solution.py
final answer
benchmark.log
check.log
result.json
from __future__ import annotations
import torch
import torch.nn as nn
import triton
import triton.language as tl
@triton.jit
def _state_kernel(
kg,
w,
u,
g,
hbuf,
vnew,
T: tl.constexpr,
H: tl.constexpr,
NT: tl.constexpr,
K: tl.constexpr,
V: tl.constexpr,
BT: tl.constexpr,
BV: tl.constexpr,
):
pid_v = tl.program_id(0)
pid_bh = tl.program_id(1)
b = pid_bh // H
hidx = pid_bh - b * H
offs_v = pid_v * BV + tl.arange(0, BV)
offs_c = tl.arange(0, BT)
offs_k = tl.arange(0, 64)
mask_v = offs_v < V
s0 = tl.zeros((64, BV), dtype=tl.float32)
s1 = tl.zeros((64, BV), dtype=tl.float32)
for n in range(0, NT):
h_base = (((b * NT + n) * H + hidx) * K) * V
tl.store(
hbuf + h_base + offs_k[:, None] * V + offs_v[None, :],
s0.to(hbuf.dtype.element_ty),
mask=mask_v[None, :],
)
tl.store(
hbuf + h_base + (offs_k[:, None] + 64) * V + offs_v[None, :],
s1.to(hbuf.dtype.element_ty),
mask=mask_v[None, :],
)
t = n * BT + offs_c
w_base = ((b * T + t[:, None]) * H + hidx) * K
w0 = tl.load(w + w_base + offs_k[None, :])
w1 = tl.load(w + w_base + offs_k[None, :] + 64)
projected = tl.dot(w0, s0.to(w0.dtype)) + tl.dot(w1, s1.to(w1.dtype))
uv_base = ((b * T + t[:, None]) * H + hidx) * V
u_block = tl.load(u + uv_base + offs_v[None, :], mask=mask_v[None, :], other=0.0)
vn = u_block.to(tl.float32) - projected
tl.store(
vnew + uv_base + offs_v[None, :],
vn.to(vnew.dtype.element_ty),
mask=mask_v[None, :],
)
last_t = n * BT + BT - 1
g_base = ((b * T + last_t) * H + hidx) * K
g0 = tl.load(g + g_base + offs_k).to(tl.float32)
g1 = tl.load(g + g_base + offs_k + 64).to(tl.float32)
s0 *= tl.exp(g0)[:, None]
s1 *= tl.exp(g1)[:, None]
kg_base = ((b * T + t[:, None]) * H + hidx) * K
kg0 = tl.load(kg + kg_base + offs_k[None, :])
kg1 = tl.load(kg + kg_base + offs_k[None, :] + 64)
vn_tc = vn.to(kg0.dtype)
s0 += tl.dot(tl.trans(kg0), vn_tc)
s1 += tl.dot(tl.trans(kg1), vn_tc)
@triton.jit
def _out_kernel(
q,
g,
amat,
hbuf,
vnew,
out,
scale: tl.constexpr,
T: tl.constexpr,
H: tl.constexpr,
NT: tl.constexpr,
K: tl.constexpr,
V: tl.constexpr,
BT: tl.constexpr,
BV: tl.constexpr,
):
pid_v = tl.program_id(0)
n = tl.program_id(1)
pid_bh = tl.program_id(2)
b = pid_bh // H
hidx = pid_bh - b * H
offs_v = pid_v * BV + tl.arange(0, BV)
offs_c = tl.arange(0, BT)
offs_k = tl.arange(0, 64)
mask_v = offs_v < V
t = n * BT + offs_c
qg_base = ((b * T + t[:, None]) * H + hidx) * K
q0 = tl.load(q + qg_base + offs_k[None, :])
q1 = tl.load(q + qg_base + offs_k[None, :] + 64)
g0 = tl.load(g + qg_base + offs_k[None, :]).to(tl.float32)
g1 = tl.load(g + qg_base + offs_k[None, :] + 64).to(tl.float32)
q0 = (q0 * tl.exp(g0)).to(q0.dtype)
q1 = (q1 * tl.exp(g1)).to(q1.dtype)
h_base = (((b * NT + n) * H + hidx) * K) * V
hs0 = tl.load(
hbuf + h_base + offs_k[:, None] * V + offs_v[None, :],
mask=mask_v[None, :],
other=0.0,
)
hs1 = tl.load(
hbuf + h_base + (offs_k[:, None] + 64) * V + offs_v[None, :],
mask=mask_v[None, :],
other=0.0,
)
acc = tl.dot(q0, hs0) + tl.dot(q1, hs1)
acc *= scale
a_base = ((b * T + t[:, None]) * H + hidx) * BT
a = tl.load(amat + a_base + offs_c[None, :])
uv_base = ((b * T + t[:, None]) * H + hidx) * V
vn = tl.load(vnew + uv_base + offs_v[None, :], mask=mask_v[None, :], other=0.0)
acc += tl.dot(a, vn)
tl.store(
out + uv_base + offs_v[None, :],
acc.to(out.dtype.element_ty),
mask=mask_v[None, :],
)
def _forward_impl(
q: torch.Tensor,
k: torch.Tensor,
v: torch.Tensor,
g: torch.Tensor,
beta: torch.Tensor,
scale: float,
chunk_size: int,
) -> torch.Tensor:
dtype = v.dtype
B, T, H, K = q.shape
V = v.shape[-1]
BT = chunk_size
NT = T // BT
if K != 128 or V != 128 or BT != 64:
raise RuntimeError("this kernel is specialized for K=V=128 and chunk_size=64")
gf = g.float()
bf = beta.float()
q_bhnck = q.view(B, NT, BT, H, K).permute(0, 3, 1, 2, 4).contiguous()
k_bhnck = k.view(B, NT, BT, H, K).permute(0, 3, 1, 2, 4).contiguous()
v_bhncv = v.view(B, NT, BT, H, V).permute(0, 3, 1, 2, 4).contiguous()
g_bhnck = (
gf.view(B, NT, BT, H, K)
.permute(0, 3, 1, 2, 4)
.contiguous()
.cumsum(-2)
)
b_bhnc = bf.view(B, NT, BT, H).permute(0, 3, 1, 2).contiguous()
flat = B * H * NT
tc_setup = T >= 2048 and B * H >= 8
k_flat_raw = k_bhnck.reshape(flat, BT, K)
g_flat = g_bhnck.reshape(flat, BT, K)
v_flat_raw = v_bhncv.reshape(flat, BT, V)
beta_flat = b_bhnc.reshape(flat, BT)
eg = g_flat.exp()
if tc_setup:
kg_exp = (k_flat_raw.float() * eg).to(dtype)
kg_inv = (k_flat_raw.float() * (-g_flat).exp()).to(dtype)
v_flat = v_flat_raw
kk = torch.bmm(kg_exp, kg_inv.transpose(1, 2)).float()
else:
k_flat = k_flat_raw.float()
v_flat = v_flat_raw.float()
kg_exp = k_flat * eg
kg_inv = k_flat * (-g_flat).exp()
kk = torch.bmm(kg_exp, kg_inv.transpose(1, 2))
lower_strict = torch.tril(
torch.ones(BT, BT, dtype=torch.bool, device=q.device),
diagonal=-1,
)
lmat = (-kk * beta_flat[:, :, None]).masked_fill(~lower_strict, 0.0)
eye = torch.eye(BT, dtype=torch.float32, device=q.device)
rhs = torch.diag_embed(beta_flat)
amat_full = torch.linalg.solve_triangular(
eye.expand(flat, BT, BT) - lmat,
rhs,
upper=False,
unitriangular=True,
)
if tc_setup:
amat_mm = amat_full.to(dtype)
w = torch.bmm(amat_mm, kg_exp)
u = torch.bmm(amat_mm, v_flat)
else:
w = torch.bmm(amat_full, kg_exp)
u = torch.bmm(amat_full, v_flat)
q_scaled = (q_bhnck.float() * scale).reshape(flat, BT, K)
if tc_setup:
aqk = torch.bmm((q_scaled * eg).to(dtype), kg_inv.transpose(1, 2)).float()
else:
aqk = torch.bmm(q_scaled * eg, kg_inv.transpose(1, 2))
lower = torch.tril(torch.ones(BT, BT, dtype=torch.bool, device=q.device))
aqk = aqk.masked_fill(~lower, 0.0)
w_bthk = (
w.reshape(B, H, NT, BT, K)
.permute(0, 2, 3, 1, 4)
.reshape(B, T, H, K)
.contiguous()
.to(dtype)
)
u_bthv = (
u.reshape(B, H, NT, BT, V)
.permute(0, 2, 3, 1, 4)
.reshape(B, T, H, V)
.contiguous()
.to(dtype)
)
aqk_bthc = (
aqk.reshape(B, H, NT, BT, BT)
.permute(0, 2, 3, 1, 4)
.reshape(B, T, H, BT)
.contiguous()
.to(dtype)
)
g_last = g_bhnck[:, :, :, -1:, :]
kg_state = (
(k_bhnck.float() * (g_last - g_bhnck).exp())
.permute(0, 2, 3, 1, 4)
.reshape(B, T, H, K)
.contiguous()
.to(dtype)
)
g_bthk = (
g_bhnck.permute(0, 2, 3, 1, 4)
.reshape(B, T, H, K)
.contiguous()
)
hbuf = torch.empty((B, NT, H, K, V), device=q.device, dtype=dtype)
vnew = torch.empty_like(v)
out = torch.empty_like(v)
grid_state = (triton.cdiv(V, 64), B * H)
_state_kernel[grid_state](
kg_state,
w_bthk,
u_bthv,
g_bthk,
hbuf,
vnew,
T,
H,
NT,
K,
V,
BT,
BV=64,
num_warps=4,
num_stages=3,
)
grid_out = (triton.cdiv(V, 64), NT, B * H)
_out_kernel[grid_out](
q,
g_bthk,
aqk_bthc,
hbuf,
vnew,
out,
scale,
T,
H,
NT,
K,
V,
BT,
BV=64,
num_warps=4,
num_stages=3,
)
return out
class Model(nn.Module):
def __init__(self, B: int, T: int, H: int, K: int, V: int, chunk_size: int = 64):
super().__init__()
self.B, self.T, self.H, self.K, self.V = B, T, H, K, V
self.chunk_size = chunk_size
self.scale = float(K) ** -0.5
self.register_buffer("_dummy", torch.zeros(1), persistent=False)
def forward(
self,
q: torch.Tensor,
k: torch.Tensor,
v: torch.Tensor,
g: torch.Tensor,
beta: torch.Tensor,
) -> torch.Tensor:
return _forward_impl(q, k, v, g, beta, self.scale, self.chunk_size)
B = 2
T = 1024
H = 8
K = 128
V = 128
CHUNK_SIZE = 64
def get_inputs():
torch.manual_seed(0)
q = torch.randn(B, T, H, K, dtype=torch.bfloat16) * 0.1
k = torch.randn(B, T, H, K, dtype=torch.bfloat16) * 0.1
v = torch.randn(B, T, H, V, dtype=torch.bfloat16) * 0.1
g = torch.randn(B, T, H, K, dtype=torch.float32) * 0.1 - 0.05
beta = torch.sigmoid(torch.randn(B, T, H, dtype=torch.bfloat16))
return [q, k, v, g, beta]
def get_init_inputs():
return [B, T, H, K, V, CHUNK_SIZE]
Implemented KDA forward in [solution.py](/home/infatoshi/cuda/KernelBench-Hard/problems/02_kda_cutlass/solution.py:1). The submitted path uses two specialized Triton kernels: `_state_kernel` for the inter-chunk delta-state recurrence and `_out_kernel` for the final `qg @ state + A @ v_new` output block. The per-chunk triangular factors are built directly from the reference algebra with batched products plus the unit lower-triangular solve, including the in-chunk `g.cumsum(-2)` behavior from `reference.py`.
I also added [test_solution.py](/home/infatoshi/cuda/KernelBench-Hard/problems/02_kda_cutlass/test_solution.py:1) so `uv run pytest` executes the official `check.py` correctness sweep instead of collecting zero tests.
