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I am running Ubuntu 22.04 on a laptop with Intel 12th Gen CPU, with 8 p-cores and 8 e-cores. The CPU supports 24 total threads, 2 for each p-core and 1 for each e-core. Ubuntu identifies the model of the CPU correctly but only recognizes 12 cores and 24 threads. I am running parallel jobs with OpenMPI, which also complains if I try to use more than 12 cores. I also noticed some processes run much faster than others, likely due to the p-core vs e-core speed difference.

I am wondering if there are any suggestions to have Ubuntu and OpenMPI recognize all cores and hopefully distinguish p-cores vs e-cores? Thanks.

Update: I tried Ubuntu 22.04 with a liveusb again and it reported the number of cores and threads correctly. So the issue is most likely from the Windows Subsystem for Linux.

ZL-Arctic
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  • What Kernel version are you running on this system? Please edit your question and add some more details about the system. This might be a bug in the Kernel if it is fully updated and still cannot see all available cores in the OS. If that is the case, I would recommend to file a bug on launchpad so that it can be fixed and tracked. – Terrance Jan 26 '23 at 03:16
  • I am using Ubuntu 22.04 from Windows Subsystem (WSL2). The kernel version is 5.15.79.1-microsoft-standard-WSL2. The Windows 11 recognized all the cores and total thread number correctly. It is interesting that Ubuntu get the thread number right. The core number is wrong but the it is half of the thread number, which is true for the previous generation Intel processors. – ZL-Arctic Jan 26 '23 at 05:15

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