---
id: pr-vllm-42236
repo: vllm-project/vllm
pr: 42236
title: '[DSv4] Improved dequant gather K cache kernel'
author: gau-nernst
date: '2026-05-11'
url: https://github.com/vllm-project/vllm/pull/42236
source_category: upstream-code
architectures:
- sm90
tags:
- CUDA kernel
- attention_kv
- benchmark_test
- compiler_runtime
- fp8
- gemm_quant
- hopper
- memory_primitives
- sm90
techniques:
- cache-policy
- fine-grained-quantization
- kernel-fusion
hardware_features:
- fp8
- hopper
kernel_types:
- attention
- compiler
- gemm
- memory
languages:
- cuda-cpp
- cute-dsl
captured_at: '2026-05-16'
status: merged
merge_sha: 724ed2fc352bb388aea7269ca5c6690637c30ce7
inclusion_reason: Inspect scale layout, accumulator type, tile/schedule choice, epilogue fusion, and partial-tile guards before deriving a candidate.
changed_paths:
- tests/kernels/test_compressor_kv_cache.py
- vllm/v1/attention/ops/deepseek_v4_ops/cache_utils.py
- vllm/v1/attention/ops/deepseek_v4_ops/cutedsl_utils.py
- vllm/v1/attention/ops/deepseek_v4_ops/dequant_gather_k_cutedsl.py
- vllm/v1/attention/ops/deepseek_v4_ops/fused_indexer_q_cutedsl.py
artifact_dir: evidence/pull-bundles/vllm/gh-42236
head_ref_oid: 830f3808ea91bf0e0898f33cdd2faabd4bd9ade1
---
# [DSv4] Improved dequant gather K cache kernel

- Repository: `vllm-project/vllm`
- PR: [42236](https://github.com/vllm-project/vllm/pull/42236)
- Decision: `Inspect scale layout, accumulator type, tile/schedule choice, epilogue fusion, and partial-tile guards before deriving a candidate.`
- Reason: Inspect scale layout, accumulator type, tile/schedule choice, epilogue fusion, and partial-tile guards before deriving a candidate.

## Changed Paths

- `tests/kernels/test_compressor_kv_cache.py`
- `vllm/v1/attention/ops/deepseek_v4_ops/cache_utils.py`
- `vllm/v1/attention/ops/deepseek_v4_ops/cutedsl_utils.py`
- `vllm/v1/attention/ops/deepseek_v4_ops/dequant_gather_k_cutedsl.py`
- `vllm/v1/attention/ops/deepseek_v4_ops/fused_indexer_q_cutedsl.py`

## Evidence Bundle

`evidence/pull-bundles/vllm/gh-42236`
