count: 304
Output:
benchmark_event event=variant_end shape=0 variant=solution ts=2026-06-14T20:53:19.134649+00:00 elapsed_s=0.211 ms=0.221360
shape=0 variant=solution tflops=620.884 gbps=303.166 ms=0.221
shape=0 solution_peak_fraction=0.6209
benchmark_event event=variant_start shape=1 variant=solution ts=2026-06-14T20:53:19.656391+00:00
benchmark_event event=variant_end shape=1 variant=solution ts=2026-06-14T20:53:19.673378+00:00 elapsed_s=0.017 ms=0.244800
shape=1 variant=solution tflops=565.683 gbps=275.175 ms=0.245
shape=1 solution_peak_fraction=0.5657
benchmark_event event=variant_start shape=2 variant=solution ts=2026-06-14T20:53:21.553364+00:00
benchmark_event event=variant_end shape=2 variant=solution ts=2026-06-14T20:53:21.559192+00:00 elapsed_s=0.006 ms=0.061488
shape=2 variant=solution tflops=69.850 gbps=1104.204 ms=0.061
shape=2 solution_peak_fraction=0.0699
benchmark_event event=variant_start shape=3 variant=solution ts=2026-06-14T20:53:23.291422+00:00
benchmark_event event=variant_end shape=3 variant=solution ts=2026-06-14T20:53:23.323374+00:00 elapsed_s=0.032 ms=0.710272
shape=3 variant=solution tflops=677.256 gbps=271.640 ms=0.710
shape=3 solution_peak_fraction=0.6773
peak_fraction: 0.3590
RESULT: OK
assistant
The odd-K path moved shape 1 from ~322 to ~566 TFLOP/s, which is the main gain. Shape 2 showed variance and came back slightly worse than the tuning run, so I’m going to retime a few skinny configs under the exact harness timing before locking that branch.
assistant
exec_command
args
{
  "cmd": "<1218 chars \u2014 see below>",
  "workdir": "/workspace/problems/01_fp8_gemm",
  "yield_time_ms": 1000,
  "max_output_tokens": 20000
}
cmd (1218 chars)
uv run python - <<'PY'
import torch, triton
import reference, solution, shapes
from src.eval.timing import time_fn
from src.eval.roofline import compute_tflops, compute_gbps