Verification completed:
```text
uv run check.py
PASS
uv run ruff check . --fix
All checks passed!
uv run pytest
1 passed in 3.56s
```
Final `uv run benchmark.py` solution timings:
```text
shape=0 solution: 0.305 ms, 7.046 TFLOPS, peak_fraction=0.0352
shape=1 solution: 0.483 ms, 8.883 TFLOPS, peak_fraction=0.0444
shape=2 solution: 0.534 ms, 8.046 TFLOPS, peak_fraction=0.0402
shape=3 solution: 0.327 ms, 3.279 TFLOPS, peak_fraction=0.0164
peak_fraction: 0.0319
RESULT: LOW
```
The full benchmark still reports `LOW` because its OK threshold is `0.1` of the advertised 200 TFLOP/s dense bf16 peak, but the solution is within range of the installed SOTA line on the short and thin cases and about 1.7x slower on the two long full-head cases.
shape=0 variant=eager tflops=0.061 gbps=0.714 ms=35.270
shape=0 variant=compiled tflops=0.510 gbps=5.987 ms=4.209
shape=0 variant=sota tflops=8.439 gbps=99.026 ms=0.254
shape=0 variant=solution tflops=7.105 gbps=83.368 ms=0.302
shape=0 solution_peak_fraction=0.0355
shape=1 variant=eager tflops=0.064 gbps=0.748 ms=67.368
shape=1 variant=compiled tflops=0.492 gbps=5.769 ms=8.735
shape=1 variant=sota tflops=15.544 gbps=182.398 ms=0.276
shape=1 variant=solution tflops=8.893 gbps=104.347 ms=0.483
shape=1 solution_peak_fraction=0.0445
shape=2 variant=eager tflops=0.041 gbps=0.478 ms=105.331
shape=2 variant=compiled tflops=0.266 gbps=3.122 ms=16.142
shape=2 variant=sota tflops=13.824 gbps=162.212 ms=0.311
shape=2 variant=solution tflops=8.042 gbps=94.360 ms=0.534
shape=2 solution_peak_fraction=0.0402
shape=3 variant=eager tflops=0.020 gbps=0.230 ms=54.776
shape=3 variant=compiled tflops=0.212 gbps=2.483 ms=5.074
shape=3 variant=sota tflops=4.044 gbps=47.457 ms=0.265
shape=3 variant=solution tflops=3.318 gbps=38.935 ms=0.324
shape=3 solution_peak_fraction=0.0166
peak_fraction: 0.0320
RESULT: LOW
{
"problem": "02_kda_cutlass",
"harness": "codex",
"model": "gpt-5.5",
"reasoning_effort": "xhigh",
"has_solution": true,
"correct": true,
"peak_fraction": 0.0320,
"elapsed_seconds": 1534,
"harness_exit_code": 0,
"session_complete": true,
"usage": {"input_tokens": 5176087, "output_tokens": 34921, "cache_read_tokens": 5035136, "cache_creation_tokens": null, "reasoning_tokens": 16326, "total_cost_usd": null}
}
timeline (223 events)
system
session start model=None ctx=?
system
task_started turn=019dd28a
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/infatoshi/.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/infatoshi/.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/infatoshi/.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/infatoshi/.codex/skills/.system/skill-creator/SKILL.md)
- skill-installer: Install Codex skills into $CODEX_HOME/skills from a curated list or a GitHub repo path. Use when a user asks to list installable skills, install a curated skill, or install a skill from another repo (including private repos). (file: /home/infatoshi/.codex/skills/.system/skill-installer/SKILL.md)
### How to use skills
- Discovery: The list above is the skills available in this session (name + description + file path). Skill bodies live on disk at the listed paths.
- Trigger rules: If the user names a skill (with `$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
# AGENTS.md instructions for /home/infatoshi/cuda/KernelBench-Hard/problems/02_kda_cutlass
<INSTRUCTIONS>
# Global Agent Instructions
## Python
UV is the ONLY way to run Python. No exceptions.
- `uv run script.py` (not `python script.py`)
- `uv pip install` / `uv add` (not `pip install`)
- `uv venv` (not `python -m venv`)
Never use `--system`. Never use bare `python`/`pip` commands.
## Testing
Tests are MANDATORY for all implementation work.
- Run tests: `uv run pytest`
- Run linting: `uv run ruff check . --fix`
- Both must pass before work is complete
Comparison rules:
- Integers/exact: bitwise comparison (`==`)
- Floats: `atol`/`rtol` tolerance (IEEE 754 limitations)
## Restrictions
- No emojis in code or comments
- No em dashes
- Never guess performance numbers - benchmark or say "needs measurement"
- Do not over-engineer - minimal changes only
- Do not add features beyond what was requested
- Do not refactor unrelated code
## Verification Protocol
Before completing ANY task:
1. Re-read the original request. Does your work fully address it? Not partially -- fully.
2. If you wrote or modified code, execute it. Verify the output matches expectations.
3. If tests exist, run them. If you made non-trivial changes and no tests exist, write them.
4. Review your last several tool outputs for unaddressed errors, warnings, or failures.
5. If you edited a file 10+ times without resolving the issue, stop and try a fundamentally different approach.
Do NOT declare completion until all checks pass.
## Environment Discovery
At the start of complex tasks, map the environment:
- Check what's installed (uv, python version, key packages)
- Check git state (branch, dirty files, recent commits)
- Check disk space if doing large builds
- Read SPEC.md if it exists
## GPU (Shared Machine)
Before running ANY GPU workload (training, inference, profiling, benchmarking, kernel compilation),
check `nvidia-smi` to verify GPU utilization is low enough to proceed. Multiple people share
this machine. If the GPU is already in use (>10% utilization or significant memory allocated),
do NOT launch your workload -- report the conflict and wait for instructions.
## Machines
- local/macbook: MacBook Pro M4 Max (14c: 10P+4E), 36GB unified, Metal 3, macOS 26.3
- anvil: Ryzen 9 9950X3D (16c/32t), 92GB DDR5, RTX PRO 6000 Blackwell Workstation 96GB (sm_120, 600W TDP), 3.6TB NVMe, Ubuntu 24.04, CUDA 13.2 + nvcc 12.8, Driver 595.58.03 (hostname: anvil, formerly theodolos)
## Google CLI (gogcli)
Binary at /usr/local/bin/gog. Keyring password in $GOG_KEYRING_PASSWORD.
Accounts (use -a flag to select):
infatoshi@gmail.com -- personal. Gumroad sales, subscriptions, personal contacts, Google Drive storage.
elliot@arledge.net -- professional. Manning book (CUDA for DL), contracts, invoices, GitHub, work correspondence.
Drive:
gog ls -a EMAIL [--parent FOLDER_ID] [--max N]
gog drive search -a EMAIL "query" [--raw-query "Drive query language"]
gog drive mkdir "name" -a EMAIL [--parent FOLDER_ID]
gog drive move FILE_ID -a EMAIL --parent FOLDER_ID
gog drive delete FILE_ID -a EMAIL -y
gog download FILE_ID -a EMAIL [-o output_path]
gog upload LOCAL_PATH -a EMAIL [--parent FOLDER_ID]
Gmail:
gog gmail search -a EMAIL "gmail query syntax" [--max N]
gog gmail messages read MSG_ID -a EMAIL
gog send -a EMAIL --to ADDR --subject "subj" --body "text"
Calendar:
gog calendar events -a EMAIL [--max N]
gog calendar create CALENDAR_ID -a EMAIL --summary "title" --start "2026-01-01T09:00:00" --end "2026-01-01T10:00:00"
For formatted emails use --body-html with HTML, not markdown in --body. Use --help on any subcommand for full flags.
## browser-use (deterministic CLI, no LLM keys)
Installed via pipx at ~/.local/bin/browser-use (Python 3.12). Claude/agents drive it directly
by reading `state` (a11y tree) or `screenshot` PNGs, then firing primitive actions. No API keys
are configured -- do NOT run `browser-use setup` or use `extract`/agent mode.
Primitives:
browser-use open <url> [--headed]
browser-use state # a11y tree with [index]<tag /> refs
browser-use screenshot /path.png # --full for full page
browser-use click <index>
browser-use type "text" # into focused field
browser-use input <index> "text" # into specific element
browser-use scroll down|up
browser-use keys Enter|Tab|...
browser-use eval "js expr"
browser-use back | hover | select | upload | cookies | wait
browser-use close # kill daemon session
Session is a persistent daemon -- always `close` when done.
Anvil: IN_DOCKER=true is set in ~/.zshenv (AppArmor blocks Chrome's user-namespace sandbox on
Ubuntu 24.04; IN_DOCKER=true makes browser-use launch Chromium with --no-sandbox).
## X/Twitter CLI (x-cli)
CLI at ~/.local/bin/x-cli. Credentials in ~/x-cli/.env.
x-cli user timeline USERNAME --max N # fetch recent posts
x-cli user get USERNAME # profile lookup
x-cli tweet search "query" --max N # search tweets
x-cli tweet post "text" # post a tweet
x-cli tweet reply TWEET_ID "text" # reply to a tweet
x-cli me mentions --max N # your mentions
x-cli like TWEET_ID # like a tweet
Add -j for JSON, -md for markdown, -p for TSV. Use --help on any subcommand.
## alphaxiv CLI (no auth)
Arxiv paper lookup at ~/.cargo/bin/alphaxiv (sigkillme0/alphaxiv-cli, Rust).
Aggregates alphaxiv.org + Semantic Scholar + HuggingFace + OpenAlex + arxiv.
alphaxiv paper <ID|URL|DOI> # full dossier: abstract, HF models/datasets, comments
alphaxiv read <ID> # full parsed text from arxiv HTML
alphaxiv download <ID> -o X # PDF to path
alphaxiv search "query" # keyword search
alphaxiv feed # trending
alphaxiv new <category> # latest in cs.LG, cs.CL, etc.
alphaxiv refs <ID> | cites <ID> | related <ID> | similar <ID>
alphaxiv author "Name" # h-index, top papers
Flags: --json, --ids (pipe-friendly), --raw. Note: `batch` panics in v0.5.4, skip it.
## Project Context Files
When creating or updating project-level CLAUDE.md or AGENTS.md files:
**Include:** version pins, build/run/test commands, behavioral overrides,
undiscoverable context (company/hardware/API configs), current status,
domain gotchas, hard constraints the model gets wrong without being told.
**Exclude:** directory trees (discoverable), architecture narration,
feature specs (use SPEC.md), enum/type definitions from code,
workflow docs, general coding principles, anything findable in <60s.
If something keeps breaking or you hit the same mistake twice, add the fix
to the project AGENTS.md/CLAUDE.md so future sessions don't repeat it.
Fewer constraints with higher signal beats comprehensive documentation.
--- project-doc ---
# KernelBench-Hard — Developer Instructions (codex / droid)
This is the codex / droid / cursor-agent equivalent of `CLAUDE.md`. Content is identical; format is plain markdown for any CLI.
See [`CLAUDE.md`](./CLAUDE.md) for the canonical version. All rules there apply.
Summary of the non-negotiables:
- **uv only.** `uv run ...`, `uv add ...`, `uv pip install ...`. Never `pip` or bare `python`.
- **Before committing:** `uv run ruff check . --fix && uv run pytest`.
- **Do not edit `problems/*/solution.py`** — those are agent output.
- **Do not modify `reference.py`, `check.py`, `benchmark.py`, `problem.yaml`, `shapes.py`, or `PROMPT.txt`** of an already-published problem.
- **Apply the torch 2.11 inductor CSE hotfix** via `./scripts/patch_torch.sh` after any `uv sync`.
## Quick actions
```bash
uv sync
./scripts/patch_torch.sh
./scripts/run_hard.sh claude claude-opus-4-7 problems/01_fp8_gemm
```
## Repo layout and adding a new problem
See `CLAUDE.md` — everything there is authoritative.
</INSTRUCTIONS>
<environment_context>
<cwd>/home/infatoshi/cuda/KernelBench-Hard/problems/02_kda_cutlass</cwd>
<shell>zsh</shell>
<current_date>2026-04-27</current_date>
<timezone>America/Edmonton</timezone>
</environment_context>
user
I need you to implement Kimi Delta Attention forward (chunk form) 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.
The op is the chunk-parallel KDA forward from the FLA library: q and k of shape (B, T, H, K) in bf16, v of shape (B, T, H, V) in bf16, g of shape (B, T, H, K) in fp32 (per-channel log-decay with in-chunk cumsum already applied), beta of shape (B, T, H) in bf16, scale a python float, chunk_size 64, no initial state, no final state. You return o of shape (B, T, H, V) in bf16. Correctness tolerance is 0.05 abs/rel — the long recurrence accumulates more error than a single GEMM so the bar's a bit looser than default bf16. The shapes you have to handle are B=2 T=1024 H=8 K=128 V=128 (short-context training step), B=2 T=2048 H=8 K=128 V=128 (the headline shape from the Kimi Linear paper), B=1 T=4096 H=8 K=128 V=128 (long context that stresses the inter-chunk recurrence), and B=1 T=2048 H=4 K=128 V=128 (thin batch decode).
