From: Davidlohr Bueso <davidlohr@hp.com>
Date: Sun, 15 Dec 2013 04:31:56 +0000 (-0800)
Subject: perf bench: Add futex-wake microbenchmark
X-Git-Tag: v3.15-rc1~181^2~1^2~14
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=27db78307481dbba68c5f3563c6cb694b25521d9;p=pandora-kernel.git

perf bench: Add futex-wake microbenchmark

Block a bunch of threads on a futex and wake them up, N at a time.

This program is particularly useful to measure the latency of nthread
wakeups in non-error situations:  all waiters are queued and all wake
calls wakeup one or more tasks.

An example run:

  $ perf bench futex wake -t 512 -r 100
  Run summary [PID 27823]: blocking on 512 threads (at futex 0x7e10d4), waking up 1 at a time.

  [Run 1]: Wokeup 512 of 512 threads in 6.0080 ms
  [Run 2]: Wokeup 512 of 512 threads in 5.2280 ms
  [Run 3]: Wokeup 512 of 512 threads in 4.8300 ms
  ...
  [Run 100]: Wokeup 512 of 512 threads in 5.0100 ms
  Wokeup 512 of 512 threads in 5.0109 ms (+-2.25%)

Signed-off-by: Davidlohr Bueso <davidlohr@hp.com>
Acked-by: Darren 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/1387081917-9102-3-git-send-email-davidlohr@hp.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---

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