device='cuda'
M,N,K=32,8192,8192
reference.M,reference.N,reference.K=M,N,K
ref=reference.Model(M,N,K).to(device).eval()
x=reference.get_inputs()[0].to(device)
configs=[
 (32,128,128,4,4,4), # original
 (32,128,128,4,4,8),
 (32,64,256,8,3,2),
 (32,64,256,8,3,1),
 (32,64,256,4,4,8),
 (32,128,256,8,3,1),
 (32,128,256,8,3,4),
 (32,32,256,4,4,1),
 (32,32,256,8,4,1),
]
bytes_moved=M*K+K*N+M*N*2
for cfg in configs:
    bm,bn,bk,warps,stages,gm=cfg
    y=torch.empty((M,N),device=device,dtype=torch.bfloat16)
    grid=(triton.cdiv(M,bm)*triton.cdiv(N,bn),)
    def fn():
        solution._fp8_gemm_kernel[grid](x,ref.weight,ref.weight_scale,y,M,N,K,BLOCK_M=bm,BLOCK_N=bn,BLOCK_K=bk,GROUP_M=gm,num_warps=warps,num_stages=stages)
        return y
    try:
      ms=time_fn(lambda: fn(), [], iters=30, warmup=10)
      print(cfg, f'ms={ms:.6f}', f'tf={compute_tflops(2*M*N*K,ms):.3f}', f'gb={compute_gbps(bytes_moved,ms):.1f}', flush=True)
    except Exception as e:
      print(cfg, type(e).__name__, e, flush=True)
      torch.cuda.synchronize()
PY
tool
stdout (113 chars)
Chunk ID: 0a9a5f
Wall time: 1.0011 seconds
Process running with session ID 74930
Original token count: 0
Output:
assistant
write_stdin
args
{
  "session_id": 74930,
  "chars": "",
  "yield_time_ms": 5000,
  "max_output_tokens": 20000
}
tool
stdout (603 chars)
Chunk ID: ef4bea
Wall time: 0.0000 seconds
Process exited with code 0
Original token count: 125
Output:
(32, 128, 128, 4, 4, 4) ms=0.055968 tf=76.740 gb=1213.1
(32, 128, 128, 4, 4, 8) ms=0.055328 tf=77.627 gb=1227.1
(32, 64, 256, 8, 3, 2) ms=0.054144 tf=79.325 gb=1254.0
(32, 64, 256, 8, 3, 1) ms=0.054112 tf=79.372 gb=1254.7
(32, 64, 256, 4, 4, 8) ms=0.055632 tf=77.203 gb=1220.4
(32, 128, 256, 8, 3, 1) ms=0.054256 tf=79.161 gb=1251.4
(32, 128, 256, 8, 3, 4) ms=0.054000 tf=79.536 gb=1257.3
(32, 32, 256, 4, 4, 1) ms=0.053968 tf=79.584 gb=1258.1
(32, 32, 256, 8, 4, 1) ms=0.054544 tf=78.743 gb=1244.8
assistant
The exact skinny retime favors `32x32x256`, 4 warps, 4 stages. I’m switching the skinny branch to that; it gives about 0.054 ms in isolation and avoids the variance seen in the full benchmark.
assistant
apply_patch /workspace/problems/01_fp8_gemm/solution.py
diff (42 lines)
--- a//workspace/problems/01_fp8_gemm/solution.py
+++ b//workspace/problems/01_fp8_gemm/solution.py
@@ -1,37 +1,3 @@
     if M <= 64:
-        bm, bn, bk = 32, 64, 256
-        warps, stages, group_m = 8, 3, 2
-    elif K == 4224 and M == 4096 and N == 4096:
-        bm, bn, bk = 256, 128, 128
-        warps, stages, group_m = 8, 3, 4
-    elif K % 128 != 0:
-        bm, bn, bk = 128, 128, 128
-        warps, stages, group_m = 4, 3, 8
-        super().__init__()
-        self.M, self.N, self.K = M, N, K
-        self._weight_pad = None
-        self._weight_pad_key = None
-        self._x_pad = None
-        w = torch.empty(N, K, dtype=torch.bfloat16)
-            y = (x_bf @ w_bf.T).float()
-            y = y * self.weight_scale[None, :]
-            return y.to(torch.bfloat16)
-        if self.K % 128 != 0:
-            k_pad = ((self.K + 127) // 128) * 128
-            w_key = (self.weight.data_ptr(), self.weight._version, self.weight.device, self.weight.shape)
-            if self._weight_pad is None or self._weight_pad_key != w_key:
-                weight_pad = torch.empty((self.N, k_pad), device=x.device, dtype=self.weight.dtype)
-                weight_pad[:, : self.K].copy_(self.weight)
-                weight_pad[:, self.K :].zero_()
-                self._weight_pad = weight_pad
-                self._weight_pad_key = w_key
-            if (
-                self._x_pad is None
-                or self._x_pad.device != x.device
-                or self._x_pad.shape != (self.M, k_pad)
-            ):
-                self._x_pad = torch.empty((self.M, k_pad), device=x.device, dtype=x.dtype)
-            self._x_pad[:, : self.K].copy_(x)
-            self._x_pad[:, self.K :].zero_()
-            return _launch_fp8_gemm(self._x_pad, self._weight_pad, self.weight_scale, self.M, self.N, k_pad)
-        return _launch_fp8_gemm(x, self.weight, self.weight_scale, self.M, self.N, self.K)
+        bm, bn, bk = 32, 32, 256
+        warps, stages, group_m = 4, 4, 1
args
{
  "raw": "<263 chars \u2014 see below>"
}
raw (263 chars)
*** Begin Patch
*** Update File: /workspace/problems/01_fp8_gemm/solution.py
@@
     if M <= 64:
-        bm, bn, bk = 32, 64, 256
-        warps, stages, group_m = 8, 3, 2
+        bm, bn, bk = 32, 32, 256
+        warps, stages, group_m = 4, 4, 1
*** End Patch
tool
stdout (144 chars)
output:
  Success. Updated the following files:
  M /workspace/problems/01_fp8_gemm/solution.py
metadata:
  exit_code: 0
  duration_seconds: 0.0
assistant
The skinny branch is updated. I’m doing another full `check.py` run, then I’ll take a final benchmark reading.
assistant
exec_command
args
{
  "cmd": "uv run python check.py",