This needs to be a real custom kernel — the whole point of the problem is to write the chunk-parallel attention yourself, not call FLA's existing implementation. Don't import or call fla.ops.kda, fla.ops.chunk_kda, chunk_kda, fused_recurrent_kda, naive_chunk_kda, or naive_recurrent_kda. The intended path is CUTLASS CuTe on SM120 but Triton, CUDA C++ via load_inline, or inline PTX are also fine if you prefer. Anything you're uncertain about, look up PTX docs, clone CUTLASS or FLA 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.
assistant
reasoning (425 chars)
**Evaluating UV commands**
I’m considering whether `uv run python -c` is acceptable. I read that UV is the preferred way to run Python, with examples showing `uv run script.py`. They recommend against using bare python/pip commands. So it seems maybe `uv run python -c` is fine since it runs Python through UV. However, it might be better to use `uv run - <<'PY'` for implicitly executing Python. I’ll check to confirm this!
assistant
I’ll first map the local problem and harness so the kernel matches the exact interface and validation path. I’ll also check GPU availability before compiling or running anything CUDA-heavy, since this is a shared machine.
tool
stdout (242 chars)
Chunk ID: f945b6
Wall time: 0.0000 seconds
Process exited with code 0
Original token count: 35
Output:
/home/infatoshi/cuda/KernelBench-Hard/problems/02_kda_cutlass
PROMPT.txt
shapes.py
sota.py
reference.py
check.py
benchmark.py
problem.yaml
tool
stdout (338 chars)
Chunk ID: 666656
Wall time: 0.0000 seconds
Process exited with code 0
Original token count: 59
Output:
## master...origin/master
96b597e qwen3.6-27b reinstated: 1/7 PASS in post-fix rerun
5722a4a opencode workspace leak: deny external_directory + drop qwen3.6-27b
50ecc7a Shakedown sweep results + drop qwen3.6-35b-a3b from active matrix
tool
stdout (244 chars)
Chunk ID: 140fc7
Wall time: 0.0000 seconds
Process exited with code 0
Original token count: 36
Output:
Filesystem Size Used Avail Use% Mounted on
/dev/nvme0n1p2 3.6T 1.8T 1.7T 51% /
uv 0.11.3 (x86_64-unknown-linux-gnu)
Python 3.11.15
tool
stdout (168 chars)
Chunk ID: c0bb59
Wall time: 0.0000 seconds
Process exited with code 0
Original token count: 17
Output:
NVIDIA RTX PRO 6000 Blackwell Workstation Edition, 0, 508, 97887
assistant
reasoning (405 chars)
**Inspecting files for GPU use**
I see that the GPU is at 0% utilization and has a capacity of 508/97GB, so I need to check some files. I should look into `reference.py` for benchmarking and structure. Maybe I'll utilize some parallel commands like `cat` and `sed` to help with the inspection. This process seems straightforward, but I hope I don’t overlook anything critical as I go through these files!
assistant
GPU is idle enough to proceed: 0% utilization and about 0.5 GB allocated. I’m reading the reference, harness, and shape definitions next so the implementation targets the real validator rather than a hand-rolled check.
tool
stdout (5198 chars) — TRUNCATED
Chunk ID: 13cb6d
Wall time: 0.0000 seconds
Process exited with code 0
Original token count: 1274
Output:
"""Naive PyTorch reference for Kimi Delta Attention (KDA) forward, chunk form.
This is the correctness oracle, NOT the SOTA baseline. It mirrors the
chunk-parallel formulation in fla/ops/kda/naive.py (Songlin Yang et al.)
without any Triton or CUDA optimization.
Inputs (per the FLA convention):
q, k : (B, T, H, K) bf16 -- queries / keys
v : (B, T, H, V) bf16 -- values
g : (B, T, H, K) fp32 -- per-channel log-decay (in-chunk cumsum applied)
beta : (B, T, H) bf16 -- write strength
Output:
o : (B, T, H, V) bf16
The agent must reproduce this output (within bf16 tolerance) using a CUTLASS
CuTe kernel on SM120 -- NOT by calling fla.ops.chunk_kda directly.
"""
from __future__ import annotations
import torch
import torch.nn as nn
from einops import rearrange
OP_TYPE = "linear_attention"
SUPPORTED_PRECISIONS = ["bf16"]
HARDWARE_REQUIRED = ["RTX_PRO_6000", "H100", "B200"]
def _naive_chunk_kda(
q: torch.Tensor,
k: torch.Tensor,
v: torch.Tensor,
g: torch.Tensor,
beta: torch.Tensor,
scale: float,
chunk_size: int = 64,
) -> torch.Tensor:
"""KDA forward, no initial state, no final state. Returns o with v's dtype."""
dtype = v.dtype
B, T, H, K = q.shape
V = v.shape[-1]
BT = chunk_size
assert T % BT == 0, f"T={T} must be a multiple of chunk_size={BT}"
NT = T // BT
q, k, v, g, beta =
... (3698 more chars)
tool
stdout (3926 chars) — TRUNCATED
Chunk ID: 26661b
Wall time: 0.0000 seconds
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Output:
"""Correctness runner for KDA forward (chunk form).
Runs solution.Model vs reference.Model across all shapes in shapes.py, 3 seeds
each, with per-dtype atol/rtol (bf16 default 1e-2 plus a 5e-2 override for
this problem). 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
def _apply_shape(reference, shape):
"""Override reference's module-level shape shims so get_inputs/get_init_inputs match."""
for k, v in shape.items():
setattr(reference, k, v)
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)
de
... (2426 more chars)
tool
stdout (4485 chars) — TRUNCATED
Chunk ID: 925ff9
Wall time: 0.0000 seconds
Process exited with code 0
Original token count: 1095
Output:
"""Roofline benchmark for KDA forward (chunk form).
For each shape: times eager reference, compiled reference, SOTA (FLA's Triton
chunk_kda, if available on this GPU), and the agent's solution. 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 time_fn # noqa: E402
from src.hardware import get as get_hw # noqa: E402
def _eval_formula(expr: str, vars: dict) -> float:
return float(eval(expr, {"__builtins__": {}}, vars))
def _apply_shape(reference, shape):
for k, v in shape.items():
setattr(reference, k, v)
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_formul
... (2985 more chars)
tool
stdout (5492 chars) — TRUNCATED
Chunk ID: 7f1f8b
Wall time: 0.0000 seconds
Process exited with code 0
Original token count: 1347
Output:
"""Canonical shape sweep for KDA forward (chunk form).
Mix of:
- short-context training-step scale (T=1024)
- mid-context (T=2048) which is the headline benchmark
- long-context that stresses the inter-chunk recurrence (T=4096)
- thin-batch decode-style (B=1, T=2048, fewer heads)
Constraints:
- T % chunk_size == 0 (chunk_size = 64)
- K, V are the per-head channel dims; KDA in Kimi Linear uses K=V=128
"""
SHAPES = [
{"B": 2, "T": 1024, "H": 8, "K": 128, "V": 128, "CHUNK_SIZE": 64},
{"B": 2, "T": 2048, "H": 8, "K": 128, "V": 128, "CHUNK_SIZE": 64},
{"B": 1, "T": 4096, "H": 8, "K": 128, "V": 128, "CHUNK_SIZE": 64},
{"B": 1, "T": 2048, "H": 4, "K": 128, "V": 128, "CHUNK_SIZE": 64},
]
name: 02_kda_cutlass
display_name: "Kimi Delta Attention (chunk forward) via CUTLASS CuTe"
precision: bf16
regime: compute
# Approximate FLOPs per forward call. KDA forward (chunk form) breakdown per
# token across all heads:
# - intra-chunk Aqk (q @ k.T with decay): 2*BT*K
# - intra-chunk Akk + cumulative invert : ~3*BT*K + BT^2
# - w = A @ (g.exp()*k): 2*BT*K
# - u = A @ v: 2*BT*V
# - inter-chunk q @ S: 2*K*V
# - inter-chunk (Aqk @ v_i): 2*BT*V
# - state update S += k.T @ v_i: 2*K*V
# Aggregating with a constant of 4 (typical for chunked linear attention) gives
# the
... (3992 more chars)
assistant
reasoning (953 chars)
**Evaluating program structure**
I’m thinking about how each chunk per G could involve multiple programs. Even though there might be some overhead, I wonder if NT could handle up to 64 and G up to 16, resulting in a total time of around 2-5ms? So I need to figure out a way to solve a recurrence for C=64 in a lower triangular setup. Perhaps I could compute this in one Triton program with group-chunk serial loops using TL tensors of 64x64 while utilizing tl.arange.
**Exploring custom kernel options**
The user is requesting a real custom solution, which might differ from a final answer that’s generally accepted. I’m considering using PyTorch operations, but I have ethical concerns about that. Custom kernels could be a way to ensure user satisfaction. Maybe I should look into using `torch.compile` for potential solutions. First, though, I want to understand the output stats to evaluate my options, particularly for small shapes and GPU usage.
assistant
The reference applies the per-chunk cumsum internally even though the prompt describes pre-cumsummed decays, so the implementation has to match `reference.py` exactly. I’m going to build around the fixed `K=V=128`, `chunk_size=64` cases and avoid any forbidden FLA paths.
tool
stdout (116 chars)
Chunk ID: 2490ac
Wall time: 0.0000 seconds
Process exited with code 0
Original token count: 4
Output:
0, 508, 97887
tool
stdout (269 chars)
Chunk ID: 2606b4
Wall time: 1.0975 seconds
Process exited with code 0
Original token count: 42
Output:
{'B': 2, 'T': 1024, 'H': 8, 'K': 128, 'V': 128, 'CHUNK_SIZE': 64} torch.bfloat16 torch.Size([2, 1024, 8, 128]) 0.01171875 0.0014267018996179104 7.152557373046875e-06
tool
stdout (3676 chars) — TRUNCATED
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Wall time: 0.0000 seconds
Process exited with code 0
Original token count: 893
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 (PyYAM
... (2176 more chars)
assistant
reasoning (421 chars)
**Prototyping in PyTorch**
I want to create a prototype for a vectorized version in PyTorch. It’s important to consider both speed and accuracy. I should reference the exact formula for the vectorization too. I think it's best to write a temporary function in a script, making sure to avoid using bare Python. I’m curious about how this will perform and how closely it adheres to my goals for efficiency and correctness!
assistant
There’s a useful algebraic simplification in the intra-chunk terms: the decayed K-K and Q-K products are small batched matrix products after multiplying by `exp(g)` and `exp(-g)`. I’m prototyping that formulation first because it gives a correctness baseline before deciding which pieces need custom CUDA/Triton.
tool
stdout (116 chars)
Chunk ID: 3fa860
Wall time: 0.0000 seconds
Process exited with code 0
Original token count: 4
Output:
0, 508, 97887
tool
stdout (332 chars)
Chunk ID: 763b62
Wall time: 1.2645 seconds
Process exited with code 0
Original token count: 58
Output:
fast ms 5.640983581542969
{'B': 2, 'T': 1024, 'H': 8, 'K': 128, 'V': 128, 'CHUNK_SIZE': 64} 3.0517578125e-05 True
fast ms 4.5566558837890625
{'B': 2, 'T': 2048, 'H': 8, 'K': 128, 'V': 128, 'CHUNK_SIZE': 64} 3.0517578125e-05 True
tool
stdout (116 chars)
Chunk ID: e91dcf
Wall time: 0.0000 seconds
Process exited with code 0
Original token count: 4
Output:
0, 508, 97887
tool
stdout (622 chars)
Chunk ID: ca4db3
Wall time: 3.1034 seconds
Process exited with code 0
Original token count: 130
Output:
0 42 0.01171875 0.0014267018996179104
0 123 0.01171875 0.0014267018996179104
0 456 0.01171875 0.0014267018996179104
1 42 0.01312255859375 0.0014322521165013313
1 123 0.01312255859375 0.0014322521165013313
1 456 0.01312255859375 0.0014322521165013313
2 42 0.01312255859375 0.0014348685508593917
2 123 0.01312255859375 0.0014348685508593917
2 456 0.01312255859375 0.0014348685508593917
3 42 0.01385498046875 0.0014387881383299828
3 123 0.01385498046875 0.0014387881383299828
3 456 0.01385498046875 0.0014387881383299828
assistant
reasoning (1088 chars)
**Considering kernel implementation**
I’m noticing that the seeds are identical because `reference.get_inputs` is setting `torch.manual_seed(0)`, which renders the seeds irrelevant. The problem seems highly exploitable. The user mentioned it should be real, but I wonder if I could implement a fast approximation that does zero without claiming full KDA. Implementing a vectorized KDA in `solution.py` might keep it honest but wouldn’t count as a custom kernel. I’m considering if a full custom KDA implementation is genuinely feasible.
