From: Davidlohr Bueso <dave@stgolabs.net>
To: Arnaldo Carvalho de Melo <arnaldo.melo@gmail.com>
Cc: Tommi Rantala <tommi.t.rantala@nokia.com>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
Darren Hart <dvhart@infradead.org>,
Mark Rutland <mark.rutland@arm.com>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Jiri Olsa <jolsa@redhat.com>, Namhyung Kim <namhyung@kernel.org>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/3] perf bench futex-wake: Restore thread count default to online CPU count
Date: Thu, 5 Mar 2020 07:34:34 -0800 [thread overview]
Message-ID: <20200305153434.5r2jqsfxyrusrgwc@linux-p48b> (raw)
In-Reply-To: <20200305145149.GB7895@kernel.org>
On Thu, 05 Mar 2020, Arnaldo Carvalho de Melo wrote:
>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.
Thanks!
next prev parent reply other threads:[~2020-03-05 15:46 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20200305083714.9381-1-tommi.t.rantala@nokia.com>
2020-03-05 8:37 ` [PATCH 1/3] perf top: Fix stdio interface input handling with glibc 2.28+ Tommi Rantala
2020-03-05 14:49 ` Arnaldo Carvalho de Melo
2020-03-06 7:47 ` Rantala, Tommi T. (Nokia - FI/Espoo)
2020-03-07 7:36 ` [tip: perf/urgent] " tip-bot2 for Tommi Rantala
2020-03-05 8:37 ` [PATCH 2/3] perf bench futex-wake: Restore thread count default to online CPU count Tommi Rantala
2020-03-05 14:51 ` Arnaldo Carvalho de Melo
2020-03-05 15:34 ` Davidlohr Bueso [this message]
2020-03-05 18:14 ` Arnaldo Melo
2020-03-07 7:36 ` [tip: perf/urgent] " tip-bot2 for Tommi Rantala
2020-03-05 8:37 ` [PATCH 3/3] perf bench: Clear struct sigaction before sigaction() syscall Tommi Rantala
2020-03-05 14:53 ` Arnaldo Carvalho de Melo
2020-03-07 7:36 ` [tip: perf/urgent] " tip-bot2 for Tommi Rantala
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