Subject: Re: [RFC][PATCH 3/8] sched: update the cpu_power sum during
 load-balance
From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: ego@in.ibm.com
Cc: Ingo Molnar <mingo@elte.hu>, linux-kernel@vger.kernel.org,
       Andreas Herrmann <andreas.herrmann3@amd.com>,
       Balbir Singh <balbir@in.ibm.com>
In-Reply-To: <20090902111759.GB3817@in.ibm.com>
References: <20090901083431.748830771@chello.nl>
	 <20090901083825.985050292@chello.nl>  <20090902111759.GB3817@in.ibm.com>
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Date: Wed, 02 Sep 2009 13:25:06 +0200
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On Wed, 2009-09-02 at 16:47 +0530, Gautham R Shenoy wrote:
> > +     if (local_group) {
> >               balance_cpu = group_first_cpu(group);
> > +             if (balance_cpu == this_cpu)
> > +                     update_sched_power(sd);
> > +     }
> 
> I guess the intention of this check is to ensure that the cpu_power for
> the group of sd is updated only by a specific member of the group and
> that would ideally be the first member of the group.
> 
> Thus, this check has more to do with this_cpu being the
> group_first_cpu() than this_cpu being the balance_cpu. Correct ?

Right, so the load-balancer walks the sd tree in the fashion that only
the first cpu of the domain goes up a level. So I made that cpu also
aggregate the new cpu-power.

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