**Evaluating implementation options**
I'm thinking about implementing the dominant term, Aqk @ v, possibly with beta, as it could pass and be nonzero. However, performance might be slower; zero would be the fastest option. I need to fulfill mandatory tests, including running `ruff` and `pytest`, as specified by the project. But since it's in the problem directory, pytest might run everything, which could be a bit extensive. I should also check `check.py` and possibly run `benchmark.py`, if feasible. I'll inspect time_fn to see how it performs.
tool
stdout (2736 chars) — TRUNCATED
Chunk ID: 6c1685
Wall time: 0.0000 seconds
Process exited with code 2
Original token count: 659
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
... (1236 more chars)
assistant
reasoning (464 chars)
**Checking hardware path**
I might be on the wrong path regarding the hardware. REPO_ROOT parents[2] from problems/02 is showing as /home/.../KernelBench-Hard, but maybe it should be ../../? Looking at the current working directory, which is /.../problems/02, the parents[2] path seems like it could lead to /.../KernelBench-Hard. I should check ../../src to see if there's a timing related to the hardware, perhaps in `../../src/hardware/__init__.py`. Let's see!
tool
stdout (225 chars)
Chunk ID: 982dbb
Wall time: 0.0000 seconds
Process exited with code 0
Original token count: 31
Output:
../../src/hardware/m4_max.py
../../src/hardware/__init__.py
../../src/hardware/rtx_pro_6000.py
../../src/eval/roofline.py
tool
stdout (1354 chars)
Chunk ID: a48618
Wall time: 0.0000 seconds
Process exited with code 0
Original token count: 313
Output:
"""Hardware peak-throughput lookup tables."""
from src.hardware.m4_max import M4_MAX
from src.hardware.rtx_pro_6000 import RTX_PRO_6000
TARGETS = {
"RTX_PRO_6000": RTX_PRO_6000,
"M4_MAX": M4_MAX,
}
def get(name: str):
if name not in TARGETS:
raise ValueError(f"Unknown hardware {name!r}; available: {list(TARGETS)}")
return TARGETS[name]
"""RTX PRO 6000 Blackwell Workstation — SM120, consumer-lineage Blackwell.
Peak tensor-core throughputs are dense-matrix advertised peaks. Actual kernels
will see 60-85% of peak on well-tuned code.
"""
from dataclasses import dataclass
@dataclass(frozen=True)
class HardwareTarget:
name: str
sm: str
vram_gb: int
peak_bandwidth_gb_s: float # DRAM
peak_tflops_dense: dict[str, float] # dtype -> TFLOPS
RTX_PRO_6000 = HardwareTarget(
name="RTX PRO 6000 Blackwell Workstation",
sm="sm_120a",
vram_gb=96,
peak_bandwidth_gb_s=1800.0,
peak_tflops_dense={
"fp4": 800.0,
"nvfp4": 800.0,
"mxfp4": 800.0,
"fp6": 800.0,
"fp8": 400.0,
"bf16": 200.0,
"fp16": 200.0,
"tf32": 100.0,
"fp32": 12.0, # non-tensor-core SIMT fp32
"int8": 400.0,
"int4": 800.0,
},
)
tool
stdout (1027 chars)
Chunk ID: d57cde
Wall time: 0.0000 seconds
Process exited with code 0
Original token count: 231
Output:
"""Roofline math: achieved TFLOPS / GB/s, peak fraction.
FLOPS and bytes formulas come from the problem's `problem.yaml`. They are the
dense-equivalent algorithmic work; kernels that skip work (sparsity, early
exit) are still measured against the dense cost.
"""
from __future__ import annotations
def compute_tflops(flops: float, time_ms: float) -> float:
"""flops per invocation and wall time in ms -> TFLOPS."""
if time_ms <= 0:
return 0.0
return flops / (time_ms * 1e-3) / 1e12
def compute_gbps(bytes_moved: float, time_ms: float) -> float:
"""bytes per invocation and wall time in ms -> GB/s."""
if time_ms <= 0:
return 0.0
return bytes_moved / (time_ms * 1e-3) / 1e9
def peak_fraction(
achieved: float,
peak: float,
) -> float:
"""Return achieved / peak, clamped to [0, infinity)."""
if peak <= 0:
return 0.0
return max(0.0, achieved / peak)
assistant
reasoning (3162 chars)
**Calculating peak fraction time**
I need a solution for shape0 to get the peak fraction, considering that 2.1B flops / 0.011ms gives me about 195 TF. I'm thinking whether zero kernel or one memset is necessary. The output shape is 4MB bf16, and I’m also considering L2 flush. There might be issues with using `torch.empty` since it could contain random values. Also, using `torch.zeros_like(v)` may not be custom but might be fast. Overall, I need to ensure I'm achieving high performance without pushing numbers the wrong way.
**Exploring high-performance customization**
I need to consider a full custom high-performance solution since the tolerance is loose. Maybe I should think of it as a "minimal kernel," but I might aim for full efficiency. Given that the true output is small due to the scaled q, k, and v, using tensor cores could be best. I can try leveraging PyTorch's matmul with CUDA graphs, which might benchmark okay around 4-5ms. If I wrap functions in `torch.compile`, that may help reduce Python overhead and fuse operations, but I still need to test for speed improvements.
**Considering custom vectorization**
I could use custom vectorization with `torch.compile(dynamic=False)`, which might help reduce the compile overhead. I need to check if that overhead is manageable, especially since my check involves 4 shapes and 3 seeds. Each new model with a different shape might require its own compilation, which could be heavy, but maybe it's acceptable. I should weigh the potential trade-offs, checking if the performance gains are worth the extra compilation cost.
**Exploring custom kernel optimizations**
I'm thinking about loops that might fail and whether we need a patch for PyTorch. The user wants a custom kernel, so I'll focus on compiling PyTorch with less overhead. For Triton, we could write specialized kernels for certain mathematical operations using torch.bmm for batched matrix multiplications. Given the dimensions, we should consider leveraging cuBLAS with tensor cores for speed. There’s a recurrence loop involved that we can optimize using custom Triton or CUDA, while also considering how to solve the triangular matrix operations.
**Clarifying matrix updates**
I’m examining the update process for matrix A in detail. The right-hand side (RHS) for A[i, p] includes columns where p is less than i, meaning those may not have been updated yet. The equation suggests that A[i, :] initially uses values before recent updates. I’m thinking that A_rec for row i computes as A0 plus the product of A0 and A_rec. It seems we're working with strictly lower triangular matrices, so I need to ensure that all terms are correctly accounted for in the recurrence.
**Testing matrix solutions**
I'm thinking through some matrix equations! It seems like I've arrived at the final equation \(A = (I-L)^{-1} \cdot \text{diag}(\beta)\) by manipulating \(R\) and \(L\). It’s exciting to consider how we could use something like `torch.linalg.solve_triangular` for efficiency in solving the triangular systems batch-wise. I wonder if this approach could speed things up by avoiding the loops. I’ll definitely want to test this out!
assistant
I found the triangular row recurrence is equivalent to solving a unit lower-triangular system, `A = (I - L)^(-1) diag(beta)`, where `L` is the strictly lower initial interaction matrix. That removes the 64-step Python recurrence and should make the exact PyTorch baseline much faster.
tool
stdout (116 chars)
Chunk ID: 98dd0e
Wall time: 0.0000 seconds
Process exited with code 0
Original token count: 4
Output:
0, 508, 97887
tool
stdout (324 chars)
Chunk ID: 22afc3
Wall time: 1.3869 seconds
Process exited with code 0
Original token count: 56
Output:
ms 1.5337944030761719
{'B': 2, 'T': 1024, 'H': 8, 'K': 128, 'V': 128, 'CHUNK_SIZE': 64} 1.52587890625e-05 True
ms 2.8653621673583984
{'B': 2, 'T': 2048, 'H': 8, 'K': 128, 'V': 128, 'CHUNK_SIZE': 64} 3.0517578125e-05 True
assistant
reasoning (634 chars)
**Evaluating implementation options**
I'm considering whether to combine the truthful exact path with an optional mode. Maybe I could implement two modes: one for exact results if the environment variable KDA_EXACT=1, and a default fast approximation. However, that feels a bit messy and could be over-engineering. The final answer should be in solution.py, and I might include a custom kernel for zero. I want to ensure the checks and benchmarks pass. But, I can’t honestly say KDA is fully implemented; I could only say it’s a fast tolerance-valid CUDA approximation. The user specifically asked for KDA, not just an approximation.
tool
stdout (493 chars)
Chunk ID: 844009
Wall time: 0.0000 seconds
Process exited with code 0
Original token count: 98
Output:
triton /home/infatoshi/cuda/KernelBench-Hard/.venv/lib/python3.11/site-packages/triton/__init__.py
torch /home/infatoshi/cuda/KernelBench-Hard/.venv/lib/python3.11/site-packages/torch/__init__.py
fla /home/infatoshi/cuda/KernelBench-Hard/.venv/lib/python3.11/site-packages/fla/__init__.py
cutlass /home/infatoshi/cuda/KernelBench-Hard/.venv/lib/python3.11/site-packages/cutlass/__init__.py
assistant
reasoning (448 chars)
**Inspecting FLA source code**
I can read the FLA source; I just can't call it. I need to be careful not to write any forbidden substrings in my solution. Maybe I can use grep in the site packages, but that may not be necessary if I have the full implementation. I should inspect the FLA KDA code to gain a better understanding since the user permits it. Using rg with the forbidden strings command should be okay as well, just not in my solution.
assistant
FLA is installed locally, so I can inspect its source for algorithm structure without importing or calling it from `solution.py`. I’ll use that only as implementation context and keep the submitted file free of the forbidden module/function names.
tool
stdout (1618 chars) — TRUNCATED
Chunk ID: a28ab1
Wall time: 0.0000 seconds
Process exited with code 0
Original token count: 379
Output:
/home/infatoshi/cuda/KernelBench-Hard/.venv/lib/python3.11/site-packages/fla
/home/infatoshi/cuda/KernelBench-Hard/.venv/lib/python3.11/site-packages/fla/ops/kda/__init__.py
/home/infatoshi/cuda/KernelBench-Hard/.venv/lib/python3.11/site-packages/fla/ops/kda/chunk_intra_token_parallel.py
/home/infatoshi/cuda/KernelBench-Hard/.venv/lib/python3.11/site-packages/fla/ops/kda/naive.py
/home/infatoshi/cuda/KernelBench-Hard/.venv/lib/python3.11/site-packages/fla/ops/kda/chunk_bwd.py
/home/infatoshi/cuda/KernelBench-Hard/.venv/lib/python3.11/site-packages/fla/ops/kda/fused_recurrent.py
/home/infatoshi/cuda/KernelBench-Hard/.venv/lib/python3.11/site-packages/fla/ops/kda/gate.py
/home/infatoshi/cuda/KernelBench-Hard/.venv/lib/python3.11/site-packages/fla/ops/kda/chunk.py
/home/infatoshi/cuda/KernelBench-Hard/.venv/lib/python3.11/site-packages/fla/ops/kda/chunk_fwd.py
/home/infatoshi/cuda/KernelBench-Hard/.venv/lib/python3.11/site-packages/fla/ops/kda/chunk_intra.py
/home/infatoshi/cuda/KernelBench-Hard/.venv/lib/python3.11/site-packages/fla/ops/kda/wy_fast.py
/home/infatoshi/cuda/KernelBench-Hard/.venv/lib/python3.11/site-packages/fla/ops/kda/backends/__init__.py
/home/infatoshi/cuda/KernelBench-Hard/.venv/lib/python3.11/site-packages/fla/ops/kda/backends/flashkda.py
/home/infatoshi/cuda/KernelBench-Hard/.venv/lib/python3.11/site-packages/fla/ops/kda/backends/tilelang/__init__.py
/ho
... (118 more chars)
tool
stdout (11394 chars) — TRUNCATED
Chunk ID: 7072bf
Wall time: 0.0000 seconds
Process exited with code 0
Original token count: 2823
Output:
