---
id: pr-vllm-42153
repo: vllm-project/vllm
pr: 42153
title: '[Perf] Use 2D-grid to eliminate divmod in W8W8 group quant'
author: jiahanc
date: '2026-05-12'
url: https://github.com/vllm-project/vllm/pull/42153
source_category: upstream-code
architectures:
- sm100
tags:
- benchmark kernel
- benchmark_test
- gemm_quant
- quantization kernel
techniques:
- fine-grained-quantization
hardware_features:
- fp8
kernel_types:
- gemm
languages:
- cuda-cpp
captured_at: '2026-05-16'
status: merged
merge_sha: dd6b3a5ef548e9349e6c103dfa7b1b484c9ca41a
inclusion_reason: Inspect scale layout, accumulator type, tile/schedule choice, epilogue fusion, and partial-tile guards before deriving a candidate.
changed_paths:
- csrc/libtorch_stable/quantization/w8a8/fp8/per_token_group_quant.cu
artifact_dir: evidence/pull-bundles/vllm/gh-42153
head_ref_oid: cebe43dc8fed8810144358206c0d0589cec8e9bf
---
# [Perf] Use 2D-grid to eliminate divmod in W8W8 group quant

- Repository: `vllm-project/vllm`
- PR: [42153](https://github.com/vllm-project/vllm/pull/42153)
- 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

- `csrc/libtorch_stable/quantization/w8a8/fp8/per_token_group_quant.cu`

## Evidence Bundle

`evidence/pull-bundles/vllm/gh-42153`
