From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S265227AbUBIObv (ORCPT ); Mon, 9 Feb 2004 09:31:51 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S265228AbUBIObv (ORCPT ); Mon, 9 Feb 2004 09:31:51 -0500 Received: from poup.poupinou.org ([195.101.94.96]:24119 "EHLO poup.poupinou.org") by vger.kernel.org with ESMTP id S265227AbUBIObt (ORCPT ); Mon, 9 Feb 2004 09:31:49 -0500 Date: Mon, 9 Feb 2004 15:31:46 +0100 To: Dumitru Ciobarcianu Cc: Georg M?ller , linux-kernel@vger.kernel.org Subject: Re: cpufreq - less possible freqs with 2.6.2 and P4M Message-ID: <20040209143146.GA16218@poupinou.org> References: <402562D4.7010706@gmx.net> <402656CB.7070701@gmx.net> <1076256735.1840.8.camel@LNX.iNES.RO> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1076256735.1840.8.camel@LNX.iNES.RO> User-Agent: Mutt/1.5.4i From: Bruno Ducrot Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Feb 08, 2004 at 06:12:15PM +0200, Dumitru Ciobarcianu wrote: > On Sun, 2004-02-08 at 16:33 +0100, Georg M??ller wrote: > > M??ns Rullg??rd wrote: > > > Which cpufreq module are you using? With p4-clockmod I get lots of > > > choices, with acpi only the two you mentioned. > > > > > > > Ok, that works. With P4 clockmod only there are the freqs I wanted :-) > > But I don't know it's having the effect you desire... :) > > By monitoring /proc/acpi/battery/*/state ("present rate" key) I found > that by using p4-clockmod at the lovest rate the processor permits, it's > actually using more energy than by using speedstep_ich (only two levels > of frequency). > > I don't know if this is a bug of p4-clockmod or a hw bug in my machine > though... can you please check in your machine? p4-clockmod offer only the possibility to throtte the cpu (and therefore you can get a kind of frequency setting when you change the duty cycle), but it do not scale voltage for the processor, whereas speedstep-ich will offer you the possibility to scale voltage and frequency by changing directly the core multiplier. In fact, if you have at least power control for the processor via ACPI (look into /proc/acpi/processor/????/power), and your machine support at least the power state C2, and if you are using the p4-clockmod, or anything that do throttle the processor, you reduce the windows time when the processor can enter at least this C2 power state, and this may actually consume *more* power than you would expect, especially if the system is mostly idle. Cheers, -- Bruno Ducrot -- Which is worse: ignorance or apathy? -- Don't know. Don't care.