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Thread: kworkers are going crazy and spoil OpenMp

  1. #1
    Join Date
    Mar 2012
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    kworkers are going crazy and spoil OpenMp

    How could I stop kworkers going crazy ?

    term-1 top,
    term-2 cbm1 <- APP using OpenMP to calculate PI,
    term-3 exec command for debugging

    ++ For about 5 minuts since APP started, kworkers were sane,
    ++ and APP used cpu 198% (dual core).
    ++ Screenshot :
    http://a-wada.s30.xrea.com/xxknl/Scr...2-13-16-08.png

    ++ but, then kworkers woke up and ate cpu 80%+- incessantly
    ++ and APP's went down to 100%+-.
    http://a-wada.s30.xrea.com/xxknl/Scr...2-13-17-41.png
    http://a-wada.s30.xrea.com/xxknl/Scr...2-13-19-05.png
    http://a-wada.s30.xrea.com/xxknl/Scr...2-13-35-57.png

    ++ referring to "7. Debugging" in "/usr/src/linux-source-3.0.0/Documentation/workqueue.txt"

    Code:
    a-wada:~/pai$ sudo su -c 'echo workqueue:workqueue_queue_work > /sys/kernel/debug/tracing/set_event'
    [sudo] password for a-wada:
    a-wada:~/pai$ sudo su -c 'cat /sys/kernel/debug/tracing/trace_pipe > out.txt'
    ^C
    a-wada:~/pai$ ll out*
    -rw-r--r-- 1 root root 23032133 2012-02-22 13:30 out.txt
    a-wada:~/pai$ sudo su -c 'cat /proc/THE_OFFENDING_KWORKER/stack > out2.txt'
    cat: /proc/THE_OFFENDING_KWORKER/stack: No such file or directory
    a-wada:~/pai$ ll out*
    -rw-r--r-- 1 root root 23032133 2012-02-22 13:30 out.txt
    -rw-r--r-- 1 root root 0 2012-02-22 13:33 out2.txt
    http://a-wada.s30.xrea.com/xxknl/out.txt <- output of above commands


    http://a-wada.s30.xrea.com/pailnx64/paicbm.c <- source-code of "cbm1" & log when executed normally.

    Please HELP. Thanks in Advance!
    Last edited by awada; March 7th, 2012 at 07:16 AM. Reason: to be read easily

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