---
id: pr-sglang-5476
repo: sgl-project/sglang
pr: 5476
title: Avoid computing lse in Ragged Prefill when there's no prefix.
author: Edenzzzz
date: '2025-04-18'
url: https://github.com/sgl-project/sglang/pull/5476
source_category: upstream-code
architectures:
- sm100
tags:
- attention
- mla
- prefill
techniques: []
hardware_features: []
kernel_types:
- attention
- mla
- prefill
languages:
- python
captured_at: '2026-04-27'
status: merged
merge_sha: bfa392245159147a2b7dbd67178c825e5035c329
inclusion_reason: kernel file changes
changed_paths:
- docs/backend/server_arguments.md
- python/sglang/srt/layers/attention/flashinfer_backend.py
- python/sglang/srt/layers/attention/flashinfer_mla_backend.py
head_ref_oid: a1b373c314ad7404e199144134fc7f8b1015866a
artifact_dir: evidence/pull-bundles/sglang/gh-5476
---
# Avoid computing lse in Ragged Prefill when there's no prefix.

- Repository: `sgl-project/sglang`
- PR: [5476](https://github.com/sgl-project/sglang/pull/5476)
- Decision: `kernel file changes`
- Reason: kernel file changes

## Changed Paths

- `docs/backend/server_arguments.md`
- `python/sglang/srt/layers/attention/flashinfer_backend.py`
- `python/sglang/srt/layers/attention/flashinfer_mla_backend.py`

## Evidence Bundle

`evidence/pull-bundles/sglang/gh-5476`
