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>
diff --git a/tools/perf/Makefile.perf b/tools/perf/Makefile.perf
index 54ae547..6fa5d8b 100644
--- a/tools/perf/Makefile.perf
+++ b/tools/perf/Makefile.perf
@@ -427,6 +427,7 @@
BUILTIN_OBJS += $(OUTPUT)bench/mem-memcpy.o
BUILTIN_OBJS += $(OUTPUT)bench/mem-memset.o
BUILTIN_OBJS += $(OUTPUT)bench/futex-hash.o
+BUILTIN_OBJS += $(OUTPUT)bench/futex-wake.o
BUILTIN_OBJS += $(OUTPUT)builtin-diff.o
BUILTIN_OBJS += $(OUTPUT)builtin-evlist.o