---
id: pr-flashinfer-1685
repo: flashinfer-ai/flashinfer
pr: 1685
title: 'perf: Port the separate reduce kernel mode from trtllm.'
author: weireweire
date: '2025-09-19'
url: https://github.com/flashinfer-ai/flashinfer/pull/1685
source_category: upstream-code
architectures:
- sm100
tags:
- attention
- flash-attention
techniques: []
hardware_features: []
kernel_types:
- attention
- flash-attention
languages:
- cuda-cpp
captured_at: '2026-04-27'
status: merged
merge_sha: ed1d8c1461d8cf85bd6d1c2f46eb4fbf4b14aa1a
inclusion_reason: kernel file changes
changed_paths:
- csrc/fmhaReduction.cu
- flashinfer/artifacts.py
- flashinfer/jit/attention/pytorch.py
- include/flashinfer/trtllm/common/cudaUtils.h
- include/flashinfer/trtllm/fmha/fmhaKernels.cuh
- include/flashinfer/trtllm/fmha/fmhaReduction.h
- include/flashinfer/trtllm/fmha/fmhaRunnerParams.h
- include/flashinfer/trtllm/fmha/kernelUtils.h
- tests/test_attention_sink_blackwell.py
head_ref_oid: d036d318dc6c82d186b65341558de0e7adde617c
artifact_dir: evidence/pull-bundles/flashinfer/gh-1685
---
# perf: Port the separate reduce kernel mode from trtllm.

- Repository: `flashinfer-ai/flashinfer`
- PR: [1685](https://github.com/flashinfer-ai/flashinfer/pull/1685)
- Decision: `kernel file changes`
- Reason: kernel file changes

## Changed Paths

- `csrc/fmhaReduction.cu`
- `flashinfer/artifacts.py`
- `flashinfer/jit/attention/pytorch.py`
- `include/flashinfer/trtllm/common/cudaUtils.h`
- `include/flashinfer/trtllm/fmha/fmhaKernels.cuh`
- `include/flashinfer/trtllm/fmha/fmhaReduction.h`
- `include/flashinfer/trtllm/fmha/fmhaRunnerParams.h`
- `include/flashinfer/trtllm/fmha/kernelUtils.h`
- `tests/test_attention_sink_blackwell.py`

## Evidence Bundle

`evidence/pull-bundles/flashinfer/gh-1685`
