---
id: pr-flash-attention-2388
repo: Dao-AILab/flash-attention
pr: 2388
title: 'fix: use LSE accum strides from params instead of hardcoded ones'
author: ZeronSix
date: '2026-03-25'
url: https://github.com/Dao-AILab/flash-attention/pull/2388
source_category: upstream-code
architectures:
- sm90
tags:
- arch_pipeline
- attention_kv
- recent-kernel-path
techniques:
- pipeline-stages
hardware_features:
- hopper
kernel_types:
- attention
- runtime
languages:
- cuda-cpp
captured_at: '2026-05-16'
status: merged
merge_sha: 28ef22c99a135b234fb54bc33cfb638078bacb65
inclusion_reason: Preserve page/KV/layout and plan-run contracts; profile memory traffic separately from math utilization.
changed_paths:
- hopper/flash_fwd_launch_template.h
artifact_dir: evidence/pull-bundles/flash-attention/gh-2388
head_ref_oid: e0a72b7b7f686500a48203e7c808e68fe568c3e3
---
# fix: use LSE accum strides from params instead of hardcoded ones

- Repository: `Dao-AILab/flash-attention`
- PR: [2388](https://github.com/Dao-AILab/flash-attention/pull/2388)
- Decision: `Preserve page/KV/layout and plan-run contracts; profile memory traffic separately from math utilization.`
- Reason: Preserve page/KV/layout and plan-run contracts; profile memory traffic separately from math utilization.

## Changed Paths

- `hopper/flash_fwd_launch_template.h`

## Evidence Bundle

`evidence/pull-bundles/flash-attention/gh-2388`