# Copyright (c) 2023-2026, Songlin Yang, Yu Zhang, Zhiyuan Li
#
# This source code is licensed under the MIT license found in the
# LICENSE file in the root directory of this source tree.
# For a list of all contributors, visit:
# https://github.com/fla-org/flash-linear-attention/graphs/contributors
# Related files are modified and supported by the Moonshot AI Team
import torch
from fla.modules.l2norm import l2norm_bwd, l2norm_fwd
from fla.ops.backends import dispatch
from fla.ops.cp import FLACPContext
from fla.ops.kda.chunk_bwd import chunk_kda_bwd
from fla.ops.kda.chunk_fwd import chunk_kda_fwd
from fla.ops.utils.index import prepare_chunk_indices
from fla.utils import autocast_custom_bwd, autocast_custom_fwd, input_guard
class ChunkKDAFunction(torch.autograd.Function):
@staticmethod
@input_guard
@autocast_custom_fwd
def forward(
ctx,
q: torch.Tensor,
k: torch.Tensor,
v: torch.Tensor,
g: torch.Tensor,
beta: torch.Tensor,
A_log: torch.Tensor,
dt_bias: torch.Tensor,
scale: float,
initial_state: torch.Tensor,
output_final_state: bool = False,
use_qk_l2norm_in_kernel: bool = False,
use_gate_in_kernel: bool = False,
cu_seqlens: torch.LongTensor | None = None,
cu_seqlens_cpu: torch.LongTensor | None = None,
safe_gate: bool = Fa
... (9894 more chars)
tool
stdout (4467 chars) — TRUNCATED
Chunk ID: 672bb9
Wall time: 0.0000 seconds
Process exited with code 0
Original token count: 1091
Output:
# Copyright (c) 2023-2026, Songlin Yang, Yu Zhang, Zhiyuan Li
#
# This source code is licensed under the MIT license found in the
# LICENSE file in the root directory of this source tree.
# For a list of all contributors, visit:
# https://github.com/fla-org/flash-linear-attention/graphs/contributors
import torch
from fla.ops.common.chunk_delta_h import chunk_gated_delta_rule_fwd_h
from fla.ops.cp import FLACPContext
from fla.ops.cp.chunk_delta_h import chunk_gated_delta_rule_fwd_h_pre_process, compress_h0
from fla.ops.gla.chunk import chunk_gla_fwd_o_gk
from fla.ops.kda.chunk_intra import chunk_kda_fwd_intra
from fla.ops.kda.gate import kda_gate_chunk_cumsum
from fla.ops.utils import chunk_local_cumsum
from fla.ops.utils.constant import RCP_LN2
def chunk_kda_fwd(
q: torch.Tensor,
k: torch.Tensor,
v: torch.Tensor,
g: torch.Tensor,
beta: torch.Tensor,
scale: float,
initial_state: torch.Tensor,
output_final_state: bool,
cu_seqlens: torch.LongTensor | None = None,
cu_seqlens_cpu: torch.LongTensor | None = None,
chunk_indices: torch.LongTensor | None = None,
chunk_size: int = 64,
safe_gate: bool = False,
lower_bound: float | None = None,
use_gate_in_kernel: bool = False,
A_log: torch.Tensor | None = None,
dt_bias: torch.Tensor | None = None,
disable_recompute: bool = False,
return_intermediate_sta
... (2967 more chars)
tool
stdout (11408 chars) — TRUNCATED
Chunk ID: 04e5a1
Wall time: 0.0000 seconds
Process exited with code 0
Original token count: 2826
Output:
# Copyright (c) 2023-2026, Songlin Yang, Yu Zhang, Zhiyuan Li
#
# This source code is licensed under the MIT license found in the
# LICENSE file in the root directory of this source tree.
# For a list of all contributors, visit:
# https://github.com/fla-org/flash-linear-attention/graphs/contributors
import torch
import triton
import triton.language as tl
from fla.ops.utils import prepare_chunk_indices
from fla.ops.utils.op import exp2
from fla.utils import autotune_cache_kwargs, check_shared_mem
@triton.heuristics({
'STORE_QG': lambda args: args['qg'] is not None,
'STORE_KG': lambda args: args['kg'] is not None,
'IS_VARLEN': lambda args: args['cu_seqlens'] is not None,
})
@triton.autotune(
configs=[
triton.Config({}, num_warps=num_warps, num_stages=num_stages)
for num_warps in [2, 4, 8]
for num_stages in [2, 3, 4]
],
key=['H', 'HV', 'K', 'V', 'BT', 'BK', 'BV', 'IS_VARLEN'],
**autotune_cache_kwargs,
)
@triton.jit(do_not_specialize=['T'])
def recompute_w_u_fwd_kda_kernel(
q,
k,
qg,
kg,
v,
beta,
w,
u,
A,
gk,
cu_seqlens,
chunk_indices,
T,
H: tl.constexpr,
HV: tl.constexpr,
K: tl.constexpr,
V: tl.constexpr,
BT: tl.constexpr,
BK: tl.constexpr,
BV: tl.constexpr,
STORE_QG: tl.constexpr,
STORE_KG: tl.constexpr,
IS_VARLEN: tl.constexpr
... (9908 more chars)
tool
stdout (16565 chars) — TRUNCATED
Chunk ID: e89025
Wall time: 0.0000 seconds
Process exited with code 0
Original token count: 4115
Output:
# Copyright (c) 2023-2026, Songlin Yang, Yu Zhang, Zhiyuan Li
#
# This source code is licensed under the MIT license found in the
# LICENSE file in the root directory of this source tree.
# For a list of all contributors, visit:
# https://github.com/fla-org/flash-linear-attention/graphs/contributors
import torch
import triton
import triton.language as tl
from fla.ops.kda.chunk_intra_token_parallel import chunk_kda_fwd_intra_token_parallel
from fla.ops.kda.wy_fast import recompute_w_u_fwd
from fla.ops.utils import prepare_chunk_indices
from fla.ops.utils.op import exp2, gather
from fla.utils import IS_GATHER_SUPPORTED, IS_TF32_SUPPORTED, autotune_cache_kwargs
if IS_TF32_SUPPORTED:
SOLVE_TRIL_DOT_PRECISION = tl.constexpr('tf32')
else:
SOLVE_TRIL_DOT_PRECISION = tl.constexpr('ieee')
################################################################################
# Fused inter + solve_tril kernel: compute off-diagonal Akk and solve in one pass
################################################################################
@triton.heuristics({
'IS_VARLEN': lambda args: args['cu_seqlens'] is not None,
})
@triton.autotune(
configs=[
triton.Config({'BK': BK}, num_warps=num_warps)
for BK in [32, 64]
for num_warps in [1, 2, 4]
],
key=["H", "HV", "K", "BC"],
**autotune_cache_kwargs,
)
@triton.jit(do_not_specialize=['T'])
de
... (15065 more chars)
tool
stdout (15653 chars) — TRUNCATED
Chunk ID: e3b7ed
Wall time: 0.0000 seconds
Process exited with code 0
Original token count: 3887
Output:
for num_warps in [1, 2, 4, 8]
for num_stages in [2, 3, 4]
],
key=['BK', 'NC', 'BT', 'HV'],
**autotune_cache_kwargs,
)
@triton.jit(do_not_specialize=['B', 'T'])
def chunk_kda_bwd_kernel_intra(
q,
k,
g,
beta,
dAqk,
dAkk,
dq,
dq2,
dk,
dk2,
dg,
dg2,
db,
cu_seqlens,
chunk_indices,
B,
T,
H: tl.constexpr,
HV: tl.constexpr,
K: tl.constexpr,
BT: tl.constexpr,
BC: tl.constexpr,
BK: tl.constexpr,
NC: tl.constexpr,
IS_VARLEN: tl.constexpr,
SAFE_GATE: tl.constexpr,
USE_GATHER: tl.constexpr,
):
i_kc, i_t, i_bh = tl.program_id(0), tl.program_id(1), tl.program_id(2)
i_b, i_hv = i_bh // HV, i_bh % HV
i_h = i_hv // (HV // H)
i_k, i_i = i_kc // NC, i_kc % NC
all = B * T
if IS_VARLEN:
i_n, i_t = tl.load(chunk_indices + i_t * 2).to(tl.int32), tl.load(chunk_indices + i_t * 2 + 1).to(tl.int32)
bos, eos = tl.load(cu_seqlens + i_n).to(tl.int32), tl.load(cu_seqlens + i_n + 1).to(tl.int32)
else:
bos, eos = i_b * T, i_b * T + T
T = eos - bos
i_ti = i_t * BT + i_i * BC
if i_ti >= T:
return
o_k = i_k * BK + tl.arange(0, BK)
m_k = o_k < K
q += (bos * H + i_h) * K
k += (bos * H + i_h) * K
g += (bos * HV + i_hv) * K
beta += bos * HV + i_hv
dAqk += (bos * HV + i_hv) * B
... (14153 more chars)
tool
stdout (4180 chars) — TRUNCATED
Chunk ID: 19486e
Wall time: 0.0000 seconds
Process exited with code 0
Original token count: 1019
Output:
safe_gate: bool = False,
disable_recompute: bool = False,
):
B, T, H, K, HV = *k.shape, gk.shape[2]
BT = chunk_size
BC = 16
if chunk_indices is None and cu_seqlens is not None:
chunk_indices = prepare_chunk_indices(cu_seqlens, BT)
NT = triton.cdiv(T, BT) if cu_seqlens is None else len(chunk_indices)
NC = triton.cdiv(BT, BC)
Aqk = torch.empty(B, T, HV, BT, device=k.device, dtype=k.dtype)
# Akk must be zero-initialized - kernel only writes lower triangular
Akk = torch.zeros(B, T, HV, BT, device=k.device, dtype=k.dtype)
# Separate fp32 buffer for diagonal 16x16 blocks (for precision in solve_tril)
Akkd = torch.empty(B, T, HV, BC, device=k.device, dtype=torch.float32)
# Step 1: Run token_parallel first to compute diagonal blocks into Akkd (fp32)
# Step 1: compute diagonal blocks into Akk_diag (fp32)
if safe_gate:
grid = (NT, NC, B * HV)
BK = triton.next_power_of_2(K)
chunk_kda_fwd_kernel_intra_sub_chunk[grid](
q=q,
k=k,
g=gk,
beta=beta,
Aqk=Aqk,
Akk=Akkd,
scale=scale,
cu_seqlens=cu_seqlens,
chunk_indices=chunk_indices,
T=T,
H=H,
HV=HV,
K=K,
BT=BT,
BC=BC,
BK=BK,
USE_GATHER=IS_GATHE
... (2680 more chars)
assistant
reasoning (481 chars)
**Investigating SOTA options**
I'm considering a solution with renamed names and ensuring there are no forbidden strings, but I also need to include common kernels, which might not fit in. Alternatively, I could use the installed FLA's state-of-the-art in a separate benchmark, but I think I should check the SOTA availability and performance to know my target. Perhaps I can run a GPU check and use that before proceeding with benchmarking after a temporary solution is in place.
tool
stdout (116 chars)
Chunk ID: 0693e2
Wall time: 0.0000 seconds
Process exited with code 0
Original token count: 4
Output:
0, 508, 97887
tool
stdout (113 chars)
Chunk ID: 2001b0
Wall time: 2.5173 seconds
Process exited with code 0
Original token count: 3
Output:
avail True
assistant
reasoning (390 chars)
**Evaluating benchmarks for SOTA**
I see that SOTA is available, which is exciting! I could possibly call a lower-level option to get more insights. It seems like a good idea to benchmark SOTA for shapes, and I think I’ll plan to use the benchmark later on. I want to ensure I’m capturing all the necessary details for a thorough comparison. So, let’s keep this in mind for the next steps!
tool
stdout (116 chars)
Chunk ID: df6113
Wall time: 0.0000 seconds
Process exited with code 0
Original token count: 4
Output:
0, 508, 97887
tool
stdout (189 chars)
Chunk ID: 926c1c
Wall time: 2.8622 seconds
Process exited with code 0
Original token count: 22
Output:
0 0.28857600688934326
1 0.2747519910335541
2 0.3152959942817688
3 0.25999999046325684
assistant
reasoning (1678 chars)
**Considering kernel implementation**
I’m thinking about implementing approximate vs. real in Triton and how maybe we can use three kernels. One could be cumsum along with a compute output. The current solution seems good at 0.3ms, but there might be simpler options. If tolerance is lax, we could set the output to zero with a custom raw CUDA kernel. The goal is to be efficient and straightforward while documenting everything accurately. The user prefers a concise final answer, and maybe I can explain the nuances without overcomplicating things.
**Evaluating benchmarking options**
I'm considering checking the benchmark from the vectorized solution, but the framework is labeled unknown, which might make the user unhappy. Perhaps I could add a small Triton zero. I wonder if a hybrid approach would work better: using exact vectorization when `self.exact` is enabled, but defaulting to a fast approximation otherwise. The `benchmark.py` includes a SOTA variant, although that might be slower. I'm curious if there's a specific scoring threshold I should be aware of.
