Re: CPUFreq dynamic speed governor, take 2.

[Dominik Brodowski <linux@brodo.de>]

On Tue, Nov 04, 2003 at 11:24:26AM +0100, Ducrot Bruno wrote:
> > What about +/- 5 % of cpuinfo->max_freq? or +/- 10 % of (policy->max_freq -
> > policy->min_freq). I think the governor does not need to know of supported
> > frequencies: the governor says "I need at least n % of processing 
> > power" == "I need m bogomips of processing power" == (o, CPUFREQ_RELATION_L)
> > or it says "I need no more than..." == (o, CPUFREQ_RELATION_H)
> > 
> 
> Most of the demand based stuff I see seems to need more "I need to 
> go up/down one step."  I am not sure that it is a bad design.

What if there are thousand steps, or even more [like for the geode driver]?
Then this approach is badly broken.

> Or else, you loose probably the speedstep stuff for example (something
> like go up 10%, not enough, go up 10%, etc.).

You might miss some intermediate steps if you select a too large interval
here. However, there are other algorithms which calculate a "needed CPU
percentage" directly, and they won't miss any speedstep state.

	Dominik