From 0fb298cf95c0d8119557b7d4657724a146e0622e Mon Sep 17 00:00:00 2001 From: Davidlohr Bueso Date: Sat, 14 Dec 2013 20:31:57 -0800 Subject: 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 Acked-by: Darren Hart Cc: Aswin Chandramouleeswaran Cc: Darren Hart Cc: Ingo Molnar Cc: Jason Low Cc: Peter Zijlstra Cc: Scott J Norton Cc: Thomas Gleixner Cc: Waiman Long Link: http://lkml.kernel.org/r/1387081917-9102-4-git-send-email-davidlohr@hp.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/bench/futex.h | 13 +++++++++++++ 1 file changed, 13 insertions(+) (limited to 'tools/perf/bench/futex.h') diff --git a/tools/perf/bench/futex.h b/tools/perf/bench/futex.h index 6ac4509..71f2844 100644 --- a/tools/perf/bench/futex.h +++ b/tools/perf/bench/futex.h @@ -55,4 +55,17 @@ futex_wake(u_int32_t *uaddr, int nr_wake, int opflags) return futex(uaddr, FUTEX_WAKE, nr_wake, NULL, NULL, 0, opflags); } +/** +* futex_cmp_requeue() - requeue tasks from uaddr to uaddr2 +* @nr_wake: wake up to this many tasks +* @nr_requeue: requeue up to this many tasks +*/ +static inline int +futex_cmp_requeue(u_int32_t *uaddr, u_int32_t val, u_int32_t *uaddr2, int nr_wake, + int nr_requeue, int opflags) +{ + return futex(uaddr, FUTEX_CMP_REQUEUE, nr_wake, nr_requeue, uaddr2, + val, opflags); +} + #endif /* _FUTEX_H */ -- cgit v1.1