linux-kernel - Re: [PATCH v2 01/12] sched/core: uclamp: extend sched

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Message-ID: <20180718170226.GA21148@joelaf.mtv.corp.google.com>
Date:   Wed, 18 Jul 2018 10:02:26 -0700
From:   Joel Fernandes <joel@...lfernandes.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>,
        Tejun Heo <tj@...nel.org>,
        "Rafael J . Wysocki" <rafael.j.wysocki@...el.com>,
        Viresh Kumar <viresh.kumar@...aro.org>,
        Vincent Guittot <vincent.guittot@...aro.org>,
        Paul Turner <pjt@...gle.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>
Subject: Re: [PATCH v2 01/12] sched/core: uclamp: extend sched_setattr to
 support utilization clamping

On Wed, Jul 18, 2018 at 09:42:18AM +0100, Patrick Bellasi wrote:
> On 17-Jul 10:50, Joel Fernandes wrote:
> > On Mon, Jul 16, 2018 at 09:28:55AM +0100, Patrick Bellasi wrote:
> 
> [...]
> 
> > > diff --git a/init/Kconfig b/init/Kconfig
> > > index 041f3a022122..1d45a6877d6f 100644
> > > --- a/init/Kconfig
> > > +++ b/init/Kconfig
> > > @@ -583,6 +583,25 @@ config HAVE_UNSTABLE_SCHED_CLOCK
> > >  config GENERIC_SCHED_CLOCK
> > >  	bool
> > >  
> > > +menu "Scheduler features"
> > > +
> > > +config UCLAMP_TASK
> > > +	bool "Enable utilization clamping for RT/FAIR tasks"
> > > +	depends on CPU_FREQ_GOV_SCHEDUTIL
> > 
> > Does it make sense to depend on this? One could turn off schedutil and then
> > uclamp can't be used for any other purpose (big.LITTLE task placement etc)?
> 
> You right, utilization clamping is _going_ to target tasks placement.
> But, the support currently posted in this series is just for OPP
> biasing. Thus, it would not make sense to enabled it when schedutil
> is not available.
> 
> My idea was to keep this dependency while we finalize these bits.
> Once we move on to the tasks placement biasing, we will remove this
> dependency too.
> 
> Does that makes sense?

Yes, that's fine with me.