---
id: pr-vllm-11844
repo: vllm-project/vllm
pr: 11844
title: Implements dual-chunk-flash-attn backend for dual chunk attention with sparse attention support
author: sighingnow
date: '2025-05-13'
url: https://github.com/vllm-project/vllm/pull/11844
source_category: upstream-code
architectures:
- sm100
tags: []
techniques: []
hardware_features: []
kernel_types: []
languages: []
captured_at: '2026-05-16'
status: merged
merge_sha: 60f76243344d2d3deca5e5ecdade547acc7fed50
inclusion_reason: defer
changed_paths:
- CMakeLists.txt
- csrc/attention/vertical_slash_index.cu
- csrc/ops.h
- csrc/torch_bindings.cpp
- examples/offline_inference/qwen_1m.py
- vllm/_custom_ops.py
- vllm/attention/backends/dual_chunk_flash_attn.py
- vllm/config.py
- vllm/engine/arg_utils.py
- vllm/model_executor/layers/rotary_embedding.py
- vllm/model_executor/model_loader/weight_utils.py
- vllm/model_executor/models/qwen2.py
- vllm/model_executor/models/qwen2_moe.py
- vllm/platforms/cuda.py
- vllm/platforms/interface.py
- vllm/utils.py
- vllm/worker/model_runner.py
artifact_dir: evidence/pull-bundles/vllm/gh-11844
head_ref_oid: 44bf2abb2940241cb97917aedc053b949cac3002
---
# Implements dual-chunk-flash-attn backend for dual chunk attention with sparse attention support

- Repository: `vllm-project/vllm`
- PR: [11844](https://github.com/vllm-project/vllm/pull/11844)
- Decision: `defer`
- Reason: defer

## Changed Paths

- `CMakeLists.txt`
- `csrc/attention/vertical_slash_index.cu`
- `csrc/ops.h`
- `csrc/torch_bindings.cpp`
- `examples/offline_inference/qwen_1m.py`
- `vllm/_custom_ops.py`
- `vllm/attention/backends/dual_chunk_flash_attn.py`
- `vllm/config.py`
- `vllm/engine/arg_utils.py`
- `vllm/model_executor/layers/rotary_embedding.py`
- `vllm/model_executor/model_loader/weight_utils.py`
- `vllm/model_executor/models/qwen2.py`
- `vllm/model_executor/models/qwen2_moe.py`
- `vllm/platforms/cuda.py`
- `vllm/platforms/interface.py`
- `vllm/utils.py`
- `vllm/worker/model_runner.py`

## Evidence Bundle

`evidence/pull-bundles/vllm/gh-11844`
