常见问题¶

CUDA版本低¶

$ pip install flash_attn==2.5.8
Collecting flash_attn==2.5.8
  Downloading http://mirrors.tencentyun.com/pypi/packages/72/94/06f618bb338ec7203b48ac542e73087362b7750f9c568b13d213a3f181bb/flash_attn-2.5.8.tar.gz (2.5 MB)
     ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ 2.5/2.5 MB 3.5 MB/s eta 0:00:00
  Preparing metadata (setup.py) ... error
  error: subprocess-exited-with-error

  × python setup.py egg_info did not run successfully.
  │ exit code: 1
  ╰─> [12 lines of output]
      fatal: not a git repository (or any of the parent directories): .git
      Traceback (most recent call last):
        File "<string>", line 2, in <module>
        File "<pip-setuptools-caller>", line 34, in <module>
        File "/tmp/pip-install-_1_7_f40/flash-attn_025e23eb3d9444449dca3b9e8cf9e649/setup.py", line 115, in <module>
          raise RuntimeError(
      RuntimeError: FlashAttention is only supported on CUDA 11.6 and above.  Note: make sure nvcc has a supported version by running nvcc -V.


      torch.__version__  = 2.3.0+cu121


      [end of output]

  note: This error originates from a subprocess, and is likely not a problem with pip.
error: metadata-generation-failed

× Encountered error while generating package metadata.
╰─> See above for output.

note: This is an issue with the package mentioned above, not pip.

问题定位:

$ nvcc -V
nvcc: NVIDIA (R) Cuda compiler driver
Copyright (c) 2005-2021 NVIDIA Corporation
Built on Thu_Nov_18_09:45:30_PST_2021
Cuda compilation tools, release 11.5, V11.5.119
Build cuda_11.5.r11.5/compiler.30672275_0


$ nvidia-smi
Tue Aug 27 15:33:45 2024
+---------------------------------------------------------------------------------------+
| NVIDIA-SMI 535.183.01             Driver Version: 535.183.01   CUDA Version: 12.2     |
|-----------------------------------------+----------------------+----------------------+

分析:

机器支持的最大cuda版本是12.2，现在用的是11.5不满足flash_attn需要的11.6
结论: 升级下cuda驱动

安装:

# 卸载现有 CUDA 版本
sudo apt-get --purge remove "*cublas*" "cuda*"
sudo apt-get autoremove


# 打开Nvidia网站:
https://developer.nvidia.com/cuda-downloads

# 安装命令:
wget https://developer.download.nvidia.com/compute/cuda/repos/ubuntu2204/x86_64/cuda-keyring_1.1-1_all.deb
sudo dpkg -i cuda-keyring_1.1-1_all.deb
sudo apt-get update
sudo apt-get -y install cuda-toolkit-12-6

# 安装地址
ls /usr/local/cuda/bin/nvcc