From: Mike Galbraith <efault@gmx.de>
To: Peter Zijlstra <peterz@infradead.org>
Cc: "Nikunj A. Dadhania" <nikunj@linux.vnet.ibm.com>,
mingo@elte.hu, linux-kernel@vger.kernel.org,
Suresh Siddha <suresh.b.siddha@intel.com>
Subject: Re: [PATCH] sched: remove redundant check in select_task_rq_fair
Date: Tue, 07 Jun 2011 12:20:43 +0200 [thread overview]
Message-ID: <1307442043.3625.6.camel@marge.simson.net> (raw)
In-Reply-To: <1307441361.2322.239.camel@twins>
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@infradead.org> 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
prev parent reply other threads:[~2011-06-07 10:20 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-06-07 9:48 Nikunj A. Dadhania
2011-06-07 9:53 ` Peter Zijlstra
2011-06-07 10:04 ` Nikunj A. Dadhania
2011-06-07 10:09 ` Peter Zijlstra
2011-06-07 10:20 ` Mike Galbraith [this message]
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