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Thu, 05 Mar 2020 06:51:51 -0800 (PST) From: Arnaldo Carvalho de Melo X-Google-Original-From: Arnaldo Carvalho de Melo Received: by quaco.ghostprotocols.net (Postfix, from userid 1000) id 83DA5403AD; Thu, 5 Mar 2020 11:51:49 -0300 (-03) Date: Thu, 5 Mar 2020 11:51:49 -0300 To: Tommi Rantala Cc: Peter Zijlstra , Ingo Molnar , Thomas Gleixner , Darren Hart , Mark Rutland , Alexander Shishkin , Jiri Olsa , Namhyung Kim , Davidlohr Bueso , linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/3] perf bench futex-wake: Restore thread count default to online CPU count Message-ID: <20200305145149.GB7895@kernel.org> References: <20200305083714.9381-1-tommi.t.rantala@nokia.com> <20200305083714.9381-3-tommi.t.rantala@nokia.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200305083714.9381-3-tommi.t.rantala@nokia.com> X-Url: http://acmel.wordpress.com Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Em Thu, Mar 05, 2020 at 10:37:13AM +0200, Tommi Rantala escreveu: > 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") Thanks, tested and applied. - Arnaldo > Signed-off-by: Tommi Rantala > --- > tools/perf/bench/futex-wake.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/tools/perf/bench/futex-wake.c b/tools/perf/bench/futex-wake.c > index df810096abfef..58906e9499bb0 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) > -- > 2.21.1 > -- - Arnaldo