[BUG] multi gpu training without --single_gpu

[menatallh]

Describe the bug Problem with multi gpu training when i remove --single gpu

Expected behavior it detects the available gpus

Screenshots

System Info:

• OS: [e.g. Ubuntu 18.04]
• Python version [e.g. 3.8.6]
• PyTorch version [e.g. 1.7.0+cu11]

Additional context Add any other context about the problem here.

[simon-ging]

If you have solved it, please consider posting your fix for others.

[menggehe]

Did you solve this problem?

[simon-ging]

Does it still happen? If yes please post a complete bug report: Which command do you input, the complete error message, output of system command "nvidia-smi", which system / python / pytorch version. Then I will look into it.

[menggehe]

command :

message：

output of system command "nvidia-smi"：

System Info: OS: Ubuntu 18.04 Python version 3.8.5 PyTorch version 1.8.1

[menggehe]

I change some code in utils_torch.py: 1. before: after:

But the model still uses only one GPU device:0.

[simon-ging]

I will check this problem, it should be possible to train on multiple GPUs. Other than that, unless you increase the model size or batch size, a single 12GB GPU is more than enough to train retrieval