Re: [PATCH 2/3] posix_timers: Defer per process timer stop aftertimers processing

From: Olivier Langlois
Date: Tue Apr 30 2013 - 13:52:07 EST



>
> > Maybe the condition around the posix_cpu_timer_schedule() block inside
> > cpu_timer_fire() could even be a good candidate for 'unlikely'
> > qualifier.
>
> Well, cpu_timer_fire() is probably not a fast path. So helping branch
> prediction there probably won't have much measurable effect in practice.
>
Frederic, I'm totally sure that you are right on the measurable effect.
When I did propose the 'unlikely' qualifier, please note, that I also
had a documentary purpose in mind.

Would you have searched the 'likely' path that does
posix_cpu_timer_schedule() when you did modify the code if the
'unlikely' tag would have been present?

Greetings,
Olivier



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