Public bug reported: When running OpenCL applications on Elkhart Lake iGPU (x6425RE), we observe performance drop about 35% when run with Intel VTune GPU Compute/Media Hotspots mode.
For example, running a sgemm sample from CLBlast (github.com/CNugteren/CLBlast/samples/sgemm.cpp) results in following (modified to run 10 iterations): $ ./clblast_sample_sgemm Completed SGEMM in 1107.954 ms with status 0 Completed SGEMM in 0.727 ms with status 0 Completed SGEMM in 0.684 ms with status 0 Completed SGEMM in 0.900 ms with status 0 Completed SGEMM in 0.692 ms with status 0 Completed SGEMM in 0.668 ms with status 0 Completed SGEMM in 0.678 ms with status 0 Completed SGEMM in 0.668 ms with status 0 Completed SGEMM in 0.674 ms with status 0 Completed SGEMM in 0.678 ms with status 0 However if we do the same run with VTune the performance drops. $ vtune -collect gpu-hotspots -- ./clblast_sample_sgemm ... Completed SGEMM in 1206.028 ms with status 0 Completed SGEMM in 1.254 ms with status 0 Completed SGEMM in 1.130 ms with status 0 Completed SGEMM in 1.070 ms with status 0 Completed SGEMM in 1.035 ms with status 0 Completed SGEMM in 1.149 ms with status 0 Completed SGEMM in 1.122 ms with status 0 Completed SGEMM in 1.029 ms with status 0 Completed SGEMM in 0.984 ms with status 0 Completed SGEMM in 1.076 ms with status 0 We do not observe similar performance drop on Apollo Lake x7-E3950 with the same software setup. This may be an issue on VTune side but difficult to tell. Environment: - OS: Ubuntu for Intel IOT platform 20.04.4 (kernel: 5.13.0-1010-intel) - CPU: Atom x6425RE - VTune version: 2022.1.0 - OpenCL environment: Setup based on drivers from https://dgpu-docs.intel.com/releases/releases-20211130.html ** Affects: ubuntu Importance: Undecided Status: New -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1968955 Title: OpenCL performance degrades when run with Intel VTune To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+bug/1968955/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
