Multi Tesla and OpenGL Rendering on Headless Linux node.


We are trying to setup a server with Multiple Tesla M2050 to run with OpenGL. The current setup is as follows : Ubuntu 12.04 with NVidia Drivers. We have setup the xorg.conf with separate devices identified by BUS ID. Now we have tied an X server each with display which in turn is tied to each device and our code is attached to each of these X servers. But somehow only one X session seems to work out alright. The other one produces garbled output and while watching it from nvidia-smi, we notice that when the garbled output is being produced the GPU’s are not at all used. Could someone verify that our setup seems reasonable. The other thing we noticed was that, it was only the first X server that was started is the one that has the issue. Any help is appreciated.


Only one X server can be active at a time, so when you start the second X server, the system is VT-switching away from the first one. Your best bet is to configure a single X server with each GPU as a separate X screen (e.g. “sudo nvidia-xconfig --enable-all-gpus”) and then use DISPLAY=:0.0, DISPLAY=:0.1, etc. to address each GPU. You might be able to get it to work with separate X servers by disabling the ProbeAllGpus option on all of them and starting your X servers with -sharevts -novtswitch, but please be aware that that is not an officially supported configuration.