From: Davidlohr Bueso <davidlohr@hp.com>
Date: Sun, 15 Dec 2013 04:31:57 +0000 (-0800)
Subject: perf bench: Add futex-requeue microbenchmark
X-Git-Tag: v3.15-rc1~181^2~1^2~13
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=0fb298cf95c0d8119557b7d4657724a146e0622e;p=pandora-kernel.git

perf bench: Add futex-requeue microbenchmark

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: 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/1387081917-9102-4-git-send-email-davidlohr@hp.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---

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