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From: Jason Low <jason.low2@hp.com>
To: Preeti U Murthy <preeti@linux.vnet.ibm.com>
Cc: Morten Rasmussen <morten.rasmussen@arm.com>,
	Peter Zijlstra <peterz@infradead.org>,
	"mingo@kernel.org" <mingo@kernel.org>,
	"riel@redhat.com" <riel@redhat.com>,
	"daniel.lezcano@linaro.org" <daniel.lezcano@linaro.org>,
	"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: [PATCH V2] sched: Improve load balancing in the presence of idle CPUs
Date: Tue, 31 Mar 2015 10:30:08 -0700	[thread overview]
Message-ID: <1427823008.2492.19.camel@j-VirtualBox> (raw)
In-Reply-To: <551A61A9.6020009@linux.vnet.ibm.com>

On Tue, 2015-03-31 at 14:28 +0530, Preeti U Murthy wrote:

> Morten,

> I am a bit confused about the problem you are pointing to.

> I am unable to see the issue. What is it that I am missing ?

Hi Preeti,

Here is one of the potential issues that have been described from my
understanding.

In situations where there are just a few tasks to pull (for example,
there's 1 task to move).

Before, if CPU 1 calls run_rebalance_domains(), we'll pull the tasks to
this CPU 1 (which is already awake) and run the task on CPU 1.

Now, we'll pull the task to some idle CPU 2 and wake up CPU 2 in order
for the task to run. Meanwhile, CPU 1 may go idle, instead of running
the task on CPU 1 which was already awake.


  reply	other threads:[~2015-03-31 17:30 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-03-26 13:02 [PATCH V2] sched: Improve load balancing in the presence of idle CPUs Preeti U Murthy
2015-03-26 17:03 ` Jason Low
2015-03-27  2:12 ` Wanpeng Li
2015-03-27  4:33   ` Preeti U Murthy
2015-03-27  4:23     ` Wanpeng Li
2015-03-27  5:01     ` Jason Low
2015-03-27  5:07   ` Jason Low
2015-03-27  5:39     ` Srikar Dronamraju
2015-03-27  7:00       ` Wanpeng Li
2015-03-27  6:43     ` Wanpeng Li
2015-03-27 16:23     ` Preeti U Murthy
2015-03-27 11:43 ` [tip:sched/core] " tip-bot for Preeti U Murthy
2015-03-27 13:03 ` [PATCH V2] " Srikar Dronamraju
2015-03-27 14:38 ` Morten Rasmussen
2015-03-27 16:46   ` Preeti U Murthy
2015-03-27 17:56     ` Morten Rasmussen
2015-03-30  7:26       ` Preeti U Murthy
2015-03-30 11:30         ` Morten Rasmussen
2015-03-30 11:06       ` Peter Zijlstra
2015-03-30 12:03         ` Morten Rasmussen
2015-03-30 12:24           ` Peter Zijlstra
2015-03-30 12:54             ` Peter Zijlstra
2015-03-30 13:29             ` Vincent Guittot
2015-03-30 14:01               ` Peter Zijlstra
2015-03-30 15:27               ` Morten Rasmussen
2015-03-31  8:58           ` Preeti U Murthy
2015-03-31 17:30             ` Jason Low [this message]
2015-04-01  6:28               ` Preeti U Murthy
2015-04-01 13:03                 ` Morten Rasmussen
2015-04-02  0:55                   ` Jason Low
2015-04-02  3:22                   ` Preeti U Murthy
2015-03-30 13:45 ` Vincent Guittot
2015-03-31  8:06   ` Preeti U Murthy

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