Pytorch 多 GPU 问题

Question

I want to train my model with 2 GPU(id 5, 6), so I run my code with CUDA_VISIBLE_DEVICES=5,6 train.py . However, when I printed torch.cuda.current_device I still got the id 0 rather than 5,6. But torch.cuda.device_count is 2 , which semms right. How can I use GPU5,6 correctly?

Answer 1

It is most likely correct. PyTorch only sees two GPUs (therefore indexed 0 and 1) which are actually your GPU 5 and 6.

Check the actual usage with nvidia-smi . If it is still inconsistent, you might need to set an environment variable:

export CUDA_DEVICE_ORDER=PCI_BUS_ID

(See Inconsistency of IDs between 'nvidia-smi -L' and cuDeviceGetName() )

Answer 2

you can check the device name to verify whether that is the correct name of that GPU. However, I think when you set the Cuda_Visible outside, you have forced torch to look only at that 2 gpu. So torch will manually set index for them as 0 and 1. Because of this, when you check the current_device, it will output 0