---
id: pr-flashinfer-1850
repo: flashinfer-ai/flashinfer
pr: 1850
title: Add head_dim=64 for blackwell cutlass fmha implementation
author: kahyunnam
date: '2025-10-03'
url: https://github.com/flashinfer-ai/flashinfer/pull/1850
source_category: upstream-code
architectures:
- sm100
tags:
- tcgen05
- flash-attention
- attention
techniques:
- warp-specialization
- persistent-kernel
- pipeline-stages
hardware_features:
- tcgen05
- tmem
- tma
kernel_types:
- flash-attention
- attention
- prefill
languages:
- cuda-cpp
captured_at: 2026-04-16
status: merged
merge_sha: f3ea938dbb22aab2127e89f6265d4be83431537f
inclusion_reason: manually curated, Blackwell kernel relevance
changed_paths:
- benchmarks/bench_blackwell_attention.py
- csrc/fmha_cutlass_sm100.cu
- include/flashinfer/attention/blackwell/collective/sm100_fmha_fwd_mainloop_tma_warpspecialized.hpp
- include/flashinfer/attention/blackwell/collective/sm100_fmha_gen_mainloop_warpspecialized.hpp
- tests/attention/test_blackwell_fmha.py
artifact_dir: evidence/pull-bundles/flashinfer/gh-1850
head_ref_oid: a0244d7d56bc0814e92953ca93ca6c3daa3bc6fe
---
# Add head_dim=64 for blackwell cutlass fmha implementation

- Repository: `flashinfer-ai/flashinfer`
- PR: [1850](https://github.com/flashinfer-ai/flashinfer/pull/1850)
- Decision: `manually curated, Blackwell kernel relevance`
- Reason: manually curated, Blackwell kernel relevance

## Changed Paths

- `benchmarks/bench_blackwell_attention.py`
- `csrc/fmha_cutlass_sm100.cu`
- `include/flashinfer/attention/blackwell/collective/sm100_fmha_fwd_mainloop_tma_warpspecialized.hpp`
- `include/flashinfer/attention/blackwell/collective/sm100_fmha_gen_mainloop_warpspecialized.hpp`
- `tests/attention/test_blackwell_fmha.py`

## Evidence Bundle

`evidence/pull-bundles/flashinfer/gh-1850`
