• Davidlohr Bueso's avatar
    perf bench: Add futex-requeue microbenchmark · 0fb298cf
    Davidlohr Bueso authored
    Block a bunch of threads on a futex and requeue them on another, N at a
    time.
    
    This program is particularly useful to measure the latency of nthread
    requeues without waking up any tasks -- thus mimicking a regular
    futex_wait.
    
    An example run:
    
      $ perf bench futex requeue -r 100 -t 64
      Run summary [PID 151011]: Requeuing 64 threads (from 0x7d15c4 to 0x7d15c8), 1 at a time.
    
      [Run 1]: Requeued 64 of 64 threads in 0.0400 ms
      [Run 2]: Requeued 64 of 64 threads in 0.0390 ms
      [Run 3]: Requeued 64 of 64 threads in 0.0400 ms
      ...
      [Run 100]: Requeued 64 of 64 threads in 0.0390 ms
      Requeued 64 of 64 threads in 0.0399 ms (+-0.37%)
    Signed-off-by: default avatarDavidlohr Bueso <davidlohr@hp.com>
    Acked-by: default avatarDarren Hart <dvhart@linux.intel.com>
    Cc: Aswin Chandramouleeswaran <aswin@hp.com>
    Cc: Darren Hart <dvhart@linux.intel.com>
    Cc: Ingo Molnar <mingo@redhat.com>
    Cc: Jason Low <jason.low2@hp.com>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Cc: Scott J Norton <scott.norton@hp.com>
    Cc: Thomas Gleixner <tglx@linutronix.de>
    Cc: Waiman Long <Waiman.Long@hp.com>
    Link: http://lkml.kernel.org/r/1387081917-9102-4-git-send-email-davidlohr@hp.comSigned-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
    0fb298cf
futex-requeue.c 5.67 KB