linux-kernel - Re: [RFC v3 0/5] Add capacity capping support to the CPU controller

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Message-ID: <20170412122215.GF3093@worktop>
Date:   Wed, 12 Apr 2017 14:22:15 +0200
From:   Peter Zijlstra <peterz@...radead.org>
To:     Patrick Bellasi <patrick.bellasi@....com>
Cc:     Tejun Heo <tj@...nel.org>, linux-kernel@...r.kernel.org,
        linux-pm@...r.kernel.org, Ingo Molnar <mingo@...hat.com>,
        "Rafael J . Wysocki" <rafael.j.wysocki@...el.com>,
        Paul Turner <pjt@...gle.com>,
        Vincent Guittot <vincent.guittot@...aro.org>,
        John Stultz <john.stultz@...aro.org>,
        Todd Kjos <tkjos@...roid.com>,
        Tim Murray <timmurray@...gle.com>,
        Andres Oportus <andresoportus@...gle.com>,
        Joel Fernandes <joelaf@...gle.com>,
        Juri Lelli <juri.lelli@....com>,
        Chris Redpath <chris.redpath@....com>,
        Morten Rasmussen <morten.rasmussen@....com>,
        Dietmar Eggemann <dietmar.eggemann@....com>
Subject: Re: [RFC v3 0/5] Add capacity capping support to the CPU controller

On Tue, Apr 11, 2017 at 06:58:33PM +0100, Patrick Bellasi wrote:
> Sorry, I don't get instead what are the "confusing nesting properties"
> you are referring to?

If a parent group sets min=.2 and max=.8, what are the constraints on
its child groups for setting their resp min and max?

I can't immediately gives rules that would make sense.

For instance, allowing a child to lower min would violate the parent
constraint, while allowing a child to increase min would grant the child
more resources than the parent.

Neither seem like a good thing.