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Why would you want to do Linux Guest with Linux host for CUDA?

by pavanky 10y ago

jbmorgado 10y ago
Because it's (well, at least 6 months ago was, now it could have improved) the only solution to reuse the GPU without rebooting X. With a practical example: 1 - You boot up your Linux base system. 2 - You fire up KVM with GPU PCI passthrough with a Windows guest to play some games. 3 - You shutdown windows. Now you can't use the GPU anymore, the module was assigned by KVM and you can't - for instance - run a CUDA simulation in the Linux host. You need to reboot X (you don't need to reboot the system). The workaround/solution is to fire up KVM with GPU PCI passthrough to another guest (This time a Linux guest) and in there you will have full access to the GPU to do CUDA computations (or whatever else you want).
- pavanky 10y ago
  Ah I see, that makes more sense. If you had two NVIDIA GPUs while one of them was passed through to a guest then I think that problem may still exist. However if you only have one nvidia gpu (and have a different kind of gpu for display), then I think simply running "sudo rmmod vfio" "sudo modprobe nvidia" would work.
- pYQAJ6Zm 10y ago
  >Now you can't use the GPU anymore, the module was assigned by KVM and you can't - for instance - run a CUDA simulation in the Linux host. Maybe we had different setups, so this wouldn’t apply – I used to unbind the device with the following script, and then load the `nvidia` module; the device was then available on the host: for dev in "0000:01:00.0" "0000:01:00.1"; do if [ -e /sys/bus/pci/devices/${dev}/driver ]; then echo "${dev}" > /sys/bus/pci/devices/${dev}/driver/unbind fi done
qnaal 10y ago
wintermute
pYQAJ6Zm 10y ago
One reason is to mix AMD and NVIDIA GPUs – I experimented with running X on the integrated Radeon device, while running CUDA on a Linux guest with GPU-passthrough. Trying to have CUDA on the host system led to library conflicts.

Why would you want to do Linux Guest with Linux host for CUDA?

by pavanky 10y ago

Why would you want to do Linux Guest with Linux host for CUDA?

Because it's (well, at least 6 months ago was, now it could have improved) the only solution to reuse the GPU without rebooting X. With a practical example: 1 - You boot up your Linux base system. 2 - You fire up KVM with GPU PCI passthrough with a Windows guest to play some games. 3 - You shutdown windows. Now you can't use the GPU anymore, the module was assigned by KVM and you can't - for instance - run a CUDA simulation in the Linux host. You need to reboot X (you don't need to reboot the system). The workaround/solution is to fire up KVM with GPU PCI passthrough to another guest (This time a Linux guest) and in there you will have full access to the GPU to do CUDA computations (or whatever else you want).

pavanky 10y ago
Ah I see, that makes more sense. If you had two NVIDIA GPUs while one of them was passed through to a guest then I think that problem may still exist. However if you only have one nvidia gpu (and have a different kind of gpu for display), then I think simply running "sudo rmmod vfio" "sudo modprobe nvidia" would work.
pYQAJ6Zm 10y ago
>Now you can't use the GPU anymore, the module was assigned by KVM and you can't - for instance - run a CUDA simulation in the Linux host. Maybe we had different setups, so this wouldn’t apply – I used to unbind the device with the following script, and then load the `nvidia` module; the device was then available on the host: for dev in "0000:01:00.0" "0000:01:00.1"; do if [ -e /sys/bus/pci/devices/${dev}/driver ]; then echo "${dev}" > /sys/bus/pci/devices/${dev}/driver/unbind fi done

qnaal 10y ago

wintermute

pYQAJ6Zm 10y ago

One reason is to mix AMD and NVIDIA GPUs – I experimented with running X on the integrated Radeon device, while running CUDA on a Linux guest with GPU-passthrough. Trying to have CUDA on the host system led to library conflicts.