---
id: pr-sglang-21440
repo: sgl-project/sglang
pr: 21440
title: '[Diffusion] Add qknorm rope fuse kernel'
author: BBuf
date: '2026-03-27'
url: https://github.com/sgl-project/sglang/pull/21440
source_category: upstream-code
architectures:
- sm100
tags:
- benchmark_test
- compiler_runtime
- fused norm
- norm_elementwise
techniques:
- kernel-fusion
hardware_features: []
kernel_types:
- compiler
- norm
languages:
- cuda-cpp
captured_at: '2026-05-16'
status: merged
merge_sha: d633ab7349a8cdfe939d25745c3f647c508b8be5
inclusion_reason: Look for fusion, vectorization, dtype conversion, and store-traffic reductions before changing math.
changed_paths:
- python/sglang/jit_kernel/benchmark/diffusion/bench_qknorm_rope.py
- python/sglang/jit_kernel/csrc/diffusion/qknorm_rope.cuh
- python/sglang/jit_kernel/diffusion/qknorm_rope.py
- python/sglang/jit_kernel/tests/diffusion/test_qknorm_rope.py
- python/sglang/multimodal_gen/runtime/layers/layernorm.py
- python/sglang/multimodal_gen/runtime/models/dits/flux.py
- python/sglang/multimodal_gen/runtime/models/dits/flux_2.py
- python/sglang/multimodal_gen/runtime/models/dits/qwen_image.py
- python/sglang/multimodal_gen/runtime/models/dits/zimage.py
artifact_dir: evidence/pull-bundles/sglang/gh-21440
head_ref_oid: e10d25550654e4e099a04d1f47816c8c42fd1bf8
---
# [Diffusion] Add qknorm rope fuse kernel

- Repository: `sgl-project/sglang`
- PR: [21440](https://github.com/sgl-project/sglang/pull/21440)
- 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

- `python/sglang/jit_kernel/benchmark/diffusion/bench_qknorm_rope.py`
- `python/sglang/jit_kernel/csrc/diffusion/qknorm_rope.cuh`
- `python/sglang/jit_kernel/diffusion/qknorm_rope.py`
- `python/sglang/jit_kernel/tests/diffusion/test_qknorm_rope.py`
- `python/sglang/multimodal_gen/runtime/layers/layernorm.py`
- `python/sglang/multimodal_gen/runtime/models/dits/flux.py`
- `python/sglang/multimodal_gen/runtime/models/dits/flux_2.py`
- `python/sglang/multimodal_gen/runtime/models/dits/qwen_image.py`
- `python/sglang/multimodal_gen/runtime/models/dits/zimage.py`

## Evidence Bundle

`evidence/pull-bundles/sglang/gh-21440`
