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Date: Fri, 27 Jan 2012 14:46:40 +0530
From: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
To: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Vincent Guittot <vincent.guittot@linaro.org>,
        Indan Zupancic <indan@nul.nu>, Youquan Song <youquan.song@intel.com>,
        Ingo Molnar <mingo@elte.hu>, Arjan van de Ven <arjan@linux.intel.com>,
        Suresh Siddha <suresh.b.siddha@intel.com>,
        Linux Kernel <linux-kernel@vger.kernel.org>
Subject: Re: [RFC PATCH v1 1/2] sched: unified sched_powersavings sysfs
 tunable
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* Peter Zijlstra <a.p.zijlstra@chello.nl> [2012-01-25 15:57:26]:

> On Mon, 2012-01-16 at 21:52 +0530, Vaidyanathan Srinivasan wrote:
> > +enum powersavings_level {
> > +       POWERSAVINGS_DISABLED = 0,      /* Max performance */
> > +       POWERSAVINGS_DEFAULT,           /* Kernel default policy, automatic powersave */
> > +                                       /* vs performance tradeoff */
> > +       POWERSAVINGS_MAX                /* Favour power savings over peformance */
> >  }; 
> 
> I don't like that, I can get, OFF, AUTO, ON, but to overload that with
> different policies for AUTO and ON just reeks.

How about this:

enum powersavings_level {
       POWERSAVINGS_OFF = 0,           /* Max performance */
       POWERSAVINGS_AUTO,              /* Kernel default policy, automatic powersave */
                                       /* vs performance tradeoff */
       POWERSAVINGS_ON                 /* Max power savings */
}; 
 
Basically AUTO is where we have a 'policy' or heuristics, but simple
straight forward decisions for OFF and ON case. 

--Vaidy