Messages in this thread | | | Date | Mon, 14 Jul 2008 08:26:44 +0200 | From | Pavel Machek <> | Subject | Re: v2.6.26-rc7: Negative powertop values |
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On Sun 2008-07-13 08:35:59, Arjan van de Ven wrote: > Pavel Machek wrote: >> On Tue 2008-07-08 06:52:51, Arjan van de Ven wrote: >>> On Sun, 6 Jul 2008 21:48:45 +0200 >>> Pavel Machek <pavel@suse.cz> wrote: >>> >>>>> [I assume you know that doing a software unplug you burn more power >>>>> than by leaving the cpu idle] >>>> We should really fix that one day... >>> yeah but it's incredibly hard to get right (in the light of the bios >>> constantly changing what our allowed C-states are)... and the best case >> >> What can happen there? So BIOS decides C4 may no longer be cool idea >> because we have AC power now, but that does not mean C4 stops working, >> right? > > or it decides that your voltage regulator needs to operate in a certain mode and the voltage for C4 is no longer > available. or .. or ... > >> >> How is changing allowed C-states list supposed to work, anyway? I >> mean, we may be in one of those on other CPU when BIOS decides to >> change the list... > > you get an interrupt to notify you of the change ;-)
But that's too late, right? You may be actively using that Cstate on another CPU... Pavel
-- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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