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Date: Fri, 26 Feb 2016 10:14:46 +0100
From: Peter Zijlstra <peterz@infradead.org>
To: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>,
        Steve Muckle <steve.muckle@linaro.org>, Ingo Molnar <mingo@redhat.com>,
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        Juri Lelli <Juri.Lelli@arm.com>,
        Patrick Bellasi <patrick.bellasi@arm.com>,
        Michael Turquette <mturquette@baylibre.com>
Subject: Re: [RFCv7 PATCH 01/10] sched: Compute cpu capacity available at
 current frequency
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On Fri, Feb 26, 2016 at 02:37:19AM +0100, Rafael J. Wysocki wrote:

> That's all correct, but my question should rather be: is arch the right
> granularity?
> 
> In theory, there may be ARM64-based platforms using ACPI and behaving
> like x86 in that respect in the future.

Ah, so I started these hooks way before the cpufreq/cpuidle etc.
integration push.

Maybe we should look at something like that, but performance is really
critical, you most definitely do not want 3 indirections just because
abstract framework crap, that's measurable overhead on these callsites.

Hence the current inline with constant value or single function call.
And if archs would want a selector, I would recommend boot time call
instruction rewrites a-la alternatives/paravirt.