Re: [PATCH] sched: remove redundant check in select_task_rq_fair

From: Mike Galbraith
Date: Tue Jun 07 2011 - 06:20:56 EST


On Tue, 2011-06-07 at 12:09 +0200, Peter Zijlstra wrote:
> On Tue, 2011-06-07 at 15:34 +0530, Nikunj A. Dadhania wrote:
> > On Tue, 07 Jun 2011 11:53:34 +0200, Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:
> > > On Tue, 2011-06-07 at 15:18 +0530, Nikunj A. Dadhania wrote:
> > > > When balancing for wakeup affinity, a redundant check can removed.
> > >
> > > Yes, tempting, but no, now you've got an extra call to wake_affine(),
> > > which is more expensive.
>
> > Ah, got that. How about this, it is more readable. Other options would
> > be to add a comment.
>
> > - if (cpu == prev_cpu || wake_affine(affine_sd, p, sync))
> > + if (cpu != prev_cpu && wake_affine(affine_sd, p, sync))
> > prev_cpu = cpu;
>
> I guess that depends on which way your head is wired and how strong your
> boolean algebra is.. Suresh, Mike any preference? I don't much care
> either way.

Me either.

-Mike


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