---
id: pr-vllm-34917
repo: vllm-project/vllm
pr: 34917
title: '[Attention][Perf][Kernel] Replace torch.cat with vectorized CUDA kernel MLA query concat - DeepSeek-V3.2'
author: LopezCastroRoberto
date: '2026-03-09'
url: https://github.com/vllm-project/vllm/pull/34917
source_category: upstream-code
architectures:
- sm100
tags:
- attention
- mla
techniques: []
hardware_features: []
kernel_types:
- attention
- mla
languages:
- cuda-cpp
captured_at: '2026-04-27'
status: merged
merge_sha: 580864d81eb03d9fb1383e1782636ff6a9425fa2
inclusion_reason: kernel file changes
changed_paths:
- .buildkite/test_areas/kernels.yaml
- benchmarks/kernels/bench_concat_mla_q.py
- csrc/cache.h
- csrc/cache_kernels.cu
- csrc/concat_mla_q.cuh
- csrc/cuda_vec_utils.cuh
- csrc/torch_bindings.cpp
- tests/kernels/test_concat_mla_q.py
- vllm/_custom_ops.py
- vllm/v1/attention/backends/mla/flashmla_sparse.py
head_ref_oid: 43dffba1abd23a3ce8e8005e58a4427f26ee6194
artifact_dir: evidence/pull-bundles/vllm/gh-34917
---
# [Attention][Perf][Kernel] Replace torch.cat with vectorized CUDA kernel MLA query concat - DeepSeek-V3.2

- Repository: `vllm-project/vllm`
- PR: [34917](https://github.com/vllm-project/vllm/pull/34917)
- Decision: `kernel file changes`
- Reason: kernel file changes

## Changed Paths

- `.buildkite/test_areas/kernels.yaml`
- `benchmarks/kernels/bench_concat_mla_q.py`
- `csrc/cache.h`
- `csrc/cache_kernels.cu`
- `csrc/concat_mla_q.cuh`
- `csrc/cuda_vec_utils.cuh`
- `csrc/torch_bindings.cpp`
- `tests/kernels/test_concat_mla_q.py`
- `vllm/_custom_ops.py`
- `vllm/v1/attention/backends/mla/flashmla_sparse.py`

## Evidence Bundle

`evidence/pull-bundles/vllm/gh-34917`
