Subject: Re: [PATCH 1/3] Added runqueue clock normalized with cpufreq
From: Peter Zijlstra <peterz@infradead.org>
To: Harald Gustafsson <hgu1972@gmail.com>
Cc: Harald Gustafsson <harald.gustafsson@ericsson.com>,
        Dario Faggioli <faggioli@gandalf.sssup.it>,
        linux-kernel@vger.kernel.org, Ingo Molnar <mingo@elte.hu>,
        Thomas Gleixner <tglx@linutronix.de>,
        Claudio Scordino <claudio@evidence.eu.com>,
        Michael Trimarchi <trimarchi@retis.sssup.it>,
        Fabio Checconi <fabio@gandalf.sssup.it>,
        Tommaso Cucinotta <cucinotta@sssup.it>,
        Juri Lelli <juri.lelli@gmail.com>, Dario Faggioli <raistlin@linux.it>
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Date: Fri, 17 Dec 2010 16:16:47 +0100
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On Fri, 2010-12-17 at 16:06 +0100, Harald Gustafsson wrote:
> 2010/12/17 Peter Zijlstra <peterz@infradead.org>:
> > This is all assuming lowering the frequency is sensible to begin with in
> > the first place... but that's all part of the CPUfreq governor, it needs
> > to find a way to lower energy usage while conforming to the system
> > constraints.
> 
> Yes, I and you have already suggested the safe way to not lower it below
> the total dl bandwidth. But for softer use cases it might be possible to
> e.g. exclude threads with longer periods than cpufreq change periods in the
> minimum frequency.

I was more hinting at the fact that CPUfreq is at best a controversial
approach to power savings. I much prefer the whole race-to-idle
approach, its much simpler.
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