---
id: pr-vllm-35161
repo: vllm-project/vllm
pr: 35161
title: '[Bugfix] Fix expert_ids padding values in moe_align_block_size kernel'
author: xyang16
date: '2026-02-25'
url: https://github.com/vllm-project/vllm/pull/35161
source_category: upstream-code
architectures:
- sm100
tags:
- benchmark_test
- csrc kernel
- moe_routing
techniques:
- kernel-fusion
hardware_features: []
kernel_types:
- moe
languages:
- cuda-cpp
captured_at: '2026-05-16'
status: merged
merge_sha: 3bbb2046ff320395c80c139e55e7c1947c3fb5e1
inclusion_reason: Separate routing, permutation, top-k, and expert GEMM costs; keep tail-token and expert-layout tests attached to the idea.
changed_paths:
- csrc/moe/moe_align_sum_kernels.cu
- tests/kernels/moe/test_moe_align_block_size.py
artifact_dir: evidence/pull-bundles/vllm/gh-35161
head_ref_oid: c407f85b7657640e20ad7164e204798ac81c13f7
---
# [Bugfix] Fix expert_ids padding values in moe_align_block_size kernel

- Repository: `vllm-project/vllm`
- PR: [35161](https://github.com/vllm-project/vllm/pull/35161)
- Decision: `Separate routing, permutation, top-k, and expert GEMM costs; keep tail-token and expert-layout tests attached to the idea.`
- Reason: Separate routing, permutation, top-k, and expert GEMM costs; keep tail-token and expert-layout tests attached to the idea.

## Changed Paths

- `csrc/moe/moe_align_sum_kernels.cu`
- `tests/kernels/moe/test_moe_align_block_size.py`

## Evidence Bundle

`evidence/pull-bundles/vllm/gh-35161`
