On Wed 2009-07-08 19:41:23, Corrado Zoccolo wrote: > Hi Matthew, > > On Wed, Jul 8, 2009 at 6:10 PM, Matthew Garrett<mjg@xxxxxxxxxx> wrote: > > On Wed, Jul 08, 2009 at 03:56:33PM +0200, Corrado Zoccolo wrote: > >> The patch introduces a new sysfs tunable cpufreq/ondemand/freq_step, > >> as found in conservative governor, to chose the frequency increase step, > >> expressed as percentage (default = 100 is previous behaviour). > >> > >> This allows fine tuning powersaving on mobile CPUs, since smaller steps will allow to: > >> * absorb punctual load spikes > >> * stabilize at the needed frequency, without passing for more power consuming states, and > > > > Is this a measured powersaving? The ondemand model is based on the > > assumption that the idle state is disproportionately lower in power than > > any running state, and therefore it's more sensible to run flat out for > > short periods of time than run at half speed for longer. Is this > > inherently flawed, or is it an artifact of differences in your processor > > design? Different processors behave differently -- that assumption is wrong at least for old athlon64s... Those have power-hungry idle states, and 4x power consumption at 2x frequency.... (Original Intel speedstep was similar iirc). Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html -- To unsubscribe from this list: send the line "unsubscribe cpufreq" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
