linux-kernel - Re: [PATCH v10 13/16] sched/core: uclamp: Propagate parent clamps

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Message-ID: <20190622150750.GN657710@devbig004.ftw2.facebook.com>
Date:   Sat, 22 Jun 2019 08:07:50 -0700
From:   Tejun Heo <tj@...nel.org>
To:     Patrick Bellasi <patrick.bellasi@....com>
Cc:     linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
        Ingo Molnar <mingo@...hat.com>,
        Peter Zijlstra <peterz@...radead.org>,
        "Rafael J . Wysocki" <rafael.j.wysocki@...el.com>,
        Vincent Guittot <vincent.guittot@...aro.org>,
        Viresh Kumar <viresh.kumar@...aro.org>,
        Paul Turner <pjt@...gle.com>,
        Quentin Perret <quentin.perret@....com>,
        Dietmar Eggemann <dietmar.eggemann@....com>,
        Morten Rasmussen <morten.rasmussen@....com>,
        Juri Lelli <juri.lelli@...hat.com>,
        Todd Kjos <tkjos@...gle.com>,
        Joel Fernandes <joelaf@...gle.com>,
        Steve Muckle <smuckle@...gle.com>,
        Suren Baghdasaryan <surenb@...gle.com>,
        Alessio Balsini <balsini@...roid.com>
Subject: Re: [PATCH v10 13/16] sched/core: uclamp: Propagate parent clamps

Hello,

On Fri, Jun 21, 2019 at 09:42:14AM +0100, Patrick Bellasi wrote:
> Since it can be interesting for userspace, e.g. system management
> software, to know exactly what the currently propagated/enforced
> configuration is, the effective clamp values are exposed to user-space
> by means of a new pair of read-only attributes
> cpu.util.{min,max}.effective.

Can we not add the effective interface file for now?  I don't think
it's a bad idea but would like to think more about it.  For cpuset, it
was needed because configuration was so interwoven with the effective
masks, but we don't generally do this for other min/max or weight
knobs, all of which have effective hierarchical values and I'm not
quite sure about adding .effective for all of them.  It could be that
that's what we end up doing eventually but I'd like to think a bit
more about it.

Thanks.

-- 
tejun