nvidia-smi topo -m
        GPU0    GPU1    GPU2    GPU3    GPU4    GPU5    GPU6    GPU7    mlx5_0  CPU Affinity
GPU0     X      NV1     NV1     NV2     NV2     SYS     SYS     SYS     NODE    0-11,24-35
GPU1    NV1      X      NV2     NV1     SYS     NV2     SYS     SYS     NODE    0-11,24-35
GPU2    NV1     NV2      X      NV2     SYS     SYS     NV1     SYS     PIX     0-11,24-35
GPU3    NV2     NV1     NV2      X      SYS     SYS     SYS     NV1     PIX     0-11,24-35
GPU4    NV2     SYS     SYS     SYS      X      NV1     NV1     NV2     SYS     12-23,36-47
GPU5    SYS     NV2     SYS     SYS     NV1      X      NV2     NV1     SYS     12-23,36-47
GPU6    SYS     SYS     NV1     SYS     NV1     NV2      X      NV2     SYS     12-23,36-47
GPU7    SYS     SYS     SYS     NV1     NV2     NV1     NV2      X      SYS     12-23,36-47
mlx5_0  NODE    NODE    PIX     PIX     SYS     SYS     SYS     SYS      X

Legend:

  X    = Self
  SYS  = Connection traversing PCIe as well as the SMP interconnect between NUMA nodes (e.g., QPI/UPI)
  NODE = Connection traversing PCIe as well as the interconnect between PCIe Host Bridges within a NUMA node
  PHB  = Connection traversing PCIe as well as a PCIe Host Bridge (typically the CPU)
  PXB  = Connection traversing multiple PCIe bridges (without traversing the PCIe Host Bridge)
  PIX  = Connection traversing at most a single PCIe bridge
  NV#  = Connection traversing a bonded set of # NVLinks