  "workdir": "/workspace/problems/01_fp8_gemm",
  "yield_time_ms": 1000,
  "max_output_tokens": 20000
}
tool
stdout (113 chars)
Chunk ID: 901dc7
Wall time: 1.0010 seconds
Process running with session ID 41980
Original token count: 0
Output:
assistant
The checker is compiling the new skinny specialization along with the existing padded odd-K path. No failures have printed so far.
assistant
write_stdin
args
{
  "session_id": 41980,
  "chars": "",
  "yield_time_ms": 1000,
  "max_output_tokens": 20000
}
tool
stdout (107 chars)
Chunk ID: 7a21b0
Wall time: 2.3475 seconds
Process exited with code 0
Original token count: 2
Output:
PASS
assistant
Correctness passes. I’m running the final benchmark pass now.
assistant
exec_command
args
{
  "cmd": "uv run python benchmark.py",
  "workdir": "/workspace/problems/01_fp8_gemm",
  "yield_time_ms": 1000,
  "max_output_tokens": 20000
}
tool
stdout (211 chars)
Chunk ID: 14d5c7
Wall time: 1.0007 seconds
Process running with session ID 72517
Original token count: 25
Output:
benchmark_event event=variant_start shape=0 variant=solution ts=2026-06-14T20:54:02.710334+00:00
assistant
write_stdin
args
{
  "session_id": 72517,
  "chars": "",
  "yield_time_ms": 1000,
  "max_output_tokens": 20000
}
tool
stdout (1320 chars)
Chunk ID: a721b3
Wall time: 2.4992 seconds
Process exited with code 0
Original token count: 304
Output:
benchmark_event event=variant_end shape=0 variant=solution ts=2026-06-14T20:54:02.918219+00:00 elapsed_s=0.208 ms=0.219584
shape=0 variant=solution tflops=625.906 gbps=305.618 ms=0.220
shape=0 solution_peak_fraction=0.6259
benchmark_event event=variant_start shape=1 variant=solution ts=2026-06-14T20:54:03.434926+00:00
benchmark_event event=variant_end shape=1 variant=solution ts=2026-06-14T20:54:03.451667+00:00 elapsed_s=0.017 ms=0.244736
shape=1 variant=solution tflops=565.831 gbps=275.247 ms=0.245
shape=1 solution_peak_fraction=0.5658
benchmark_event event=variant_start shape=2 variant=solution ts=2026-06-14T20:54:05.299032+00:00
benchmark_event event=variant_end shape=2 variant=solution ts=2026-06-14T20:54:05.304584+00:00 elapsed_s=0.006 ms=0.058288
shape=2 variant=solution tflops=73.685 gbps=1164.825 ms=0.058
shape=2 solution_peak_fraction=0.0737
benchmark_event event=variant_start shape=3 variant=solution ts=2026-06-14T20:54:06.974103+00:00
benchmark_event event=variant_end shape=3 variant=solution ts=2026-06-14T20:54:07.005858+00:00 elapsed_s=0.032 ms=0.706592
shape=3 variant=solution tflops=680.784 gbps=273.054 ms=0.707
shape=3 solution_peak_fraction=0.6808
peak_fraction: 0.3651
RESULT: OK
assistant
The final benchmark is now at geomean peak fraction ~0.365, with the K-tail shape fixed. I’m doing a quick sanity pass over the final file for unused experimental code and forbidden strings before deciding whether to leave it as-is or trim it.
assistant
exec_command
args
{
  "cmd": "rg -n \"_scaled_mm|torch\\.ops|_fp8_gemm_wt_kernel|weight_t|weight_pad|_x_pad|@triton|def forward\" solution.py",
  "workdir": "/workspace/problems/01_fp8_gemm",
  "yield_time_ms": 1000,
  "max_output_tokens": 12000
}
assistant
exec_command
args
{
  "cmd": "sed -n '1,260p' solution.py",
  "workdir": "/workspace/problems/01_fp8_gemm",
  "yield_time_ms": 1000,
  "max_output_tokens": 30000
}
assistant
exec_command
args
{
  "cmd": "git diff -- solution.py",
  "workdir": "/workspace/problems/01_fp8_gemm",
  "yield_time_ms": 1000,
  "max_output_tokens": 30000
}
tool
stdout (1186 chars)
Chunk ID: d57dc1
Wall time: 0.0000 seconds
Process exited with code 0
Original token count: 271
Output:
10:@triton.jit
70:@triton.jit
71:def _fp8_gemm_wt_kernel(
172:        self._weight_pad = None
173:        self._weight_pad_key = None
174:        self._x_pad = None
182:    def forward(self, x: torch.Tensor) -> torch.Tensor:
192:            if self._weight_pad is None or self._weight_pad_key != w_key:
193:                weight_pad = torch.empty((self.N, k_pad), device=x.device, dtype=self.weight.dtype)
194:                weight_pad[:, : self.K].copy_(self.weight)
195:                weight_pad[:, self.K :].zero_()
196:                self._weight_pad = weight_pad
197:                self._weight_pad_key = w_key
199:                self._x_pad is None
200:                or self._x_pad.device != x.device
201:                or self._x_pad.shape != (self.M, k_pad)
203:                self._x_pad = torch.empty((self.M, k_pad), device=x.device, dtype=x.dtype)
204:            self._x_pad[:, : self.K].copy_(x)
205:            self._x_pad[:, self.K :].zero_()
206:            return _launch_fp8_gemm(self._x_pad, self._weight_pad, self.weight_scale, self.M, self.N, k_pad)
tool
stdout (6920 chars) — TRUNCATED
Chunk ID: b448ee
Wall time: 0.0000 seconds
Process exited with code 0
Original token count: 1704
Output:
import torch
import torch.nn as nn
import triton
import triton.language as tl


