Messages in this thread | | | Date | Fri, 24 Feb 2006 23:24:56 -0500 | From | Dave Jones <> | Subject | Re: Status of X86_P4_CLOCKMOD? |
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On Sat, Feb 25, 2006 at 02:57:22AM +0100, Johannes Stezenbach wrote: > On Thu, Feb 23, 2006, Dave Jones wrote: > > On Thu, Feb 23, 2006 at 08:59:37PM +0100, Adrian Bunk wrote: > > > And if the option is mostly useless, what is it good for? > > > > It's sometimes useful in cases where the target CPU doesn't have any better > > option (Speedstep/Powernow). The big misconception is that it > > somehow saves power & increases battery life. Not so. > > All it does is 'not do work so often'. The upside of this is > > that in some situations, we generate less heat this way. > > Doesn't less heat imply less power consumption?
Not really. The only energy you're saving is that your CPU fan will turn slightly slower, which is probably going to be < 1W of difference. Generated heat drop in a large room of servers *may* mean the aircon has less to do, but I'd be surprised if it made a noticable difference.
> - after some minutes of idling without user activity > go into lowest power mode (could be triggered > from xscreensaver) > - at the slightest hint of user activity or CPU load jump > back to max performance mode > (- optionally use intermediate clock mod steps for > non-interactive loads, but I'm not convinced it's > worth it)
You should be able to modify cpuspeed or some other userspace governor to do this quite easily.
Dave
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