8 Replies Latest reply on Dec 12, 2014 3:53 AM by dipak

    OpenCL 2.0 CPU support

    tqian

      A quick question / clarification on the status of CPU support for OpenCL 2.0:

       

      I installed the AMD APP SDK 3.0 beta, assuming that it brings OpenCL 2.0 support to CPUs as well. The previous versions support OpenCL 1.2 on both Intel and AMD CPUs. However, in clinfo, both my AMD and Intel machines still show only OpenCL 1.2 support. Is this supposed to be the case? If so, is there a plan to bring OpenCL 2.0 support to CPUs?

       

      Thanks!

        • Re: OpenCL 2.0 CPU support
          nibal

          I assume you use Windows and have both SDKs. In Linux you can only have one. To my knowledge SDK 3.0 supports both CPUs and GPUs. clinfo seems to have a bug and reports erroneously OpenCL 1.2. I haven't tried SDK 3.0, however, and could be mistaken. You can always try removing openCL 1.2 and retry clinfo. You can always install it back ;-)

          1 of 1 people found this helpful
            • Re: OpenCL 2.0 CPU support
              tqian

              Thanks! I am on Linux and have only the 3.0 beta. The official AMD guy below said CPUs are not supported yet - bummer! I am a fan of using OpenCL on CPUs - almost linear increase in speed (with respect to the number of cores) without all the complications!

               

              We'll just have to wait. ;-)

            • Re: OpenCL 2.0 CPU support
              dipak

              Currently, AMD CPUs do not support OpenCL 2.0, so they are not listed as OpenCL 2.0 supported devices in the clinfo output. For the same reason, any sample with OpenCL2.0 features will not work on the CPUs. Please check the APP SDK FAQ document for more details.

               

              Regards,

                • Re: OpenCL 2.0 CPU support
                  tqian

                  Thanks for the answer - is there a plan to introduce CPU support?

                  • Re: OpenCL 2.0 CPU support
                    nibal

                    Dipak:

                    "Currently, AMD CPUs do not support OpenCL 2.0, so they are not listed as OpenCL 2.0 supported devices in the clinfo output. For the same reason, any sample with OpenCL2.0 features will not work on the CPUs."

                    "AFAIK, it is definitely part of our future plan but can not comment about timeline."

                     

                    1st statement indicates hardware problem with AMD CPUs. The 2nd one indicates a future software driver upgrade solution. Does this mean that it will be a software workaround for hardware limitations? Any performance issues?

                      • Re: OpenCL 2.0 CPU support
                        tqian

                        I may be naive, but the chance of actual hardware problems seems low - Intel already has an experimental CPU-only OpenCL 2.0 Driver, which works on as early as Ivy Bridges (in Windows, I have yet to get it work in Linux). So, AMD only has to match that, which I imagine would take time, but doesn't sound that difficult.

                        • Re: OpenCL 2.0 CPU support
                          dipak

                          This is not exactly a hardware limitation. What I meant to say that currently there is no OpenCL 2.0 support on AMD CPUs. Or another way you can say  that currently AMD OpenCL runtime/driver does not support OpenCL 2.0 on AMD CPUs. I guess once the CPU support is available it should work without any performance limitation.