E4M3_MAX = 448.0


@triton.jit
def _fp8_gemm_kernel(
    x_ptr,
    w_ptr,
    scale_ptr,
    y_ptr,
    M: tl.constexpr,
    N: tl.constexpr,
    K: tl.constexpr,
    BLOCK_M: tl.constexpr,
    BLOCK_N: tl.constexpr,
    BLOCK_K: tl.constexpr,
    GROUP_M: tl.constexpr,
):
    pid = tl.program_id(0)
    num_pid_m = tl.cdiv(M, BLOCK_M)
    num_pid_n = tl.cdiv(N, BLOCK_N)
    group_size = GROUP_M * num_pid_n
    group_id = pid // group_size
    first_pid_m = group_id * GROUP_M
    group_m = tl.minimum(num_pid_m - first_pid_m, GROUP_M)
    pid_in_group = pid - group_id * group_size
    pid_m = first_pid_m + (pid_in_group % group_m)
    pid_n = pid_in_group // group_m

    offs_m = pid_m * BLOCK_M + tl.arange(0, BLOCK_M)
    offs_n = pid_n * BLOCK_N + tl.arange(0, BLOCK_N)
    offs_k = tl.arange(0, BLOCK_K)

    acc = tl.zeros((BLOCK_M, BLOCK_N), tl.float32)
    full_k = (K // BLOCK_K) * BLOCK_K
    for k0 in range(0, full_k, BLOCK_K):
        k = k0 + offs_k
        a = tl.load(x_ptr + offs_m[:, None] * K + k[None, :])
        b = tl.load(w_ptr + offs_n[None, :] * K + k[:, None])
        acc = tl.dot(a, b, acc, out_dtype=tl.float32)

    if full_k < K:
        k = full_k + offs_k
        a = tl.load(
            x_ptr + offs_m[:, None] * K + k[None, :],
            mask=k[None, :] < K,
          

... (5420 more chars)
tool
stdout (7464 chars) — TRUNCATED
Chunk ID: df97fc
Wall time: 0.0000 seconds
Process exited with code 129
Original token count: 1840
Output:
warning: Not a git repository. Use --no-index to compare two paths outside a working tree
usage: git diff --no-index [<options>] <path> <path>

Diff output format options
    -p, --patch           generate patch
    -s, --no-patch        suppress diff output
    -u                    generate patch
    -U, --unified[=<n>]   generate diffs with <n> lines context
    -W, --[no-]function-context
                          generate diffs with <n> lines context
    --raw                 generate the diff in raw format
    --patch-with-raw      synonym for '-p --raw'
    --patch-with-stat     synonym for '-p --stat'
    --numstat             machine friendly --stat
    --shortstat           output only the last line of --stat
    -X, --dirstat[=<param1,param2>...]
                          output the distribution of relative amount of changes for each sub-directory
    --cumulative          synonym for --dirstat=cumulative
    --dirstat-by-file[=<param1,param2>...]
                          synonym for --dirstat=files,param1,param2...
    --check               warn if changes introduce conflict markers or whitespace errors
    --summary             condensed summary such as creations, renames and mode changes
    --name-only           show only names of changed files
    --name-status         show only names and status of changed files
    --stat[=<width>[,<name-width>[,<count>

