How to enable P2P access?

[rs277]

Seems to be somewhat of a challenging process. See this thread:

RTX 3090 + NVLink + CUDA P2P - not working on Linux or Windows, in different ways?

Hello, I am using the 4-slot RTX NVLINK bridge along with two RTX 3090 cards. In both Windows and Linux, it seems that it’s not quite working (with CUDA 11.8). On Ubuntu 20.04, driver 520.61.05, nvidia-smi nvlink seems to indicate that the NVLink connections are present but down. The p2pBandwidthLatencyTest example indicates that peer-to-peer access is working … but the actual P2P bandwidth is so slow (<0.01 GB/s) that the example hangs. $ nvidia-smi topo -m GPU0 GPU1 CPU Affinity NUMA Aff…