On Thu, Dec 07, 2006 at 05:23:51PM +0100, Hendrik Sattler wrote: > Am Donnerstag 07 Dezember 2006 16:36 schrieb John Goerzen: > > I believe that we should enable CPU frequency scaling, and the ondemand > > governer, by default in etch. > > Did you read the kernel help for it?:
So, broadly speaking, you support doing something like this by default, just not the ondemand governor? > "The support for this governor depends on CPU capability to do fast frequency > switching (i.e, very low latency frequency transitions)." > The most important word is "very". I have yet to see a machine with trouble with this, though that doesn't say they couldn't exist. See, for example, Novell's comments here: http://forge.novell.com/pipermail/powersave-devel/2006-April/000478.html > > Earlier this morning, I wrote up the procedure [1] to enable CPU > > frequency scaling and the ondemand governor. It's about 3 pages, and > > not even newbie friendly at that. So the first reason is that people > > that don't know about this feature aren't prone to find it, and even if > > they find it, they aren't prone to know how to enable it. > > apt-get install cpufrequtils > cpufreq-set -g ondemand > > Really hard ;) That is completely useless unless the user has already manually figured out which cpufreq modules to load, and loaded them. I tested that before I wrote my article. It doesn't load modules for you, and nothing else does by default, either. I also grepped through the source: not an insmod or a modprobe to be found. That bit is the largest problem anyway. > > interfere with it. I've tried it all over the place. It is stable and > > reliable. > > I already had a system go off with it. Ok, it didn't have low latency > switching. If we tweak the parameters so it doesn't switch as fast, probably that could be solved, yes? Novell seems to believe that ondemand configured that way is more stable than conservative. > You REALLY should take a look at laptop-mode-tools. > They can do this for you including loading the proper modules when needed and > LOTS of other energy saving technics. I have. It is also much more invasive than this simple switch, and doesn't necessarily play nice with Gnome/KDE cpu frequency widgets, etc. Plus there are n favorite userspace daemons (laptop-mode-tools, powersaved, powernowd, cpudyn, etc, etc.). I suggested it this way because it is non-invasive and works with anything. > And you should take a look at the "conservative" governor, too. > And BTW, did you measure the power savings? My WLAN card and monitor > backlight > eat _all_ the savings and the kernel usually knows how to put the processor > to a sleep state. It makes a noticable difference on my Macbook Pro's battery life. I don't (yet) have the equipment to measure the power draw of my desktop. Note that this is not the same as a sleep state. This holds the CPU at a lower frequency until CPU utilization hits 80% (by default). -- John -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