... (5964 more chars)
assistant
There’s one unused experimental transposed-weight kernel left in `solution.py`. I’m trimming it so the final file only contains the path that is actually benchmarked and checked.
assistant
apply_patch /workspace/problems/01_fp8_gemm/solution.py
diff (7 lines)
--- a//workspace/problems/01_fp8_gemm/solution.py
+++ b//workspace/problems/01_fp8_gemm/solution.py
@@ -1,3 +1 @@
-    if M <= 64:
-        bm, bn, bk = 32, 32, 256
-        warps, stages, group_m = 4, 4, 1
+def _launch_fp8_gemm(x: torch.Tensor, weight: torch.Tensor, weight_scale: torch.Tensor, M: int, N: int, K: int):
args
{
  "raw": "<2040 chars \u2014 see below>"
}
raw (2040 chars)
*** Begin Patch
*** Update File: /workspace/problems/01_fp8_gemm/solution.py
@@
-@triton.jit
-def _fp8_gemm_wt_kernel(
-    x_ptr,
-    wt_ptr,
-    scale_ptr,
-    y_ptr,
-    M: tl.constexpr,
-    N: tl.constexpr,
-    K: tl.constexpr,
-    BLOCK_M: tl.constexpr,
-    BLOCK_N: tl.constexpr,
-    BLOCK_K: tl.constexpr,
-    GROUP_M: tl.constexpr,
-):
-    pid = tl.program_id(0)
-    num_pid_m = tl.cdiv(M, BLOCK_M)
-    num_pid_n = tl.cdiv(N, BLOCK_N)
-    group_size = GROUP_M * num_pid_n
-    group_id = pid // group_size
-    first_pid_m = group_id * GROUP_M
-    group_m = tl.minimum(num_pid_m - first_pid_m, GROUP_M)
-    pid_in_group = pid - group_id * group_size
-    pid_m = first_pid_m + (pid_in_group % group_m)
-    pid_n = pid_in_group // group_m
-
-    offs_m = pid_m * BLOCK_M + tl.arange(0, BLOCK_M)
-    offs_n = pid_n * BLOCK_N + tl.arange(0, BLOCK_N)
-    offs_k = tl.arange(0, BLOCK_K)
-
-    acc = tl.zeros((BLOCK_M, BLOCK_N), tl.float32)
-    full_k = (K // BLOCK_K) * BLOCK_K
-    for k0 in range(0, full_k, BLOCK_K):
-        k = k0 + offs_k
-        a = tl.load(x_ptr + offs_m[:, None] * K + k[None, :])
-        b = tl.load(wt_ptr + k[:, None] * N + offs_n[None, :])
-        acc = tl.dot(a, b, acc, out_dtype=tl.float32)
-
-    if full_k < K:
-        k = full_k + offs_k
-        a = tl.load(
-            x_ptr + offs_m[:, None] * K + k[None, :],
-            mask=k[None, :] < K,
-            other=0.0,
-        )
-        b = tl.load(
-            wt_ptr + k[:, None] * N + offs_n[None, :],
-            mask=k[:, None] < K,
-            other=0.0,
-        )
-        acc = tl.dot(a, b, acc, out_dtype=tl.float32)
-
-    scales = tl.load(scale_ptr + offs_n, mask=offs_n < N, other=0.0)
-    acc = acc * scales[None, :]
-    tl.store(
-        y_ptr + offs_m[:, None] * N + offs_n[None, :],
-        acc,
-        mask=(offs_m[:, None] < M) & (offs_n[None, :] < N),
-    )
-
-
 def _launch_fp8_gemm(x: torch.Tensor, weight: torch.Tensor, weight_scale: torch.Tensor, M: int, N: int, K: int):
*** End Patch
tool
stdout (144 chars)
output:
  Success. Updated the following files:
  M /workspace/problems/01_fp8_gemm/solution.py
metadata:
  exit_code: 0
  duration_seconds: 0.0
assistant
The unused kernel is removed. I’m doing one final checker run after the cleanup; the behavior should be unchanged, but this catches accidental edits before I stop.
assistant
exec_command
args
{
  "cmd": "uv run python check.py",
  "workdir": "/workspace/problems/01_fp8_gemm",
  "yield_time_ms": 1000,
  "max_output_tokens": 20000
}
tool
stdout (112 chars)
Chunk ID: 2b79cc
Wall time: 1.0011 seconds
Process running with session ID 1810
Original token count: 0
Output:
assistant
write_stdin
args
{
  "session_id": 1810,
  "chars": "",
  "yield_time_ms": 1000,
  "max_output_tokens": 20000
}
tool
stdout (107 chars)
Chunk ID: a2b4c0
Wall time: 2.6517 seconds
Process exited with code 0
Original token count: 2
Output:
PASS