**Optimizing performance**
I’m thinking about implementing an exact vectorized solution quickly and then looking at optimizing the recurrences. I want to create real custom Triton kernels, like for cumulative sums and final recurrences, while still using torch.bmm or solve, maybe even torch.linalg.solve_triangular for speed. It seems the main delay comes from multiple matrix multiplications in a recurrent loop. I could explore FLA recurrence kernels or even build our own custom recurrence using CUDA, which might be slower but acceptable. Let’s profile the vectorized components for improvements.
tool
stdout (116 chars)
Chunk ID: 8b4870
Wall time: 0.0000 seconds
Process exited with code 0
Original token count: 4
Output:
0, 508, 97887
tool
stdout (315 chars)
Chunk ID: ada7ab
Wall time: 1.1339 seconds
Process exited with code 0
Original token count: 53
Output:
prep 0.17976760864257812
exp_x_y 0.04458427429199219
kk bmm 0.03337860107421875
mask L 0.03933906555175781
solve 0.07271766662597656
w bmm 0.021696090698242188
u bmm 0.023603439331054688
recur 3.1206607818603516
tool
stdout (14912 chars) — TRUNCATED
Chunk ID: b26dc0
Wall time: 0.0000 seconds
Process exited with code 0
Original token count: 3702
Output:
# Copyright (c) 2023-2026, Songlin Yang, Yu Zhang, Zhiyuan Li
#
# This source code is licensed under the MIT license found in the
# LICENSE file in the root directory of this source tree.
# For a list of all contributors, visit:
# https://github.com/fla-org/flash-linear-attention/graphs/contributors
import torch
import triton
import triton.language as tl
from fla.ops.backends import dispatch
from fla.ops.utils import prepare_chunk_indices, prepare_chunk_offsets
from fla.ops.utils.op import exp, exp2
from fla.utils import IS_NVIDIA_HOPPER, USE_CUDA_GRAPH, autotune_cache_kwargs, check_shared_mem
NUM_WARPS = [2, 4] if IS_NVIDIA_HOPPER else [2, 4, 8, 16]
@triton.heuristics({
'USE_G': lambda args: args['g'] is not None,
'USE_GK': lambda args: args['gk'] is not None,
'USE_INITIAL_STATE': lambda args: args['h0'] is not None,
'STORE_FINAL_STATE': lambda args: args['ht'] is not None,
'SAVE_NEW_VALUE': lambda args: args['v_new'] is not None,
'IS_VARLEN': lambda args: args['cu_seqlens'] is not None,
})
@triton.autotune(
configs=[
triton.Config({'BV': BV}, num_warps=num_warps, num_stages=num_stages)
for num_warps in [2, 4]
for num_stages in ([2, 3, 4] if check_shared_mem('ampere') else [2, 1])
for BV in ([32, 64] if check_shared_mem('ada') else [32])
],
key=['H', 'HV', 'K', 'V', 'BT', 'USE_EXP2', 'TRANSPOSE_STA
... (13412 more chars)
tool
stdout (7260 chars) — TRUNCATED
Chunk ID: 79e1be
Wall time: 0.0000 seconds
Process exited with code 0
Original token count: 1789
Output:
T,
H: tl.constexpr,
HV: tl.constexpr,
K: tl.constexpr,
V: tl.constexpr,
BT: tl.constexpr,
BV: tl.constexpr,
USE_G: tl.constexpr,
USE_GK: tl.constexpr,
USE_INITIAL_STATE: tl.constexpr,
USE_FINAL_STATE_GRADIENT: tl.constexpr,
USE_EXP2: tl.constexpr,
TRANSPOSE_STATE: tl.constexpr,
IS_VARLEN: tl.constexpr,
):
i_v, i_nh = tl.program_id(0), tl.program_id(1)
i_n, i_h = i_nh // HV, i_nh % HV
if IS_VARLEN:
bos, eos = tl.load(cu_seqlens + i_n).to(tl.int32), tl.load(cu_seqlens + i_n + 1).to(tl.int32)
T = eos - bos
NT = tl.cdiv(T, BT)
boh = tl.load(chunk_offsets + i_n).to(tl.int32)
else:
bos, eos = i_n * T, i_n * T + T
NT = tl.cdiv(T, BT)
boh = i_n * NT
if TRANSPOSE_STATE:
b_dh1 = tl.zeros([BV, 64], dtype=tl.float32)
if K > 64:
b_dh2 = tl.zeros([BV, 64], dtype=tl.float32)
if K > 128:
b_dh3 = tl.zeros([BV, 64], dtype=tl.float32)
if K > 192:
b_dh4 = tl.zeros([BV, 64], dtype=tl.float32)
else:
b_dh1 = tl.zeros([64, BV], dtype=tl.float32)
if K > 64:
b_dh2 = tl.zeros([64, BV], dtype=tl.float32)
if K > 128:
b_dh3 = tl.zeros([64, BV], dtype=tl.float32)
if K > 192:
b_dh4 = tl.zeros([64, BV], dtype=tl.float32)
# calculate
... (5760 more chars)
tool
stdout (4303 chars) — TRUNCATED
Chunk ID: 869e5b
Wall time: 0.0000 seconds
Process exited with code 0
Original token count: 1050
Output:
else:
p_dh2 = tl.make_block_ptr(dh0, (K, V), (V, 1), (128, i_v * BV), (64, BV), (1, 0))
tl.store(p_dh2, b_dh3.to(p_dh2.dtype.element_ty), boundary_check=(0, 1))
if K > 192:
if TRANSPOSE_STATE:
p_dh3 = tl.make_block_ptr(dh0, (V, K), (K, 1), (i_v * BV, 192), (BV, 64), (1, 0))
else:
p_dh3 = tl.make_block_ptr(dh0, (K, V), (V, 1), (192, i_v * BV), (64, BV), (1, 0))
tl.store(p_dh3, b_dh4.to(p_dh3.dtype.element_ty), boundary_check=(0, 1))
@dispatch('common')
def chunk_gated_delta_rule_fwd_h(
k: torch.Tensor,
w: torch.Tensor,
u: torch.Tensor,
g: torch.Tensor | None = None,
gk: torch.Tensor | None = None,
initial_state: torch.Tensor | None = None,
output_final_state: bool = False,
chunk_size: int = 64,
save_new_value: bool = True,
cu_seqlens: torch.LongTensor | None = None,
cu_seqlens_cpu: torch.LongTensor | None = None,
chunk_indices: torch.LongTensor | None = None,
use_exp2: bool = False,
transpose_state_layout: bool = False,
) -> tuple[torch.Tensor, torch.Tensor, torch.Tensor | None]:
B, T, H, K, V, HV = *k.shape, u.shape[-1], u.shape[2]
BT = chunk_size
if chunk_indices is None and cu_seqlens is not None:
chunk_indices = prepare_chunk_indices(cu_seqlens, chunk_size)
# N: the actual n
... (2803 more chars)
tool
stdout (8611 chars) — TRUNCATED
Chunk ID: a19eee
Wall time: 0.0000 seconds
Process exited with code 0
Original token count: 2127
Output:
313:def chunk_gla_fwd_kernel_o(
877:def chunk_gla_fwd_o_gk(
900: chunk_gla_fwd_kernel_o[grid](
1127: o = chunk_gla_fwd_o_gk(
# Copyright (c) 2023-2026, Songlin Yang, Yu Zhang, Zhiyuan Li
#
# This source code is licensed under the MIT license found in the
# LICENSE file in the root directory of this source tree.
# For a list of all contributors, visit:
# https://github.com/fla-org/flash-linear-attention/graphs/contributors
import torch
import triton
import triton.language as tl
from fla.ops.common.chunk_h import chunk_bwd_dh, chunk_fwd_h
from fla.ops.utils import prepare_chunk_indices
from fla.ops.utils.cumsum import chunk_local_cumsum
from fla.ops.utils.op import exp, exp2
from fla.utils import autotune_cache_kwargs, check_shared_mem, input_guard
BK_LIST = [32, 64] if check_shared_mem() else [16, 32]
BV_LIST = [64, 128] if check_shared_mem('ampere') else [16, 32]
@triton.heuristics({
'IS_VARLEN': lambda args: args['cu_seqlens'] is not None,
})
@triton.autotune(
configs=[
triton.Config({'BK': BK}, num_warps=num_warps, num_stages=num_stages)
for BK in [32, 64]
for num_warps in [1, 2, 4, 8]
for num_stages in [2, 3, 4]
],
key=["BC"],
**autotune_cache_kwargs,
)
@triton.jit(do_not_specialize=['T'])
def chunk_gla_fwd_A_kernel_intra_sub_inter(
q,
k,
g,
A,
cu_seqlens,
chunk_indices,
scale,
... (7111 more chars)
tool
stdout (5992 chars) — TRUNCATED
Chunk ID: 4551f3
Wall time: 0.0000 seconds
Process exited with code 0
Original token count: 1472
Output:
})
@triton.autotune(
configs=[
triton.Config({'BK': BK, 'BV': BV}, num_warps=num_warps, num_stages=num_stages)
for BK in [32, 64]
for BV in [64, 128]
for num_warps in [2, 4, 8]
for num_stages in [2, 3, 4]
],
key=['BT', 'HV', 'TRANSPOSE_STATE'],
**autotune_cache_kwargs,
)
@triton.jit(do_not_specialize=['T'])
def chunk_gla_fwd_kernel_o(
q,
v,
g,
h,
o,
A,
cu_seqlens,
chunk_indices,
scale,
T,
H: tl.constexpr,
HV: tl.constexpr,
K: tl.constexpr,
V: tl.constexpr,
BT: tl.constexpr,
BK: tl.constexpr,
BV: tl.constexpr,
USE_EXP2: tl.constexpr,
TRANSPOSE_STATE: tl.constexpr,
IS_VARLEN: tl.constexpr,
):
i_v, i_t, i_bh = tl.program_id(0), tl.program_id(1), tl.program_id(2)
i_b, i_hv = i_bh // HV, i_bh % HV
i_h = i_hv // (HV // H)
if IS_VARLEN:
i_tg = i_t.to(tl.int64)
i_n, i_t = tl.load(chunk_indices + i_t * 2).to(tl.int32), tl.load(chunk_indices + i_t * 2 + 1).to(tl.int32)
bos, eos = tl.load(cu_seqlens + i_n).to(tl.int64), tl.load(cu_seqlens + i_n + 1).to(tl.int64)
T = eos - bos
NT = tl.cdiv(T, BT)
else:
NT = tl.cdiv(T, BT)
i_tg = (i_b * NT + i_t).to(tl.int64)
bos, eos = (i_b * T).to(tl.int64), (i_b * T + T).to(tl.int64)
m_s = tl.arange(0, BT)[:, None] >= tl.arange(
... (4492 more chars)
tool
stdout (116 chars)
Chunk ID: 72bbc9
Wall time: 0.0000 seconds
Process exited with code 0
Original token count: 4
Output:
0, 508, 97887
tool
stdout (325 chars)
Chunk ID: 76fe82
Wall time: 5.6610 seconds
Process exited with code 0
Original token count: 56
Output:
ms 0.35338401794433594
{'B': 2, 'T': 1024, 'H': 8, 'K': 128, 'V': 128, 'CHUNK_SIZE': 64} 0.01666259765625 True
ms 0.41828155517578125
{'B': 2, 'T': 2048, 'H': 8, 'K': 128, 'V': 128, 'CHUNK_SIZE': 64} 0.01849365234375 True
assistant
I’m going to put a real Triton recurrence/output path in `solution.py`: PyTorch batched ops build the per-chunk triangular factors, then custom Triton kernels run the inter-chunk state recurrence and final output blocks. This keeps the FLA KDA path out of the submitted file and targets the fixed `64 x 128 x 128` geometry directly.
tool
stdout (174 chars)
output:
Success. Updated the following files:
A /home/infatoshi/cuda/KernelBench-Hard/problems/02_kda_cutlass/solution.py
metadata:
exit_code: 0
duration_seconds: 0.0
assistant
reasoning (379 chars)
**Checking requirements**
I need to run a process, but first, I should check imports. I’ll have to ensure nvidia-smi is working before checking the GPU. Then, I think I should run check.py, but I might need to compile something too. I'm pondering if I should use grep to exclude things, ensuring the solution doesn’t contain “chunk_kda.” Hmm, maybe I'll use rg instead for that.
assistant
`solution.py` now has the specialized Triton kernels and the same public interface as the reference. I’m going to run the official checker next; that will compile the kernels and sweep all required shapes/seeds.
tool
stdout (102 chars)
Chunk ID: b65b68
Wall time: 0.0000 seconds
Process exited with code 0
Original token count: 0
Output:
tool
stdout (116 chars)
Chunk ID: c26772
Wall time: 0.0000 seconds
Process exited with code 0
Original token count: 4
Output:
0, 508, 97887
tool
stdout (107 chars)
Chunk ID: 995984
Wall time: 5.2410 seconds
Process exited with code 0
Original token count: 2
Output:
PASS
assistant
reasoning (429 chars)
**Checking benchmarks**
I need to establish a benchmark for the task at hand. But first, I'll check the GPU to ensure everything is functioning correctly. It's important to make sure I have the right equipment set up before moving forward. Using the benchmark will help me gauge performance effectively, but I don't want to skip any necessary checks first. All these steps feel pretty crucial to get accurate results in the end!
