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From: Jason Low <jason.low2@hp.com>
To: Preeti U Murthy <preeti@linux.vnet.ibm.com>
Cc: peterz@infradead.org, mingo@kernel.org,
	Daniel Lezcano <daniel.lezcano@linaro.org>,
	riel@redhat.com, vincent.guittot@linaro.org,
	srikar@linux.vnet.ibm.com, pjt@google.com,
	benh@kernel.crashing.org, efault@gmx.de,
	linux-kernel@vger.kernel.org, iamjoonsoo.kim@lge.com,
	svaidy@linux.vnet.ibm.com, tim.c.chen@linux.intel.com,
	morten.rasmussen@arm.com, jason.low2@hp.com
Subject: Re: sched: Improve load balancing in the presence of idle CPUs
Date: Wed, 01 Apr 2015 19:11:52 -0700	[thread overview]
Message-ID: <1427940712.2556.14.camel@j-VirtualBox> (raw)
In-Reply-To: <551A5CCE.70008@linux.vnet.ibm.com>

On Tue, 2015-03-31 at 14:07 +0530, Preeti U Murthy wrote:
> On 03/31/2015 12:25 AM, Jason Low wrote:

> > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> > index fdae26e..ba8ec1a 100644
> > --- a/kernel/sched/fair.c
> > +++ b/kernel/sched/fair.c
> > @@ -7644,7 +7644,7 @@ static void nohz_idle_balance(struct rq *this_rq, enum cpu_idle_type idle)
> >  		 * balancing owner will pick it up.
> >  		 */
> >  		if (need_resched())
> > -			break;
> > +			goto end;
> 
> Why is this hunk needed?

In terms of the change in the need_resched() case, if the current CPU
doesn't complete iterating all of the CPUs, then this will make it not
update nohz.next_balance. This is so we can continue the balancing with
the next balancing owner without too much delay.


      parent reply	other threads:[~2015-04-02  2:13 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-03-30 18:55 sched: Improve load balancing in the presence of idle CPUs Jason Low
2015-03-31  8:37 ` Preeti U Murthy
2015-03-31 18:54   ` Jason Low
2015-04-01  6:49     ` Preeti U Murthy
2015-04-01 17:04       ` Morten Rasmussen
2015-04-02  3:30         ` Jason Low
2015-04-02  8:49           ` Morten Rasmussen
2015-04-02  5:59         ` Jason Low
2015-04-02  8:42           ` Preeti U Murthy
2015-04-02  9:17           ` Morten Rasmussen
2015-04-02 17:22             ` Jason Low
2015-04-03 22:35           ` Tim Chen
2015-04-07 17:42             ` Jason Low
2015-04-07 19:39               ` Tim Chen
2015-04-07 20:24                 ` Jason Low
2015-04-04  9:59           ` Preeti U Murthy
2015-04-07 23:28             ` Jason Low
2015-04-08  0:07               ` Jason Low
2015-04-08 11:12                 ` Srikar Dronamraju
2015-04-08 21:22                   ` Jason Low
2015-04-10  8:37                     ` Srikar Dronamraju
2015-04-13 18:55                       ` Jason Low
2015-04-13 20:54                       ` Jason Low
2015-04-09  2:39                   ` Jason Low
2015-04-09  7:02                     ` Srikar Dronamraju
2015-04-09 22:49                       ` Jason Low
2015-04-13  6:16                 ` Preeti U Murthy
2015-04-13 22:49                   ` Jason Low
2015-04-14  2:59                     ` Jason Low
2015-04-02  2:11   ` Jason Low [this message]

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