assistant
Cleanup still passes correctness. I’m taking one last benchmark reading so the final numbers correspond to the file as it now stands.
assistant
exec_command
args
{
  "cmd": "uv run python benchmark.py",
  "workdir": "/workspace/problems/01_fp8_gemm",
  "yield_time_ms": 1000,
  "max_output_tokens": 20000
}
tool
stdout (211 chars)
Chunk ID: f67507
Wall time: 1.0004 seconds
Process running with session ID 18982
Original token count: 25
Output:
benchmark_event event=variant_start shape=0 variant=solution ts=2026-06-14T20:54:53.867334+00:00
assistant
The final benchmark is running; it should be a repeat of the previous result because only dead code was removed.
assistant
write_stdin
args
{
  "session_id": 18982,
  "chars": "",
  "yield_time_ms": 1000,
  "max_output_tokens": 20000
}
tool
stdout (1320 chars)
Chunk ID: efb884
Wall time: 0.0000 seconds
Process exited with code 0
Original token count: 304
Output:
benchmark_event event=variant_end shape=0 variant=solution ts=2026-06-14T20:54:54.074914+00:00 elapsed_s=0.208 ms=0.221120
shape=0 variant=solution tflops=621.558 gbps=303.495 ms=0.221
shape=0 solution_peak_fraction=0.6216
benchmark_event event=variant_start shape=1 variant=solution ts=2026-06-14T20:54:54.584204+00:00
benchmark_event event=variant_end shape=1 variant=solution ts=2026-06-14T20:54:54.600883+00:00 elapsed_s=0.017 ms=0.244800
shape=1 variant=solution tflops=565.683 gbps=275.175 ms=0.245
shape=1 solution_peak_fraction=0.5657
benchmark_event event=variant_start shape=2 variant=solution ts=2026-06-14T20:54:56.440040+00:00
benchmark_event event=variant_end shape=2 variant=solution ts=2026-06-14T20:54:56.445560+00:00 elapsed_s=0.006 ms=0.058448
shape=2 variant=solution tflops=73.484 gbps=1161.636 ms=0.058
shape=2 solution_peak_fraction=0.0735
benchmark_event event=variant_start shape=3 variant=solution ts=2026-06-14T20:54:58.109524+00:00
benchmark_event event=variant_end shape=3 variant=solution ts=2026-06-14T20:54:58.141242+00:00 elapsed_s=0.032 ms=0.708128
shape=3 variant=solution tflops=679.307 gbps=272.462 ms=0.708
shape=3 solution_peak_fraction=0.6793
peak_fraction: 0.3640
RESULT: OK
assistant
Final benchmark completed with `RESULT: OK` and peak_fraction about 0.364. I’m doing a quick source grep for forbidden calls and interface names, then I’ll summarize the result.
assistant
exec_command
args
{
  "cmd": "rg -n \"torch\\._scaled_mm|torch\\.ops\\.aten\\._scaled_mm|class Model|def get_inputs|def get_init_inputs|register_buffer|tl\\.dot\" solution.py",
  "workdir": "/workspace/problems/01_fp8_gemm",
  "yield_time_ms": 1000,
  "max_output_tokens": 8000
}
assistant
exec_command
args
{
  "cmd": "sed -n '1,220p' solution.py",
  "workdir": "/workspace/problems/01_fp8_gemm",
  "yield_time_ms": 1000,
  "max_output_tokens": 22000
}
assistant
exec_command
args
{
  "cmd": "ls -1",
  "workdir": "/workspace/problems/01_fp8_gemm",
  "yield_time_ms": 1000,
  "max_output_tokens": 4000
}
tool
stdout (425 chars)
Chunk ID: bdab2a
Wall time: 0.0000 seconds
Process exited with code 0
Original token count: 81
Output:
45:        acc = tl.dot(a, b, acc, out_dtype=tl.float32)
59:        acc = tl.dot(a, b, acc, out_dtype=tl.float32)
108:class Model(nn.Module):
119:        self.register_buffer("weight", w_fp8)
120:        self.register_buffer("weight_scale", s.squeeze(1).to(torch.float32))
155:def get_inputs():
160:def get_init_inputs():
tool
stdout (5148 chars) — TRUNCATED
Chunk ID: 9d30fc
Wall time: 0.0000 seconds
Process exited with code 0
Original token count: 1261
Output:
import torch
import torch.nn as nn
import triton
import triton.language as tl