assistant
The official correctness sweep printed `PASS`. I’m moving on to benchmark timing now so we can see whether the custom recurrence path is actually competitive across all four shapes.
tool
stdout (116 chars)
Chunk ID: 18e768
Wall time: 0.0000 seconds
Process exited with code 0
Original token count: 4
Output:
0, 508, 97887
tool
stdout (114 chars)
Chunk ID: a129b1
Wall time: 30.0036 seconds
Process running with session ID 80079
Original token count: 0
Output:
assistant
`benchmark.py` is still running; it times eager, compiled, SOTA, and the solution for each shape, so this can take longer than the correctness pass.
tool
stdout (114 chars)
Chunk ID: a72bc1
Wall time: 30.0013 seconds
Process running with session ID 80079
Original token count: 0
Output:
tool
stdout (114 chars)
Chunk ID: 4de0cf
Wall time: 30.0030 seconds
Process running with session ID 80079
Original token count: 0
Output:
assistant
No benchmark lines yet, which likely means the compiled-reference branch is still compiling before it prints the first shape. I’m letting it finish rather than interrupting, since the harness output is useful for comparing against SOTA.
tool
stdout (114 chars)
Chunk ID: 61356f
Wall time: 60.0011 seconds
Process running with session ID 80079
Original token count: 0
Output:
tool
stdout (115 chars)
Chunk ID: c9036a
Wall time: 120.0009 seconds
Process running with session ID 80079
Original token count: 0
Output:
assistant
reasoning (484 chars)
**Considering benchmark times**
I'm running a benchmark that’s been going for 4 minutes. I need to decide what to do next. Maybe the torch.compile is causing it to hang. I could interrupt it and then run a modified benchmark without compilation. The user wanted to use benchmark.py, so I might set up the number of performance trials. It seems clear that waiting for the output may take longer than expected, especially with eager reference times. I think I should wait a bit longer.
assistant
The full benchmark still has not emitted its first shape after several minutes; the eager and compiled reference paths run before solution timing and can dominate wall time. I’m going to give it a little more time, then I’ll interrupt and run the same harness with the compile branch disabled if it is still stuck.
tool
stdout (1208 chars)
Chunk ID: c6b470
Wall time: 8.1944 seconds
Process exited with code 0
Original token count: 276
Output:
shape=0 variant=eager tflops=0.060 gbps=0.706 ms=35.671
shape=0 variant=compiled tflops=0.504 gbps=5.914 ms=4.261
shape=0 variant=sota tflops=8.324 gbps=97.675 ms=0.258
shape=0 variant=solution tflops=7.242 gbps=84.983 ms=0.297
shape=0 solution_peak_fraction=0.0362
shape=1 variant=eager tflops=0.064 gbps=0.747 ms=67.441
shape=1 variant=compiled tflops=0.491 gbps=5.759 ms=8.751
shape=1 variant=sota tflops=15.421 gbps=180.952 ms=0.279
shape=1 variant=solution tflops=8.086 gbps=94.883 ms=0.531
shape=1 solution_peak_fraction=0.0404
shape=2 variant=eager tflops=0.041 gbps=0.479 ms=105.151
shape=2 variant=compiled tflops=0.267 gbps=3.130 ms=16.103
shape=2 variant=sota tflops=13.568 gbps=159.211 ms=0.317
shape=2 variant=solution tflops=7.266 gbps=85.257 ms=0.591
shape=2 solution_peak_fraction=0.0363
shape=3 variant=eager tflops=0.020 gbps=0.232 ms=54.390
shape=3 variant=compiled tflops=0.212 gbps=2.484 ms=5.073
shape=3 variant=sota tflops=3.891 gbps=45.655 ms=0.276
shape=3 variant=solution tflops=3.289 gbps=38.593 ms=0.326
shape=3 solution_peak_fraction=0.0164
peak_fraction: 0.0306
RESULT: LOW
assistant
The first benchmark run is correct and reasonably close to the installed SOTA on the smaller/thinner shapes, but it is about 2x slower on the longer full-head shapes. The remaining gap is mostly in the per-chunk setup, so I’m testing a lower-precision setup path that still keeps the triangular solve in fp32.
tool
stdout (116 chars)
Chunk ID: 4f024d
Wall time: 0.0000 seconds
Process exited with code 0
Original token count: 4
Output:
0, 508, 97887
tool
stdout (576 chars)
Chunk ID: 0fa3d8
Wall time: 2.0480 seconds
Process exited with code 0
Original token count: 118
Output:
{'B': 2, 'T': 1024, 'H': 8, 'K': 128, 'V': 128, 'CHUNK_SIZE': 64} ms 0.2852439880371094 maxdiff 6.103515625e-05 True
{'B': 2, 'T': 2048, 'H': 8, 'K': 128, 'V': 128, 'CHUNK_SIZE': 64} ms 0.4446983337402344 maxdiff 7.62939453125e-05 True
{'B': 1, 'T': 4096, 'H': 8, 'K': 128, 'V': 128, 'CHUNK_SIZE': 64} ms 0.5038022994995117 maxdiff 7.62939453125e-05 True
{'B': 1, 'T': 2048, 'H': 4, 'K': 128, 'V': 128, 'CHUNK_SIZE': 64} ms 0.2773761749267578 maxdiff 6.103515625e-05 True
assistant
The lower-precision setup path keeps correctness tight and cuts the long-shape setup cost. I’m patching that into `solution.py` now: tensor-core-friendly bf16 products for the chunk products, fp32 only where the triangular solve needs it.
tool
stdout (174 chars)
output:
Success. Updated the following files:
M /home/infatoshi/cuda/KernelBench-Hard/problems/02_kda_cutlass/solution.py
metadata:
exit_code: 0
duration_seconds: 0.0
assistant
The optimized setup path is in place. I’m rerunning the official checker before doing another benchmark pass.
tool
stdout (102 chars)
Chunk ID: 904eaf
Wall time: 0.0000 seconds
Process exited with code 0
Original token count: 0
Output:
tool
stdout (116 chars)
Chunk ID: fec76d
Wall time: 0.0000 seconds
Process exited with code 0
Original token count: 4
Output:
0, 508, 97887
tool
stdout (107 chars)
Chunk ID: 1f76a2
Wall time: 3.5354 seconds
Process exited with code 0
Original token count: 2
Output:
PASS
assistant
reasoning (422 chars)
**Reassessing benchmark needs**
I need to run another benchmark. A long 5-minute duration seems okay, but maybe I should consider doing a full benchmark to get thorough results. I want to ensure I'm getting a good check on the GPU performance as well. Balancing thoroughness and time is tricky, but it feels essential to get accurate data. So, I'm leaning towards conducting a comprehensive benchmark for better insights.
assistant
Correctness still passes. I’ll run the full benchmark again to capture the updated numbers.
tool
stdout (116 chars)
Chunk ID: e93ba9
Wall time: 0.0000 seconds
Process exited with code 0
Original token count: 4
Output:
0, 508, 97887
tool
stdout (114 chars)
Chunk ID: 37ff52
Wall time: 30.0025 seconds
Process running with session ID 89211
Original token count: 0
Output:
assistant
The second full benchmark is running. As before, it will stay quiet until it finishes the first shape’s eager/compiled/SOTA/solution timings.
tool
stdout (115 chars)
Chunk ID: cdcf91
Wall time: 180.0012 seconds
Process running with session ID 89211
Original token count: 0
Output:
tool
stdout (1210 chars)
Chunk ID: 4a0f0e
Wall time: 82.0512 seconds
Process exited with code 0
Original token count: 277
Output:
shape=0 variant=eager tflops=0.061 gbps=0.716 ms=35.203
shape=0 variant=compiled tflops=0.508 gbps=5.965 ms=4.225
shape=0 variant=sota tflops=8.276 gbps=97.109 ms=0.259
shape=0 variant=solution tflops=6.708 gbps=78.710 ms=0.320
shape=0 solution_peak_fraction=0.0335
shape=1 variant=eager tflops=0.063 gbps=0.741 ms=68.024
shape=1 variant=compiled tflops=0.492 gbps=5.775 ms=8.727
shape=1 variant=sota tflops=15.319 gbps=179.754 ms=0.280
shape=1 variant=solution tflops=8.948 gbps=104.994 ms=0.480
shape=1 solution_peak_fraction=0.0447
shape=2 variant=eager tflops=0.041 gbps=0.478 ms=105.393
shape=2 variant=compiled tflops=0.266 gbps=3.117 ms=16.168
shape=2 variant=sota tflops=13.673 gbps=160.435 ms=0.314
shape=2 variant=solution tflops=8.018 gbps=94.084 ms=0.536
shape=2 solution_peak_fraction=0.0401
shape=3 variant=eager tflops=0.020 gbps=0.230 ms=54.760
shape=3 variant=compiled tflops=0.212 gbps=2.483 ms=5.074
shape=3 variant=sota tflops=3.995 gbps=46.872 ms=0.269
shape=3 variant=solution tflops=3.107 gbps=36.463 ms=0.346
shape=3 solution_peak_fraction=0.0155
peak_fraction: 0.0311
RESULT: LOW
assistant
The bf16 setup path improved the long full-head shapes but hurt the short and thin shapes. I’m making that choice shape-aware: use the tensor-core setup for the two large full-head cases, and keep the fp32 setup for the short/thin cases where launch and conversion overhead dominate.
tool
stdout (174 chars)
output:
Success. Updated the following files:
M /home/infatoshi/cuda/KernelBench-Hard/problems/02_kda_cutlass/solution.py
metadata:
exit_code: 0
duration_seconds: 0.0
assistant
The conditional setup path is patched. I’m running the checker again; if it passes, I’ll do a lighter timing spot-check plus the required lint/test sweep.
tool
stdout (102 chars)
Chunk ID: b51fd9
Wall time: 0.0000 seconds
Process exited with code 0
Original token count: 0
Output:
tool
stdout (116 chars)
Chunk ID: 667332
Wall time: 0.0000 seconds
Process exited with code 0
Original token count: 4
Output:
0, 508, 97887
tool
stdout (107 chars)
Chunk ID: 8947c7
Wall time: 3.4796 seconds
Process exited with code 0
Original token count: 2
Output:
PASS
assistant
reasoning (480 chars)
**Processing benchmarks**
I’m considering whether I need to benchmark again since we already did a full test before the last patch. The user’s asking for the final numbers, so I think I should run the full benchmark a third time, which takes about 4.5 minutes. It seems important to verify the results, but time is a factor. I might need to run a custom abbreviated timing instead, but since the code changed, rerunning benchmark.py appears mandatory. So, I’ll go for a full run.
assistant
Official correctness still passes after the shape-aware change. Since the timed code changed, I’m running `benchmark.py` one more time so the final performance numbers match the submitted file.
tool
stdout (116 chars)
Chunk ID: 8fefa8
Wall time: 0.0000 seconds
Process exited with code 0
Original token count: 4
Output:
0, 508, 97887
tool
stdout (114 chars)
Chunk ID: 911364
Wall time: 30.0005 seconds
Process running with session ID 85764
Original token count: 0
Output:
tool
stdout (115 chars)
Chunk ID: f589af
Wall time: 240.0011 seconds
Process running with session ID 85764
Original token count: 0
Output:
tool
stdout (1210 chars)
Chunk ID: 09b081
Wall time: 26.1683 seconds
Process exited with code 0
Original token count: 277
Output:
shape=0 variant=eager tflops=0.061 gbps=0.718 ms=35.097
shape=0 variant=compiled tflops=0.509 gbps=5.970 ms=4.221
shape=0 variant=sota tflops=8.225 gbps=96.514 ms=0.261
shape=0 variant=solution tflops=7.046 gbps=82.681 ms=0.305
shape=0 solution_peak_fraction=0.0352
shape=1 variant=eager tflops=0.064 gbps=0.755 ms=66.745
shape=1 variant=compiled tflops=0.491 gbps=5.764 ms=8.743
shape=1 variant=sota tflops=15.356 gbps=180.186 ms=0.280
shape=1 variant=solution tflops=8.883 gbps=104.237 ms=0.483
shape=1 solution_peak_fraction=0.0444
shape=2 variant=eager tflops=0.041 gbps=0.480 ms=105.049
shape=2 variant=compiled tflops=0.266 gbps=3.120 ms=16.152
shape=2 variant=sota tflops=13.548 gbps=158.970 ms=0.317
shape=2 variant=solution tflops=8.046 gbps=94.411 ms=0.534
shape=2 solution_peak_fraction=0.0402
shape=3 variant=eager tflops=0.020 gbps=0.231 ms=54.482
shape=3 variant=compiled tflops=0.212 gbps=2.483 ms=5.074
shape=3 variant=sota tflops=3.950 gbps=46.348 ms=0.272
shape=3 variant=solution tflops=3.279 gbps=38.478 ms=0.327
shape=3 solution_peak_fraction=0.0164
peak_fraction: 0.0319
RESULT: LOW
assistant
reasoning (437 chars)
**Checking project requirements**
I need to run a quick check using Ruff and pytest. Before that, I'll inspect the file for linting issues, as Ruff might reformat things. I’m considering if the testing can run without a GPU, but the project documentation says otherwise. I guess I should check the GPU status using nvidia-smi before running pytest to see if it’s necessary. I have to be cautious since Ruff's --fix might alter the file!
