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Date: Thu, 10 Sep 2015 12:07:27 +0200
From: Peter Zijlstra <peterz@infradead.org>
To: Yuyang Du <yuyang.du@intel.com>
Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>,
        Vincent Guittot <vincent.guittot@linaro.org>,
        Steve Muckle <steve.muckle@linaro.org>,
        Morten Rasmussen <Morten.Rasmussen@arm.com>,
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Subject: Re: [PATCH 5/6] sched/fair: Get rid of scaling utilization by
 capacity_orig
Message-ID: <20150910100727.GU3644@twins.programming.kicks-ass.net>
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On Thu, Sep 10, 2015 at 04:15:20AM +0800, Yuyang Du wrote:
> On Tue, Sep 08, 2015 at 01:50:38PM +0100, Dietmar Eggemann wrote:
> > > It's both a unit and a SCALE/SHIFT problem, SCHED_LOAD_SHIFT and
> > > SCHED_CAPACITY_SHIFT are defined separately so we must be sure to
> > > scale the value in the right range. In the case of cpu_usage which
> > > returns sa->util_avg , it's the capacity range not the load range.
> > 
> > Still don't understand why it's a unit problem. IMHO LOAD/UTIL and
> > CAPACITY have no unit.
> 
> To be more accurate, probably, LOAD can be thought of as having unit,
> but UTIL has no unit.

But I'm thinking that is wrong; it should have one, esp. if we go scale
the thing. Giving it the same fixed point unit as load simplifies the
code.