2690697caa
### What this PR does / why we need it? Reset all unused positions in `NPUModelRunner` to prevent out-of-bounds asserts in the `GatherV3` operator. Currently, in [`get_splitfuse_attn_mask`](https://github.com/vllm-project/vllm-ascend/blob/main/vllm_ascend/attention/attention.py#L124), the `position` tensor may contain values that exceed the dimensions of the attention mask, triggering a `GatherV3` boundary check failure. These invalid indices originate from stale “dirty” entries left over in `position` due to padding logic in the ACL graph. Specifically, in [`_process_reqs`](https://github.com/vllm-project/vllm-ascend/blob/main/vllm_ascend/worker/model_runner_v1.py#L989), the variable `num_input_tokens` is always greater than or equal to `total_num_scheduled_tokens`, so any positions not explicitly cleared from a previous batch will persist and cause this sporadic error. BTW, in the original vLLM implementation, masks are constructed internally using other args, so these lingering values do not surface. However, on the Ascend platform—where split-fuse attention requires externally supplied masks—these residual indices become critical and lead to this elusive, hard-to-reproduce failure. The fix is to explicitly reset or zero out all unused entries in the `position` tensor before passing it to `GatherV3`, ensuring that every index lies within the valid range of the attention mask. Closes: https://github.com/vllm-project/vllm-ascend/issues/1038 ### Does this PR introduce _any_ user-facing change? No Signed-off-by: Yizhou Liu <liu_yizhou@outlook.com>
vLLM Ascend Plugin
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English | 中文
Latest News 🔥
- [2025/03] We hosted the vLLM Beijing Meetup with vLLM team! Please find the meetup slides here.
- [2025/02] vLLM community officially created vllm-project/vllm-ascend repo for running vLLM seamlessly on the Ascend NPU.
- [2024/12] We are working with the vLLM community to support [RFC]: Hardware pluggable.
Overview
vLLM Ascend (vllm-ascend) is a community maintained hardware plugin for running vLLM seamlessly on the Ascend NPU.
It is the recommended approach for supporting the Ascend backend within the vLLM community. It adheres to the principles outlined in the [RFC]: Hardware pluggable, providing a hardware-pluggable interface that decouples the integration of the Ascend NPU with vLLM.
By using vLLM Ascend plugin, popular open-source models, including Transformer-like, Mixture-of-Expert, Embedding, Multi-modal LLMs can run seamlessly on the Ascend NPU.
Prerequisites
- Hardware: Atlas 800I A2 Inference series, Atlas A2 Training series
- OS: Linux
- Software:
- Python >= 3.9, < 3.12
- CANN >= 8.1.RC1
- PyTorch >= 2.5.1, torch-npu >= 2.5.1.post1.dev20250619
- vLLM (the same version as vllm-ascend)
Getting Started
Please refer to QuickStart and Installation for more details.
Contributing
See CONTRIBUTING for more details, which is a step-by-step guide to help you set up development environment, build and test.
We welcome and value any contributions and collaborations:
- Please let us know if you encounter a bug by filing an issue
- Please use User forum for usage questions and help.
Branch
vllm-ascend has main branch and dev branch.
- main: main branch，corresponds to the vLLM main branch, and is continuously monitored for quality through Ascend CI.
- vX.Y.Z-dev: development branch, created with part of new releases of vLLM. For example,
v0.7.3-devis the dev branch for vLLMv0.7.3version.
Below is maintained branches:
| Branch | Status | Note |
|---|---|---|
| main | Maintained | CI commitment for vLLM main branch and vLLM 0.9.x branch |
| v0.7.1-dev | Unmaintained | Only doc fixed is allowed |
| v0.7.3-dev | Maintained | CI commitment for vLLM 0.7.3 version |
Please refer to Versioning policy for more details.
Weekly Meeting
- vLLM Ascend Weekly Meeting: https://tinyurl.com/vllm-ascend-meeting
- Wednesday, 15:00 - 16:00 (UTC+8, Convert to your timezone)
License
Apache License 2.0, as found in the LICENSE file.