Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756686AbYGNG0R (ORCPT ); Mon, 14 Jul 2008 02:26:17 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753047AbYGNG0G (ORCPT ); Mon, 14 Jul 2008 02:26:06 -0400 Received: from gprs189-60.eurotel.cz ([160.218.189.60]:38658 "EHLO gprs189-60.eurotel.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752734AbYGNG0F (ORCPT ); Mon, 14 Jul 2008 02:26:05 -0400 Date: Mon, 14 Jul 2008 08:26:44 +0200 From: Pavel Machek To: Arjan van de Ven Cc: Vegard Nossum , Ingo Molnar , Peter Zijlstra , Linux Kernel Mailing List Subject: Re: v2.6.26-rc7: Negative powertop values Message-ID: <20080714062644.GE31949@elf.ucw.cz> References: <19f34abd0806211216y4695c532ndb4935082bd8ea1@mail.gmail.com> <20080621141615.51f7100c@linux.intel.com> <20080706194845.GA5617@ucw.cz> <20080708065251.1d7d681f@linux.intel.com> <20080713115818.GA7517@elf.ucw.cz> <487A20DF.7060701@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <487A20DF.7060701@linux.intel.com> X-Warning: Reading this can be dangerous to your mental health. User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1518 Lines: 38 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 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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/