On 07/19/2011 09:59 AM, Jaroslav Skarvada wrote: > ----- Original Message ----- >> To avoid some confusion: >> >> I removed cpuspeed from Rawhide about 10 days ago. It no longer serves >> any >> purpose in Fedora and has been effectively replaced by kernel cpufreq >> stack. >> >> All cpufreq modules should now be built-in, with ondemand being the >> default >> governor in Fedora. >> >> In case you would to use a different governor and/or specific >> frequency, try the >> new cpupower.service (provieded by cpupowerutils). Most people >> shouldn't need >> this, though. >> >> See https://bugzilla.redhat.com/show_bug.cgi?id=713572 for more info. >> >> Regards, >> -- >> # Petr Sabata >> >> -- >> devel mailing list >> devel@xxxxxxxxxxxxxxxxxxxxxxx >> https://admin.fedoraproject.org/mailman/listinfo/devel > > Sad that the daemon gone. It was able to dynamically switch speed > (and save power) on systems that have CPUs with high transition > latency (e.g. old P4, some Atoms, etc.). On such systems the Actually, no... http://codemonkey.org.uk/2009/01/18/forthcoming-p4clockmod/ > So the 1.00GHz ‘frequency’ is actually “run at 2GHz, but only do work 50% of the time”. > > On the surface, this sounds like a good idea. The other 50%, the CPU is idle, so you’re saving power, right? > Not so much. In fact, you could be burning more power. The reason for this is that when the processor is sitting there doing nothing, it isn’t lower frequency, and more importantly, it very likely isn’t entering C states. So you’re burning the same amount of power, but now you’re only doing work for 50% of the time. As a result of this, your workload takes twice as long to complete. I've measured it, and Dave is right. You might get something saying "1.0Ghz" but you're not saving anything at all. -Eric -- devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxxx https://admin.fedoraproject.org/mailman/listinfo/devel
