How does CUDA assign device IDs to GPUs?

Question

When a computer has multiple CUDA-capable GPUs, each GPU is assigned a device ID. By default, CUDA kernels execute on device ID 0. You can use

Answer 1

Set the environment variable CUDA_DEVICE_ORDER as:

export CUDA_DEVICE_ORDER=PCI_BUS_ID

Then the GPU IDs will be ordered by pci bus IDs.