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authorDavidlohr Bueso <davidlohr@hp.com>2013-12-15 05:31:56 +0100
committerArnaldo Carvalho de Melo <acme@redhat.com>2014-03-14 15:20:43 +0100
commit27db78307481dbba68c5f3563c6cb694b25521d9 (patch)
treec83a241df6bae6c30fec37c6e26dcc7f3a4a9520 /tools/perf/bench/futex.h
parentperf bench: Add futex-hash microbenchmark (diff)
downloadlinux-27db78307481dbba68c5f3563c6cb694b25521d9.tar.xz
linux-27db78307481dbba68c5f3563c6cb694b25521d9.zip
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.h10
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 */