---
id: pr-flashinfer-3157
repo: flashinfer-ai/flashinfer
pr: 3157
title: 'feat: DiT layer norm fusions for WAN: flashinfer.diffusion_ops'
author: kahyunnam
date: '2026-05-01'
url: https://github.com/flashinfer-ai/flashinfer/pull/3157
source_category: upstream-code
architectures:
- sm100
- sm90
tags:
- attention_kv
- benchmark
- benchmark_test
- blackwell
- cuda kernel
- gemm_quant
- hopper
- mxfp4
- norm_elementwise
- nvfp4
- sm100
- sm90
techniques:
- fine-grained-quantization
- kernel-fusion
hardware_features:
- blackwell
- fp4
- hopper
- mxfp4
- nvfp4
kernel_types:
- attention
- gemm
- norm
languages:
- cuda-cpp
captured_at: '2026-05-16'
status: merged
merge_sha: 68d2b66ac1d5676ae637c85577e65f384506c858
inclusion_reason: Look for fusion, vectorization, dtype conversion, and store-traffic reductions before changing math.
changed_paths:
- benchmarks/bench_fused_dit_layernorm.py
- benchmarks/routines/flashinfer_benchmark_utils.py
- benchmarks/routines/norm.py
- csrc/flashinfer_norm_binding.cu
- csrc/norm.cu
- flashinfer/diffusion_ops/__init__.py
- flashinfer/norm/__init__.py
- include/flashinfer/norm/fused_dit_layernorm.cuh
- tests/norm/test_fused_dit_layernorm.py
artifact_dir: evidence/pull-bundles/flashinfer/gh-3157
head_ref_oid: 252c638030bc3966db017a7eb2fed83c5fc50059
---
# feat: DiT layer norm fusions for WAN: flashinfer.diffusion_ops

- Repository: `flashinfer-ai/flashinfer`
- PR: [3157](https://github.com/flashinfer-ai/flashinfer/pull/3157)
- Decision: `Look for fusion, vectorization, dtype conversion, and store-traffic reductions before changing math.`
- Reason: Look for fusion, vectorization, dtype conversion, and store-traffic reductions before changing math.

## Changed Paths

- `benchmarks/bench_fused_dit_layernorm.py`
- `benchmarks/routines/flashinfer_benchmark_utils.py`
- `benchmarks/routines/norm.py`
- `csrc/flashinfer_norm_binding.cu`
- `csrc/norm.cu`
- `flashinfer/diffusion_ops/__init__.py`
- `flashinfer/norm/__init__.py`
- `include/flashinfer/norm/fused_dit_layernorm.cuh`
- `tests/norm/test_fused_dit_layernorm.py`

## Evidence Bundle

`evidence/pull-bundles/flashinfer/gh-3157`
