Date: Tue, 5 Apr 2016 08:15:52 +0800
From: Yuyang Du <yuyang.du@intel.com>
To: Morten Rasmussen <morten.rasmussen@arm.com>
Cc: Leo Yan <leo.yan@linaro.org>, Steve Muckle <steve.muckle@linaro.org>,
        Peter Zijlstra <peterz@infradead.org>, Ingo Molnar <mingo@redhat.com>,
        Dietmar Eggemann <dietmar.eggemann@arm.com>,
        Vincent Guittot <vincent.guittot@linaro.org>,
        linux-kernel@vger.kernel.org, eas-dev@lists.linaro.org
Subject: Re: [PATCH RFC] sched/fair: let cpu's cfs_rq to reflect task
 migration
Message-ID: <20160405001552.GB8697@intel.com>
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 <56FEF621.3070404@linaro.org>
 <20160402071154.GA7046@leoy-linaro>
 <20160404084821.GA18516@e105550-lin.cambridge.arm.com>
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On Tue, Apr 05, 2016 at 08:51:13AM +0100, Morten Rasmussen wrote:
> On Tue, Apr 05, 2016 at 02:30:03AM +0800, Yuyang Du wrote:
> > On Mon, Apr 04, 2016 at 09:48:23AM +0100, Morten Rasmussen wrote:
> > > On Sat, Apr 02, 2016 at 03:11:54PM +0800, Leo Yan wrote:
> > > > On Fri, Apr 01, 2016 at 03:28:49PM -0700, Steve Muckle wrote:
> > > > > I think I follow - Leo please correct me if I mangle your intentions.
> > > > > It's an issue that Morten and Dietmar had mentioned to me as well.
> > > 
> > > Yes. We have been working on this issue for a while without getting to a
> > > nice solution yet.
> >  
> > So do you want a "flat hirarchy" for util_avg - just do util_avg for
> > rq and task respectively? Seems it is what you want, and it is even easier?
> 
> Pretty much, yes. I can't think of a good reason why we need the
> utilization of groups as long as we have the task utilization and the
> sum of those for the root cfs_rq.
 
Sound good to me too.

> I'm not saying it can't be implemented, just saying that it will make
> utilization tracking for groups redundant and possibly duplicate or hack
> some the existing code to implement the new root utilization sum.

A initial evaluation of the implementation: it looks much easier to do (at
least) than the current. Lets wait for a day or two, if no objection, then
lets do it.