E4M3_MAX = 448.0


@triton.jit
def _fp8_gemm_kernel(
    x_ptr,
    w_ptr,
    scale_ptr,
    y_ptr,
    M: tl.constexpr,
    N: tl.constexpr,
    K: tl.constexpr,
    BLOCK_M: tl.constexpr,
    BLOCK_N: tl.constexpr,
    BLOCK_K: tl.constexpr,
    GROUP_M: tl.constexpr,
):
    pid = tl.program_id(0)
    num_pid_m = tl.cdiv(M, BLOCK_M)
    num_pid_n = tl.cdiv(N, BLOCK_N)
    group_size = GROUP_M * num_pid_n
    group_id = pid // group_size
    first_pid_m = group_id * GROUP_M
    group_m = tl.minimum(num_pid_m - first_pid_m, GROUP_M)
    pid_in_group = pid - group_id * group_size
    pid_m = first_pid_m + (pid_in_group % group_m)
    pid_n = pid_in_group // group_m

    offs_m = pid_m * BLOCK_M + tl.arange(0, BLOCK_M)
    offs_n = pid_n * BLOCK_N + tl.arange(0, BLOCK_N)
    offs_k = tl.arange(0, BLOCK_K)

    acc = tl.zeros((BLOCK_M, BLOCK_N), tl.float32)
    full_k = (K // BLOCK_K) * BLOCK_K
    for k0 in range(0, full_k, BLOCK_K):
        k = k0 + offs_k
        a = tl.load(x_ptr + offs_m[:, None] * K + k[None, :])
        b = tl.load(w_ptr + offs_n[None, :] * K + k[:, None])
        acc = tl.dot(a, b, acc, out_dtype=tl.float32)

    if full_k < K:
        k = full_k + offs_k
        a = tl.load(
            x_ptr + offs_m[:, None] * K + k[None, :],
            mask=k[None, :] < K,
          

... (3648 more chars)
tool
stdout (218 chars)
Chunk ID: 7bc984
Wall time: 0.0000 seconds
Process exited with code 0
Original token count: 29
Output:
PROMPT.txt
__pycache__
benchmark.py
check.py
framework.txt
problem.yaml
reference.py
shapes.py
solution.py
sota.py
assistant
Implemented the FP8 GEMM in [solution.py](/workspace/problems/01_fp8_gemm/solution.py). What changed: - Added a Triton `tl.dot` FP8 x FP8 tensor-core kernel with fp32 accumulation and fused per-channel `weight_scale`. - Tuned separate tile configs for square, odd-K, skinny-M, and wide-N shapes. - Added a dedicated odd-K path that pads K=4127 to 4224, caches the padded weight, pads activation each forward, then runs the faster aligned FP8 kernel. - Preserved the required `Model`, `get_inputs`, and `get_init_inputs` interfaces and registered `weight` / `weight_scale`. Verification: - `uv run python check.py` -> `PASS` - `uv run python benchmark.py` -> `RESULT: OK`, `peak_fraction: 0.3640` Latest benchmark: - shape 0: `621.558 TFLOP/s`, `0.221 ms` - shape 1: `565.683 TFLOP/s`, `0.245 ms` - shape 2: `73.484 TFLOP/s`, `0.058 ms` - shape 3: `679.307 TFLOP/s`, `0.708 ms`
system
task_complete