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Subject: Re: [PATCH V2] sched: Improve load balancing in the presence of
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From: Jason Low <jason.low2@hp.com>
To: Preeti U Murthy <preeti@linux.vnet.ibm.com>
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Date: Tue, 31 Mar 2015 10:30:08 -0700
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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.