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| author | Davidlohr Bueso <davidlohr@hp.com> | 2013-12-15 08:31:56 +0400 |
|---|---|---|
| committer | Arnaldo Carvalho de Melo <acme@redhat.com> | 2014-03-14 18:20:43 +0400 |
| commit | 27db78307481dbba68c5f3563c6cb694b25521d9 (patch) | |
| tree | c83a241df6bae6c30fec37c6e26dcc7f3a4a9520 /tools/perf/bench/futex.h | |
| parent | a043971141f163f9845324a2f83502d15011485d (diff) | |
| download | linux-27db78307481dbba68c5f3563c6cb694b25521d9.tar.xz | |
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>
Diffstat (limited to 'tools/perf/bench/futex.h')
| -rw-r--r-- | tools/perf/bench/futex.h | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/tools/perf/bench/futex.h b/tools/perf/bench/futex.h index 7d0bda543e3d..6ac45093fac4 100644 --- a/tools/perf/bench/futex.h +++ b/tools/perf/bench/futex.h @@ -45,4 +45,14 @@ futex_wait(u_int32_t *uaddr, u_int32_t val, struct timespec *timeout, int opflag return futex(uaddr, FUTEX_WAIT, val, timeout, NULL, 0, opflags); } +/** + * futex_wake() - wake one or more tasks blocked on uaddr + * @nr_wake: wake up to this many tasks + */ +static inline int +futex_wake(u_int32_t *uaddr, int nr_wake, int opflags) +{ + return futex(uaddr, FUTEX_WAKE, nr_wake, NULL, NULL, 0, opflags); +} + #endif /* _FUTEX_H */ |