Re: [PATCH 2/3] perf bench futex-wake: Restore thread count default to online CPU count

From: Arnaldo Melo
Date: Thu Mar 05 2020 - 13:15:39 EST




On March 5, 2020 12:34:34 PM GMT-03:00, Davidlohr Bueso <dave@xxxxxxxxxxxx> wrote:
>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!

Taking that as an Acked-by, ok?

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