I use powerdevil to manage power saving under KDEmod4 on my laptop. it works fine, except for the fact that ondemand governor seems a bit slow to scale the frequency (the performance governor, which simply keeps the cpu at max frequency, gives performance improvements up to 100%). When I installed Arch, before installing KDEmod and powerdevil, I followed th wiki to set up the cpufreq tools:
My question is: since I have both cpufreq and powerdevil, is it possible that the two governors are generating conflicts which slow down the cpu scaling? Or maybe cpufreq is managed or overridden by powerdevil?
Thank everyone for the help
I would think that the kde powerdevil _uses_ the cpufreq-driver whose installation was described in the mentioned wiki article. So I don't think there is a possibility for interference. Of course the cpufreq-driver needs a little time to recognize that the cpu is now used but that amount of time should be so small you won't probably recognize it.
Last edited by Erki der Loony (2009-01-23 11:59:06)
I thought about the same when I said "cpufreq is managed [...] by powerdevil". I'm aware that scaling requires time but a 100% performance improvement sounded too large to me...
Anyway, tahnks for the answer!
I apologize in advance if I may say something stupid, but isn't powerdevil only using hal and no daemon?
I use powerdevil too, but don't use the cpufreq daemon, the needed kernel modules are loaded, of course.
Since powerdevil starts only after kde is loaded I use /etc/rc.local to set the frequency to the lowest to not stay at highest frequency until I log in (cpufreq-set -f 800MHz). Other settings are done in the powerdevil systemsettings module only.
So, if the things are as SignorRossi said, there could be a problem with two cpu governors acting at the same time. Since I almost exclusively work under X I can disable the cpufreq daemon, but I'm still curious to find an answer to the question...
When I ran KDEmod4, I disabled cpufreqd and let PowerDevil do all the work. I do imagine the two would conflict. If not, it's still just wasted resources.
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