9 Replies Latest reply on Aug 26, 2010 4:50 AM by nou

    Initializing multiple GPU's on Linux

    sectroyer

      How can I initialize multiple GPU's in order to use them with OpenCL on Linux?

      Do I need to run multiple X11 instances?

      Is it necessary to have multiple displays connected or is one (main/default) enouth?

        • Initializing multiple GPU's on Linux
          davibu

           

          Originally posted by: sectroyer How can I initialize multiple GPU's in order to use them with OpenCL on Linux?

           

          Do I need to run multiple X11 instances?

           

          Is it necessary to have multiple displays connected or is one (main/default) enouth?

           

           

          Just run the following command and restart the Xserver:

           

          sudo aticonfig --adapter=all  --initial -f

           

          However, beaware, you have to install Catakyst 10.7 and OpenCL SDK 2.1.

           

          SDK 2.2 requires Catalyst 10.7b but the support for multi-gpus in 10.7b is totally broken.

           

          You have also to connect a monitor to each card: headless configuration is not supported (however there is some workaround you can find described in other thread in this forum).

           

           

            • Initializing multiple GPU's on Linux
              sectroyer

              I have tried similar solution with two 5970 and it failed Since this card has two outputs do I have to connect 4 displays if I have two 5970 or is it enouth to connnect two displays (one to every card)? BTW about which workaround you are talking? I have tried few and it didn't work

                • Initializing multiple GPU's on Linux
                  davibu

                   

                  Originally posted by: sectroyer I have tried similar solution with two 5970 and it failed Since this card has two outputs do I have to connect 4 displays if I have two 5970 or is it enouth to connnect two displays (one to every card)? BTW about which workaround you are talking? I have tried few and it didn't work

                   

                   

                  First of all, I hope you are aware that 5970 is supported only as a single GPU by ATI OpenCL. You will be able to see only 2 OpenCL GPU devices out of your 4 GPUs.

                  I have a 5870+5850 connected to the same monitor (I'm using just 2 different input connectors of the same monitor). I don't have a 5970 so I don't know if it can be configured by connecting just one monitor.

                  You can find many posts with google about how to make dummy vga connectors to cheat the GPUs.

                   

                • Initializing multiple GPU's on Linux
                  HarryH

                  google "vga dummy connector"

                    • Initializing multiple GPU's on Linux
                      sectroyer

                      I have a system with two 5970 and  all connectors plugged (Catalyst center reports 4 displays connected) if I setup xorg conf using:

                      aticonfig --adapter=all  --initial -f

                      CLInfo reports only one GPU (first core of first 5970)

                      if I setup xorg using:

                      aticonfig --adapter=0  --initial -f

                      CLInfo repots two GPUs (first and second core of first 5970)

                      Since there is a problem with second cores of 5970 I've also tried seting up xorg using:

                      aticonfig --adapter=0,2  --initial -f

                      Nevertheless it doesn't help at all. After running startx I get black screen after few seconds system reboots I've tested it on few machines. Anyone knows how to make it work ?