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Date:   Wed, 2 Dec 2020 17:58:28 +0100
From:   Peter Zijlstra <peterz@infradead.org>
To:     Mel Gorman <mgorman@suse.de>
Cc:     "Rafael J. Wysocki" <rjw@rjwysocki.net>,
        Ingo Molnar <mingo@kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Vincent Guittot <vincent.guittot@linaro.org>,
        Morten Rasmussen <morten.rasmussen@arm.com>,
        dietmar.eggemann@arm.com, patrick.bellasi@matbug.net,
        lenb@kernel.org, linux-kernel@vger.kernel.org,
        valentin.schneider@arm.com, ionela.voinescu@arm.com,
        qperret@google.com, viresh.kumar@linaro.org
Subject: Re: [RFC] Documentation/scheduler/schedutil.txt
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On Wed, Dec 02, 2020 at 04:45:31PM +0000, Mel Gorman wrote:

> > > It's less obvious what the consequence is unless the reader manages to
> > > tie the IO-wait comment in "Schedutil / DVFS" to this section.
> > 
> > I'm not entirely sure I follow. The purpose of UTIL_EST is to avoid
> > ramp-up issues and isn't related to IO-wait boosting.
> > 
> 
> I mixed up the example. Historically io-wait boosting was one way of
> avoiding DVFS ramp-up issues but now that I reread it, it's best to leave
> it general like you already have in your current version.

So IO-wait boosting is an interesting case; as it captures something not
present in the rest of the model, namely interaction.

There's also that series of patches that does the cpu/gpu interaction
thing.

It would be worth expanding on it, but I didn't have it in me to dig
through the archives to get a coherent description of the current state
of things. Something left todo later...