---
id: pr-tensorrt-llm-8675
repo: NVIDIA/TensorRT-LLM
pr: 8675
title: '[TRTLLM-8827] [feat] Enable low precision alltoall for Cutlass and TRTLLMGen backends'
author: kaiyux
date: '2025-10-28'
url: https://github.com/NVIDIA/TensorRT-LLM/pull/8675
source_category: upstream-code
architectures:
- sm100
tags:
- benchmark_test
- moe_routing
- trtllmgen
techniques:
- kernel-fusion
hardware_features: []
kernel_types:
- moe
languages:
- cute-dsl
captured_at: '2026-05-16'
status: merged
merge_sha: 227c2884413d9e80cb4117f0864d89dbe5ef03f6
inclusion_reason: Separate routing, permutation, top-k, and expert GEMM costs; keep tail-token and expert-layout tests attached to the idea.
changed_paths:
- tensorrt_llm/_torch/modules/fused_moe/fused_moe_cutlass.py
- tensorrt_llm/_torch/modules/fused_moe/fused_moe_trtllm_gen.py
- tensorrt_llm/_torch/modules/fused_moe/fused_moe_wide_ep.py
- tensorrt_llm/_torch/modules/fused_moe/interface.py
- tests/unittest/_torch/modules/test_fused_moe.py
artifact_dir: evidence/pull-bundles/tensorrt-llm/gh-8675
head_ref_oid: be434244146497f2e15f98d5aab955e437b13c46
---
# [TRTLLM-8827] [feat] Enable low precision alltoall for Cutlass and TRTLLMGen backends

- Repository: `NVIDIA/TensorRT-LLM`
- PR: [8675](https://github.com/NVIDIA/TensorRT-LLM/pull/8675)
- 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

- `tensorrt_llm/_torch/modules/fused_moe/fused_moe_cutlass.py`
- `tensorrt_llm/_torch/modules/fused_moe/fused_moe_trtllm_gen.py`
- `tensorrt_llm/_torch/modules/fused_moe/fused_moe_wide_ep.py`
- `tensorrt_llm/_torch/modules/fused_moe/interface.py`
- `tests/unittest/_torch/modules/test_fused_moe.py`

## Evidence Bundle

`evidence/pull-bundles/tensorrt-llm/gh-8675`
