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From: Victor Jimenez <victor.javier@bsc.es>
To: linux-perf-users@vger.kernel.org
Subject: Problem when profiling a process' running/sleeping/waiting time
Date: Wed, 09 Jan 2013 11:56:32 +0100	[thread overview]
Message-ID: <50ED4CE0.7050201@bsc.es> (raw)

I am trying to profile a process in terms of running, sleeping and 
waiting time. I am using kernel 3.6.6 running on an IBM POWER7 machine. 
Initially, I decided to use a toy example where I would expect that the 
process remains in running state most of the time. This is the code for 
such a simple example:

int main() {
     for (int i = 0; i < 1000000; i++)
         for (int j = 0; j < 1000; j++);
}

I am using the following command line for reading kernel stats:

perf stat -e 
"sched:sched_stat_runtime,sched:sched_stat_sleep,sched:sched_stat_wait, \
     sched:sched_stat_iowait,sched:sched_stat_blocked" ./test

And these are the results that I obtain:

  Performance counter stats for './test':

     12,077,957,756 sched:sched_stat_runtime
    169,892,740,990 sched:sched_stat_sleep
          5,816,784 sched:sched_stat_wait
                  0 sched:sched_stat_iowait
                  0 sched:sched_stat_blocked

      12.084706279  seconds time elapsed

I cannot really understand why the counter for sched_stat_sleep is so 
high (even higher than sched_stat_runtime), especially for such a 
CPU-bound workload.

Am I missing anything, or there could be a problem with sched_stat_sleep 
counter?

Thank you,
Victor

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             reply	other threads:[~2013-01-09 11:06 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-01-09 10:56 Victor Jimenez [this message]
2013-06-17  7:20 ` Problem when profiling a process' running/sleeping/waiting time Michael Ellerman

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