Re: [PATCH]time: Optimize nohz idle enter
From: Thomas Gleixner
Date: Tue Jul 19 2016 - 06:48:18 EST
On Tue, 19 Jul 2016, Gaurav Jindal (Gaurav Jindal) wrote:
> On Tue, Jul 19, 2016 at 10:47:37AM +0200, Thomas Gleixner wrote:
> > 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.
> Actually Sanjeev and me worked together, but since only one send the mail so I
> included his name as SOB.
That does not make it more correct. See Documentation/SubmittingPatches. I
fixed it up.