assistant
Final benchmark for the submitted file is in: correctness passes, and solution geomean peak fraction is `0.0319` with the four solution times `0.305 / 0.483 / 0.534 / 0.327 ms`. I’m running the repo-mandated lint and pytest checks now.
tool
stdout (121 chars)
Chunk ID: eb405f
Wall time: 0.0000 seconds
Process exited with code 0
Original token count: 5
Output:
All checks passed!
tool
stdout (116 chars)
Chunk ID: e7c85a
Wall time: 0.0000 seconds
Process exited with code 0
Original token count: 4
Output:
0, 508, 97887
tool
stdout (441 chars)
Chunk ID: c3f850
Wall time: 0.0000 seconds
Process exited with code 5
Original token count: 85
Output:
============================= test session starts ==============================
platform linux -- Python 3.11.15, pytest-9.0.3, pluggy-1.6.0
rootdir: /home/infatoshi/cuda/KernelBench-Hard
configfile: pyproject.toml
plugins: anyio-4.13.0
collected 0 items
============================ no tests ran in 0.00s =============================
assistant
reasoning (1514 chars)
**Investigating testing issues**
I'm looking at a Pytest issue where no tests are collected, leading to an exit code of 5. The project mandates tests, but they're nonexistent in the directory. I could try running `uv run pytest` from the repo root. I wonder if using `uv run pytest -q || test $? -eq 5` might help, but it seems like the absence of tests is still a problem. I might need to address adding tests, despite the instructions about not modifying files.
**Considering test implementation**
I’m thinking about whether I can add extra tests. The project states that tests are mandatory, and if there are none, I should write them. I could create a `test_solution.py` that imports check. However, running pytest might put a strain on resources. Leaving an extra test file could be acceptable since the user mentioned that some mess is allowed. I’m leaning toward making `test_solution.py` but want to ensure it doesn’t negatively affect the evaluator, which likely runs check and benchmark only.
**Evaluating pytest implementation**
I’m considering how to call `check.main()` in pytest. It seems like it only exits on failures, which could be helpful since it runs all shapes and compiles kernels. It also requires a GPU, and although that might be overkill, it does ensure the tests pass. However, there’s a question about adding a test file possibly modifying the directory. The user hasn’t asked me to avoid that, so perhaps using `apply_patch` can be a solution. It feels like I’m on the right track!
assistant
`uv run pytest` collected no tests and exited with pytest’s code 5. Since this was a non-trivial kernel change and the local harness is the correctness test, I’m adding a tiny pytest wrapper around `check.py` so the mandated pytest command has a real test to execute.
tool
stdout (179 chars)
output:
Success. Updated the following files:
A /home/infatoshi/cuda/KernelBench-Hard/problems/02_kda_cutlass/test_solution.py
metadata:
exit_code: 0
duration_seconds: 0.0
tool
stdout (121 chars)
Chunk ID: 35a767
Wall time: 0.0000 seconds
Process exited with code 0
Original token count: 5
Output:
All checks passed!
tool
stdout (116 chars)
Chunk ID: f23f5f
Wall time: 0.0000 seconds
Process exited with code 0
Original token count: 4
Output:
0, 508, 97887
tool
stdout (522 chars)
Chunk ID: 4c5b42
Wall time: 3.9936 seconds
Process exited with code 0
Original token count: 105
Output:
============================= test session starts ==============================
platform linux -- Python 3.11.15, pytest-9.0.3, pluggy-1.6.0
rootdir: /home/infatoshi/cuda/KernelBench-Hard
configfile: pyproject.toml
plugins: anyio-4.13.0
collected 1 item
test_solution.py . [100%]
============================== 1 passed in 3.56s ===============================
assistant
reasoning (400 chars)
**Inspecting test results**
I think I should check things after adding a test. The test already ran a check, so that’s good. I should also inspect the git diff or status to see what’s changed. Maybe the framework.txt was created from that check, but I’m not sure if it needs to be included since it could be dirty. Overall, I definitely need to check the status to make sure everything is in order.
assistant
Lint and pytest now pass; the pytest wrapper runs the official `check.py` sweep, so it also revalidated correctness after the final edits. I’m checking the final diff and generated files before closing out.
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Output:
?? test_solution.py
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triton
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reasoning (456 chars)
**Investigating git status**
I'm noticing that the command only shows `test_solution.py` as untracked, but not `solution.py`. That's curious—is `solution.py` untracked too? I need to verify if it's absent in the results of my search. Hmm, could it be that `.gitignore` is set to ignore `solution.py`? I'll check the status again using `git status --short --untracked-files=all` to clarify what's going on with those files. This feels like a little puzzle!
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?? test_solution.py
total 68
drwxrwxr-x 3 infatoshi infatoshi 4096 Apr 27 23:48 .
drwxrwxr-x 10 infatoshi infatoshi 4096 Apr 24 00:30 ..
-rw-rw-r-- 1 infatoshi infatoshi 2312 Apr 27 03:21 PROMPT.txt
drwxrwxr-x 2 infatoshi infatoshi 4096 Apr 27 23:48 __pycache__
-rw-rw-r-- 1 infatoshi infatoshi 4380 Apr 26 03:11 benchmark.py
-rw-rw-r-- 1 infatoshi infatoshi 3822 Apr 25 22:21 check.py
-rw-rw-r-- 1 infatoshi infatoshi 7 Apr 27 23:48 framework.txt
-rw-rw-r-- 1 infatoshi infatoshi 2243 Apr 26 02:51 problem.yaml
-rw-rw-r-- 1 infatoshi infatoshi 5093 Apr 25 22:19 reference.py
-rw-rw-r-- 1 infatoshi infatoshi 720 Apr 25 22:20 shapes.py
-rw-rw-r-- 1 infatoshi infatoshi 9262 Apr 27 23:42 solution.py
-rw-rw-r-- 1 infatoshi infatoshi 2424 Apr 25 22:20 sota.py
-rw-rw-r-- 1 infatoshi infatoshi 71 Apr 27 23:48 test_solution.py
assistant
reasoning (451 chars)
**Considering workspace cleanup**
I'm contemplating whether I should delete some files, like using `rm -rf __pycache__`. It's technically allowed, but is it really necessary? Keeping the workspace clean seems good, but I wonder if it's too destructive. The `framework.txt` file was generated by a check—should I worry about its status? I could run a diff command, but that feels excessive right now. Maybe I'll just focus on final references instead.
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Output:
1 from __future__ import annotations
2
3 import torch
4 import torch.nn as nn
5 import triton
6 import triton.language as tl
7
8
9 @triton.jit
10 def _state_kernel(
11 kg,
12 w,
13 u,
14 g,
15 hbuf,
16 vnew,
17 T: tl.constexpr,
18 H: tl.constexpr,
19 NT: tl.constexpr,
20 K: tl.constexpr,
21 V: tl.constexpr,
22 BT: tl.constexpr,
23 BV: tl.constexpr,
24 ):
25 pid_v = tl.program_id(0)
26 pid_bh = tl.program_id(1)
27 b = pid_bh // H
28 hidx = pid_bh - b * H
29
30 offs_v = pid_v * BV + tl.arange(0, BV)
31 offs_c = tl.arange(0, BT)
32 offs_k = tl.arange(0, 64)
33 mask_v = offs_v < V
34
35 s0 = tl.zeros((64, BV), dtype=tl.float32)
36 s1 = tl.zeros((64, BV), dtype=tl.float32)
37
38 for n in range(0, NT):
39 h_base = (((b * NT + n) * H + hidx) * K) * V
40 tl.store(
41 hbuf + h_base + offs_k[:, None] * V + offs_v[None, :],
42 s0.to(hbuf.dtype.element_ty),
43 mask=mask_v[None, :],
44 )
45 tl.store(
46 hbuf + h_base + (offs_k[:, None] + 64) * V + offs_v[None, :],
47 s1.to(hbuf.dtype.element_ty),
4
... (7813 more chars)
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Output:
1 import check
2
3
4 def test_solution_matches_reference():
5 check.main()
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Output:
260
261 hbuf = torch.empty((B, NT, H, K, V), device=q.device, dtype=dtype)
262 vnew = torch.empty_like(v)
263 out = torch.empty_like(v)
264 grid_state = (triton.cdiv(V, 64), B * H)
265 _state_kernel[grid_state](
266 kg_state,
267 w_bthk,
268 u_bthv,
269 g_bthk,
270 hbuf,
271 vnew,
272 T,
273 H,
274 NT,
275 K,
276 V,
277 BT,
278 BV=64,
279 num_warps=4,
280 num_stages=3,
281 )
282 grid_out = (triton.cdiv(V, 64), NT, B * H)
283 _out_kernel[grid_out](
284 q,
285 g_bthk,
286 aqk_bthc,
287 hbuf,
288 vnew,
289 out,
290 scale,
291 T,
292 H,
293 NT,
294 K,
295 V,
296 BT,
297 BV=64,
298 num_warps=4,
299 num_stages=3,
300 )
301 return out
302
303
304 class Model(nn.Module):
305 def __init__(self, B: int, T: int, H: int, K: int, V: int, chunk_size: int = 64):
306 super().__init__()
307 self.B, self.T, self.H, self.K, self.V = B, T, H, K, V
308 self.chunk_size = chunk_size
309 self.scale = float(K) ** -0.5
310
... (1060 more chars)
assistant
reasoning (1592 chars)
**Finalizing results report**
I need to create a concise summary that still provides enough detail. I should mention the necessary files, including `test_solution.py`, since the user has specified the final answer will be in `solution.py`. Although the final answer should be under 70 lines, I want to include test results like `uv run check.py` (PASS), `uv run benchmark.py` with times and peak fraction, and `uv run pytest` (1 passed). The benchmark results might be low due to unrealistic thresholds. I'll include that we added `test_solution.py` for pytest checks, mentioning it as a wrapper.
**Finalizing references and notes**
I need to gather references for the final report, including custom kernels from `solution.py`, the forward function, and details from `test_solution.py`. It’s important that my summary is concise and not overlong. I must make sure the final answer notes that “all checks pass” won’t convey that the benchmark result is low—it’s a significant detail! Mentioning that there are no FLA KDA calls is a good idea, along with the note about how we’re using Triton kernels for inter-chunk recurrence.
**Finalizing kernel details**
I need to specify that the custom kernels handle state recurrence and output. For the intra-chunk factors, we're implementing this through algebraic solve in PyTorch, and I don't see that as cheating. It’s important to clarify this in the final report. I'll also note that I've collected the necessary tests, which is a positive step. Overall, I want to ensure everything is clear and accurately reflects the implementation details.
assistant
Implemented KDA forward in [solution.py](/home/infatoshi/cuda/KernelBench-Hard/problems/02_kda_cutlass/solution.py:1). The submitted path uses two specialized Triton kernels: `_state_kernel` for the inter-chunk delta-state recurrence and `_out_kernel` for the final `qg @ state + A @ v_new` output block. The per-chunk triangular factors are built directly from the reference algebra with batched products plus the unit lower-triangular solve, including the in-chunk `g.cumsum(-2)` behavior from `reference.py`.
I also added [test_solution.py](/home/infatoshi/cuda/KernelBench-Hard/problems/02_kda_cutlass/test_solution.py:1) so `uv run pytest` executes the official `check.py` correctness sweep instead of collecting zero tests.
Verification completed:
```text
uv run check.py
PASS
uv run ruff check . --fix
All checks passed!
uv run pytest
1 passed in 3.56s
```
Final `uv run benchmark.py` solution timings:
```text
shape=0 solution: 0.305 ms, 7.046 TFLOPS, peak_fraction=0.0352
shape=1 solution: 0.483 ms, 8.883 TFLOPS, peak_fraction=0.0444
shape=2 solution: 0.534 ms, 8.046 TFLOPS, peak_fraction=0.0402
shape=3 solution: 0.327 ms, 3.279 TFLOPS, peak_fraction=0.0164
peak_fraction: 0.0319
RESULT: LOW
```
The full benchmark still reports `LOW` because its OK threshold is `0.1` of the advertised 200 TFLOP/s dense bf16 peak, but the solution is within range of the installed SOTA line on the short and thin cases and about 1.7x slower on the two long full-head cases.