linux-kernel - Re: [PATCH 6/8] cpufreq/schedutil: sum per-sched class utilization

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Message-ID: <56E9A3FD.9050309@linaro.org>
Date:	Wed, 16 Mar 2016 11:20:45 -0700
From:	Steve Muckle <steve.muckle@...aro.org>
To:	Peter Zijlstra <peterz@...radead.org>,
	Michael Turquette <mturquette@...libre.com>
Cc:	rjw@...ysocki.net, linux-kernel@...r.kernel.org,
	linux-pm@...r.kernel.org, Juri.Lelli@....com,
	morten.rasmussen@....com, dietmar.eggemann@....com,
	vincent.guittot@...aro.org,
	Michael Turquette <mturquette+renesas@...libre.com>
Subject: Re: [PATCH 6/8] cpufreq/schedutil: sum per-sched class utilization

On 03/16/2016 12:38 AM, Peter Zijlstra wrote:
> Somewhere in the giant discussions I mentioned that we should be looking
> at a CPPC like interface and pass {min,max} tuples to the cpufreq
> selection thingy.
> 
> In that same discussion I also mentioned that we must compute min as the
> hard dl reservation, but that for max we can actually use the avg dl +
> avg rt + avg cfs.
> 
> That way there is far more room for selecting a sensible frequency.

Doesn't the above min/max policy mean that the platform will likely
underserve the task load? If avg dl+rt+cfs represents our best estimate
of the work to be done, I would think that should be the min.