---
id: pr-flash-attention-1940
repo: Dao-AILab/flash-attention
pr: 1940
title: '[Cute,Fwd,Sm100] Implement SplitKV'
author: timmy-feng
date: '2025-11-05'
url: https://github.com/Dao-AILab/flash-attention/pull/1940
source_category: upstream-code
architectures:
- sm100
- sm90
tags:
- FA4
- arch_pipeline
- attention_kv
- benchmark_test
- compiler_runtime
- cute dsl
- head_dim
- scheduler_autotune
- sm90
- tma
techniques:
- async-copy
- autotuning
- pipeline-stages
- tile-scheduling
hardware_features:
- blackwell
- hopper
- tma
kernel_types:
- attention
- compiler
- runtime
- scheduler
languages:
- cuda-cpp
- cute-dsl
captured_at: '2026-05-16'
status: merged
merge_sha: e724e2588cbe754beb97cf7c011b5e7e34119e62
inclusion_reason: 'Extract the architecture assumption first: SM target, TMA/WGMMA/tcgen path, cluster use, and pipeline stages.'
changed_paths:
- flash_attn/cute/block_info.py
- flash_attn/cute/flash_bwd.py
- flash_attn/cute/flash_bwd_postprocess.py
- flash_attn/cute/flash_bwd_preprocess.py
- flash_attn/cute/flash_bwd_sm100.py
- flash_attn/cute/flash_bwd_sm90.py
- flash_attn/cute/flash_fwd.py
- flash_attn/cute/flash_fwd_combine.py
- flash_attn/cute/flash_fwd_sm100.py
- flash_attn/cute/interface.py
- flash_attn/cute/seqlen_info.py
- flash_attn/cute/tile_scheduler.py
- tests/cute/test_flash_attn.py
artifact_dir: evidence/pull-bundles/flash-attention/gh-1940
head_ref_oid: 1f6ab9cea642dd92748284bb38c95dc775aa5cd1
---
# [Cute,Fwd,Sm100] Implement SplitKV

- Repository: `Dao-AILab/flash-attention`
- PR: [1940](https://github.com/Dao-AILab/flash-attention/pull/1940)
- Decision: `Extract the architecture assumption first: SM target, TMA/WGMMA/tcgen path, cluster use, and pipeline stages.`
- Reason: Extract the architecture assumption first: SM target, TMA/WGMMA/tcgen path, cluster use, and pipeline stages.

## Changed Paths

- `flash_attn/cute/block_info.py`
- `flash_attn/cute/flash_bwd.py`
- `flash_attn/cute/flash_bwd_postprocess.py`
- `flash_attn/cute/flash_bwd_preprocess.py`
- `flash_attn/cute/flash_bwd_sm100.py`
- `flash_attn/cute/flash_bwd_sm90.py`
- `flash_attn/cute/flash_fwd.py`
- `flash_attn/cute/flash_fwd_combine.py`
- `flash_attn/cute/flash_fwd_sm100.py`
- `flash_attn/cute/interface.py`
- `flash_attn/cute/seqlen_info.py`
- `flash_attn/cute/tile_scheduler.py`
- `tests/cute/test_flash_attn.py`

## Evidence Bundle

`evidence/pull-bundles/flash-attention/gh-1940`
