---
id: pr-flash-attention-2489
repo: Dao-AILab/flash-attention
pr: 2489
title: '[hd256] Add TMA paged KV support to SM100 2CTA forward kernel'
author: Johnsonms
date: '2026-05-01'
url: https://github.com/Dao-AILab/flash-attention/pull/2489
source_category: upstream-code
architectures:
- sm100
tags:
- arch_pipeline
- attention_kv
- cute
- paged
- scheduler_autotune
- sm100
- tma
- varlen
techniques:
- async-copy
- autotuning
- pipeline-stages
- tile-scheduling
hardware_features:
- blackwell
- tma
kernel_types:
- attention
- runtime
- scheduler
languages:
- cuda-cpp
- cute-dsl
captured_at: '2026-05-16'
status: merged
merge_sha: cb213fce11c3baf9168f7fa607bc7f22e3323554
inclusion_reason: Preserve page/KV/layout and plan-run contracts; profile memory traffic separately from math utilization.
changed_paths:
- flash_attn/cute/interface.py
- flash_attn/cute/paged_kv.py
- flash_attn/cute/sm100_hd256_2cta_fmha_forward.py
- tests/cute/test_flash_attn.py
artifact_dir: evidence/pull-bundles/flash-attention/gh-2489
head_ref_oid: fe44ca87a11f4dab905add9fe6aa2cc26b56a3cf
---
# [hd256] Add TMA paged KV support to SM100 2CTA forward kernel

- Repository: `Dao-AILab/flash-attention`
- PR: [2489](https://github.com/Dao-AILab/flash-attention/pull/2489)
- 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/interface.py`
- `flash_attn/cute/paged_kv.py`
- `flash_attn/cute/sm100_hd256_2cta_fmha_forward.py`
- `tests/cute/test_flash_attn.py`

## Evidence Bundle

`evidence/pull-bundles/flash-attention/gh-2489`
