---
id: pr-vllm-29710
repo: vllm-project/vllm
pr: 29710
title: '[perf] Use direct copy (broadcast) instead of cat for k_nope/k_pe in MLA prefill'
author: minosfuture
date: '2025-12-11'
url: https://github.com/vllm-project/vllm/pull/29710
source_category: upstream-code
architectures:
- sm100
tags:
- attention
- mla
- prefill
techniques: []
hardware_features: []
kernel_types:
- attention
- mla
- prefill
languages:
- python
captured_at: '2026-04-27'
status: merged
merge_sha: fba89069302e9b4d0457bc8eeddeeec76f27f0b1
inclusion_reason: kernel file changes
changed_paths:
- benchmarks/kernels/benchmark_mla_k_concat.py
- vllm/v1/attention/backends/mla/common.py
head_ref_oid: d2709220d9b618a08bdc9e37ae75b61708287854
artifact_dir: evidence/pull-bundles/vllm/gh-29710
---
# [perf] Use direct copy (broadcast) instead of cat for k_nope/k_pe in MLA prefill

- Repository: `vllm-project/vllm`
- PR: [29710](https://github.com/vllm-project/vllm/pull/29710)
- Decision: `kernel file changes`
- Reason: kernel file changes

## Changed Paths

- `benchmarks/kernels/benchmark_mla_k_concat.py`
- `vllm/v1/attention/backends/mla/common.py`

## Evidence Bundle

`evidence/pull-bundles/vllm/gh-29710`
