---
license: bsd-3-clause
tags:
  - wheels
  - flash-attention
---

# Prebuilt wheels for the OPD environment

Mirror of official upstream release artifacts, re-hosted so machines with slow
GitHub access can pull them through `hf-mirror.com`. Nothing is rebuilt or
modified — byte-identical to the GitHub release assets.

## `flash_attn-2.8.3+cu12torch2.9cxx11abiTRUE-cp312-cp312-linux_x86_64.whl`

- Upstream: [Dao-AILab/flash-attention v2.8.3](https://github.com/Dao-AILab/flash-attention/releases/tag/v2.8.3)
- Size: 243 MiB
- `sha256: 4e2f9e39313266b1544b68138b15b91ee6221eccf14f7902b7c6620351340810`
- License: BSD-3-Clause (upstream)

Matches exactly one environment. All four coordinates have to line up:

| Coordinate | Value | Why it is fixed |
|---|---|---|
| torch | 2.9.0 | `vllm==0.12.0` pins `torch==2.9.0` (hard `==` in its metadata) |
| CUDA | cu12 | PyPI torch 2.9.0 is a cu128 build (`nvidia-*-cu12==12.8.x`) |
| cxx11abi | TRUE | the only variant published for torch2.9 |
| python | cp312 | the only variant published for torch2.9 — 3.10/3.11/3.13 do not exist |
| platform | linux_x86_64 | aarch64 exists upstream but is not mirrored here |

**Requires compute capability >= 8.0** (Ampere or newer). FlashAttention-2 has no
kernels for sm70 (V100). Check with
`nvidia-smi --query-gpu=compute_cap --format=csv` before bothering.

Also note it is not needed for vLLM generation at all — verl's `flash_attn`
imports live under `verl/models/*/megatron/*`, which the generation path never
touches. It is only required once FSDP KL training starts.

## Install

```bash
HF_ENDPOINT=https://hf-mirror.com hf download HzChen20/opd-wheels \
    --repo-type dataset --include "*.whl" --local-dir ./wheels

pip install ./wheels/flash_attn-2.8.3+cu12torch2.9cxx11abiTRUE-cp312-cp312-linux_x86_64.whl
python -c "import flash_attn; print(flash_attn.__version__)"
```

Verify the transfer first if the link is unreliable:

```bash
sha256sum -c <<< "4e2f9e39313266b1544b68138b15b91ee6221eccf14f7902b7c6620351340810  ./wheels/flash_attn-2.8.3+cu12torch2.9cxx11abiTRUE-cp312-cp312-linux_x86_64.whl"
```