nvidia-smi does not make use of NVLink even though the NVSwitches are shown as connected devices

Issue: Running lspci grep | NVIDIA contains NVSwitches in the output but verifying it via nvidia-smi topo -m doesn’t show them. Most probably, the installation of NVIDIA Fabric Manager is missing.

Workaround:

• Install the correct version of NVIDIA Fabric Manager. It is identical with the one you are using for NVIDIA drivers:
  sudo apt-get update
sudo apt-get -y install cuda-drivers-fabricmanager-<DRIVER_VERSION_NUMBER>
sudo systemctl enable nvidia-fabricmanager
  

• Running nvidia-smi topo -m should now display NVLink support.