On Wed, Jul 08, 2009 at 07:41:23PM +0200, Corrado Zoccolo wrote: > Hi Matthew, > > 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? > > The flawed assumption is that running at doubled frequency halves the > completion time. > On cpus that can change the core speed without impacting the > memory-cache bandwidth > (i.e. the Pentium M), workloads that access lot of memory go at the > same speed at > maximum and minimum frequency. > Now I see new CPUs that can flush their cache during deep idle states (Atoms), > this aggravates the aforementioned problem, rendering the high > frequency state much less appetible. Do you have numbers to support this? What effect does the ramping up have on user-visible latency? -- Matthew Garrett | mjg59@xxxxxxxxxxxxx -- 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
