From: Jason Low <jason.low2@hp.com>
To: Morten Rasmussen <morten.rasmussen@arm.com>
Cc: Preeti U Murthy <preeti@linux.vnet.ibm.com>,
"peterz@infradead.org" <peterz@infradead.org>,
"mingo@kernel.org" <mingo@kernel.org>,
Daniel Lezcano <daniel.lezcano@linaro.org>,
"riel@redhat.com" <riel@redhat.com>,
"vincent.guittot@linaro.org" <vincent.guittot@linaro.org>,
"srikar@linux.vnet.ibm.com" <srikar@linux.vnet.ibm.com>,
"pjt@google.com" <pjt@google.com>,
"benh@kernel.crashing.org" <benh@kernel.crashing.org>,
"efault@gmx.de" <efault@gmx.de>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"iamjoonsoo.kim@lge.com" <iamjoonsoo.kim@lge.com>,
"svaidy@linux.vnet.ibm.com" <svaidy@linux.vnet.ibm.com>,
"tim.c.chen@linux.intel.com" <tim.c.chen@linux.intel.com>,
jason.low2@hp.com
Subject: Re: sched: Improve load balancing in the presence of idle CPUs
Date: Thu, 02 Apr 2015 10:22:07 -0700 [thread overview]
Message-ID: <1427995327.2556.54.camel@j-VirtualBox> (raw)
In-Reply-To: <20150402091704.GZ18994@e105550-lin.cambridge.arm.com>
On Thu, 2015-04-02 at 10:17 +0100, Morten Rasmussen wrote:
> On Thu, Apr 02, 2015 at 06:59:07AM +0100, Jason Low wrote:
> > Also, below is an example patch.
> >
> > (Without the conversion to idle_cpu(), the check for rq->idle_balance
> > would not be accurate anymore)
> I think this should reduce the latency Preeti is seeing and avoid
> unnecessary wake-ups, however, it may not be quite as aggressive in
> spreading tasks quickly. It will stop the chain-of-kicks as soon as the
> balancer cpu has pulled only one task. The source cpu may still be
> having two tasks and other cpus may still have more than two tasks
> running.
Yeah, good point. I'll wait and see if Preeti finds this to improve
scheduling behavior. If this only helps a little though, we can also try
to make it more aggressive in spreading tasks.
> Depending on how bad it is, we could consider kicking another cpu if the
> imbalance is still significant after the balancer cpu has pulled a task.
next prev parent reply other threads:[~2015-04-02 17:22 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 [this message]
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
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