---
id: pr-flash-attention-2333
repo: Dao-AILab/flash-attention
pr: 2333
title: Add SM120 varlen attention support
author: blake-snc
date: '2026-03-13'
url: https://github.com/Dao-AILab/flash-attention/pull/2333
source_category: upstream-code
architectures:
- sm100
- sm90
tags:
- arch_pipeline
- attention_kv
- blackwell
- compiler_runtime
- scheduler_autotune
- sm90
- varlen
techniques:
- autotuning
- pipeline-stages
- tile-scheduling
hardware_features:
- blackwell
- hopper
kernel_types:
- attention
- compiler
- runtime
- scheduler
languages:
- cute-dsl
captured_at: '2026-05-16'
status: merged
merge_sha: 4c8e5ee28e7f22acb1a07c95009dc80e4a80fb4d
inclusion_reason: Preserve page/KV/layout and plan-run contracts; profile memory traffic separately from math utilization.
changed_paths:
- flash_attn/cute/flash_fwd.py
artifact_dir: evidence/pull-bundles/flash-attention/gh-2333
head_ref_oid: 74e13f831cbcc54edf7197216826e04678ccecdf
---
# Add SM120 varlen attention support

- Repository: `Dao-AILab/flash-attention`
- PR: [2333](https://github.com/Dao-AILab/flash-attention/pull/2333)
- 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

- `flash_attn/cute/flash_fwd.py`

## Evidence Bundle

`evidence/pull-bundles/flash-attention/gh-2333`
