Re: [PATCH]time: Optimize nohz idle enter

From: Thomas Gleixner
Date: Tue Jul 19 2016 - 04:49:58 EST


On Thu, 14 Jul 2016, Gaurav Jindal (Gaurav Jindal) wrote:
>
> tick_nohz_start_idle is called before checking the condition if the idle tick
> can be stopped. In case when can_stop_idle_tick returns 0, the function called
> is of no use thus a extra call doing nothing.
>
> Shifting calling of function tick_nohz_start_idle inside the if condition makes
> sure that corresponding operations are done only if idle tick can be actually
> stopped. Observance for 1 minute on arm64 architecture shows that shifting code
> can prevent 1.5% of extra calls thus optimizing the idle call sequence.

Nice.

> Signed-off-by: gaurav jindal<gaurav.jindal@xxxxxxxxxxxxxx>
> Signed-off-by: sanjeev yadav<sanjeev.yadav@xxxxxxxxxxxxxx>

This SOB chain is wrong. Sanjeev did not send the patch and is not the
author. Please clarify.

Thanks,

tglx