---
id: pr-vllm-29795
repo: vllm-project/vllm
pr: 29795
title: '[Perf] Improve fp8 quant in mla; replace ReduceSum with ReduceScatterSum'
author: IwakuraRein
date: '2025-12-08'
url: https://github.com/vllm-project/vllm/pull/29795
source_category: upstream-code
architectures:
- sm100
- sm90
tags:
- attention
- fp8
- mla
techniques: []
hardware_features:
- fp8
kernel_types:
- attention
- mla
languages:
- cuda-cpp
captured_at: '2026-04-27'
status: merged
merge_sha: 1fb632fdb6b6391cd1fe3146d05cc2858c2446ab
inclusion_reason: kernel file changes
changed_paths:
- vllm/distributed/device_communicators/cuda_communicator.py
- vllm/v1/attention/backends/mla/common.py
head_ref_oid: e654cd1b5639fb1ed7c44be29aa40258d12f4edc
artifact_dir: evidence/pull-bundles/vllm/gh-29795
---
# [Perf] Improve fp8 quant in mla; replace ReduceSum with ReduceScatterSum

- Repository: `vllm-project/vllm`
- PR: [29795](https://github.com/vllm-project/vllm/pull/29795)
- Decision: `kernel file changes`
- Reason: kernel file changes

## Changed Paths

- `vllm/distributed/device_communicators/cuda_communicator.py`
- `vllm/v1/attention/backends/mla/common.py`

## Evidence Bundle

`evidence/pull-bundles/vllm/gh-29795`
