---
id: pr-sglang-20606
repo: sgl-project/sglang
pr: 20606
title: 'FIX: (NSA) Compute topk_indices_offset when NSA prefill flashmla_sparse is used with FP8 KV cache'
author: JackChuang
date: '2026-03-26'
url: https://github.com/sgl-project/sglang/pull/20606
source_category: upstream-code
architectures:
- sm100
- sm90
tags:
- attention
- fp8
- mla
- prefill
techniques: []
hardware_features:
- fp8
kernel_types:
- attention
- mla
- prefill
languages:
- python
captured_at: '2026-04-17'
status: merged
merge_sha: 4b5f63e1b8ba37f26d71caf2a6004e473db53675
inclusion_reason: kernel file changes
changed_paths:
- python/sglang/srt/layers/attention/nsa_backend.py
head_ref_oid: c9dd58302bae64d56a728c2f4068218be38bb5e9
artifact_dir: evidence/pull-bundles/sglang/gh-20606
---
# FIX: (NSA) Compute topk_indices_offset when NSA prefill flashmla_sparse is used with FP8 KV cache

- Repository: `sgl-project/sglang`
- PR: [20606](https://github.com/sgl-project/sglang/pull/20606)
- Decision: `kernel file changes`
- Reason: kernel file changes

## Changed Paths

- `python/sglang/srt/layers/attention/nsa_backend.py`

## Evidence Bundle

`evidence/pull-bundles/sglang/gh-20606`
