diff options
| author | Tommi Rantala <tommi.t.rantala@nokia.com> | 2020-03-05 11:37:13 +0300 |
|---|---|---|
| committer | Arnaldo Carvalho de Melo <acme@redhat.com> | 2020-03-06 14:30:47 +0300 |
| commit | f649bd9dd5d5004543bbc3c50b829577b49f5d75 (patch) | |
| tree | 27e6419144bbb9e2768c2a3d4084695084221768 /tools/perf | |
| parent | 29b4f5f188571c112713c35cc87eefb46efee612 (diff) | |
| download | linux-f649bd9dd5d5004543bbc3c50b829577b49f5d75.tar.xz | |
perf bench futex-wake: Restore thread count default to online CPU count
Since commit 3b2323c2c1c4 ("perf bench futex: Use cpumaps") the default
number of threads the benchmark uses got changed from number of online
CPUs to zero:
$ perf bench futex wake
# Running 'futex/wake' benchmark:
Run summary [PID 15930]: blocking on 0 threads (at [private] futex 0x558b8ee4bfac), waking up 1 at a time.
[Run 1]: Wokeup 0 of 0 threads in 0.0000 ms
[...]
[Run 10]: Wokeup 0 of 0 threads in 0.0000 ms
Wokeup 0 of 0 threads in 0.0004 ms (+-40.82%)
Restore the old behavior by grabbing the number of online CPUs via
cpu->nr:
$ perf bench futex wake
# Running 'futex/wake' benchmark:
Run summary [PID 18356]: blocking on 8 threads (at [private] futex 0xb3e62c), waking up 1 at a time.
[Run 1]: Wokeup 8 of 8 threads in 0.0260 ms
[...]
[Run 10]: Wokeup 8 of 8 threads in 0.0270 ms
Wokeup 8 of 8 threads in 0.0419 ms (+-24.35%)
Fixes: 3b2323c2c1c4 ("perf bench futex: Use cpumaps")
Signed-off-by: Tommi Rantala <tommi.t.rantala@nokia.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Darren Hart <dvhart@infradead.org>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lore.kernel.org/lkml/20200305083714.9381-3-tommi.t.rantala@nokia.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools/perf')
| -rw-r--r-- | tools/perf/bench/futex-wake.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/tools/perf/bench/futex-wake.c b/tools/perf/bench/futex-wake.c index df810096abfe..58906e9499bb 100644 --- a/tools/perf/bench/futex-wake.c +++ b/tools/perf/bench/futex-wake.c @@ -43,7 +43,7 @@ static bool done = false, silent = false, fshared = false; static pthread_mutex_t thread_lock; static pthread_cond_t thread_parent, thread_worker; static struct stats waketime_stats, wakeup_stats; -static unsigned int ncpus, threads_starting, nthreads = 0; +static unsigned int threads_starting, nthreads = 0; static int futex_flag = 0; static const struct option options[] = { @@ -141,7 +141,7 @@ int bench_futex_wake(int argc, const char **argv) sigaction(SIGINT, &act, NULL); if (!nthreads) - nthreads = ncpus; + nthreads = cpu->nr; worker = calloc(nthreads, sizeof(*worker)); if (!worker) |