---
id: pr-flash-attention-2510
repo: Dao-AILab/flash-attention
pr: 2510
title: '[Cute,Bwd,Sm90] Fix determinism for GQA, port Sm100 approach in'
author: v0i0
date: '2026-04-30'
url: https://github.com/Dao-AILab/flash-attention/pull/2510
source_category: upstream-code
architectures:
- sm100
- sm90
tags:
- cute
- sm100
- sm90
techniques: []
hardware_features:
- blackwell
- hopper
kernel_types:
- attention
languages:
- cute-dsl
captured_at: '2026-05-16'
status: merged
merge_sha: c5f6ff4905b924d20b5fc2fe74551638cd1421f4
inclusion_reason: Search-matched CUDA kernel optimization PR; materialize diff/source before synthesis.
changed_paths:
- flash_attn/cute/flash_bwd_sm90.py
- tests/cute/test_flash_attn_race_condition.py
artifact_dir: evidence/pull-bundles/flash-attention/gh-2510
head_ref_oid: 8bc74c445e861ba92d22d04e2f06771136a4fbed
---
# [Cute,Bwd,Sm90] Fix determinism for GQA, port Sm100 approach in

- Repository: `Dao-AILab/flash-attention`
- PR: [2510](https://github.com/Dao-AILab/flash-attention/pull/2510)
- Decision: `Search-matched CUDA kernel optimization PR; materialize diff/source before synthesis.`
- Reason: Search-matched CUDA kernel optimization PR; materialize diff/source before synthesis.

## Changed Paths

- `flash_attn/cute/flash_bwd_sm90.py`
- `tests/cute/test_flash_attn_race_condition.py`

## Evidence Bundle

`evidence/pull-bundles/flash-attention/gh-2510`
