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CPU usage becomes always 100 percent irrespective of number of cores specified RRS feed

  • Question

  • Hello, My name is Masanari HATTORI, trying to run a program with MS-MPI. My computer consists of 4 physical/locical cores. What I expected was that computing with "mpiexec -np 4 foo.exe" leads to 100% CPU usage with 4 processes, "mpiexec -np 2 foo.exe" leads to 50% CPU usage with 2 processes, and "mpiexec -np 1 foo.exe" leads to 25% CPU usage with 1 processes. (which was true in some linux cluster with mpich2.) However, what I actually saw was that in all cases the CPU usage was 100%, although the number of processes running was 4, 2, or 1 as expected. What should I do to resolve this problem? Thank you for your help in advance.

    Sincerely yours,

    Masanari HATTORI

    Saturday, February 24, 2018 10:15 AM

Answers

  • You can specify using affinity on the command line.

    Try:

    mpiexec -a -n 4 foo.exe

    mpiexec -a -n 2 foo.exe

    mpiexec -a -n 1 foo.exe

    And check CPU usage for each one. Thanks.

    Monday, February 26, 2018 5:36 PM

All replies

  • You can specify using affinity on the command line.

    Try:

    mpiexec -a -n 4 foo.exe

    mpiexec -a -n 2 foo.exe

    mpiexec -a -n 1 foo.exe

    And check CPU usage for each one. Thanks.

    Monday, February 26, 2018 5:36 PM
  • Dear Jeff HPC,

    Thank you for your information. I appreciate your help.

    Sincerely yours,

    Masanari HATTORI

    Tuesday, February 27, 2018 3:20 AM