Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756836AbYFBChd (ORCPT ); Sun, 1 Jun 2008 22:37:33 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753773AbYFBCh0 (ORCPT ); Sun, 1 Jun 2008 22:37:26 -0400 Received: from rv-out-0506.google.com ([209.85.198.238]:51015 "EHLO rv-out-0506.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753697AbYFBChZ (ORCPT ); Sun, 1 Jun 2008 22:37:25 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:user-agent:mime-version:to:cc:subject:references:in-reply-to:content-type:content-transfer-encoding; b=vsFf6coJDWSq4US7BKWzduF5cwwMoIlZ0OGIM+19pIAk3jVq5UYTr4nA9oKl3f46HKCloAvKGmzbTmsAw/u2XDIQl2gvMMbtt4s980YAI3cCZL1buVkoZ5GVZ9z1MKSMPaB7AgG5B9QTTdXzfyNFXk/GN1sbCnfWHJlQCYUDoaQ= Message-ID: <48435CCA.5000905@gmail.com> Date: Sun, 01 Jun 2008 21:36:58 -0500 From: Roger Heflin User-Agent: Thunderbird 2.0.0.14 (X11/20080501) MIME-Version: 1.0 To: Arjan van de Ven CC: Guntsche Michael , linux-kernel@vger.kernel.org Subject: Re: 2.6.25.x: Wrong CPU frequency (cpufreq table) with p4-clockmod References: <12C649C0-4BEF-41F1-B738-8C8CEF8AEBB8@it-loops.com> <20080530065717.44cf7414@infradead.org>

<20080601185643.3d3db64f@infradead.org> In-Reply-To: <20080601185643.3d3db64f@infradead.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2624 Lines: 58 Arjan van de Ven wrote: > On Sun, 1 Jun 2008 23:57:14 +0200 > Guntsche Michael wrote: > >> On May 30, 2008, at 16:07, Guntsche Michael wrote: >> >>> I am most interested in keeping the temperature of my CPU down, >>> which means slower fans, which means less noise. >>> The main "problem" I have is that I do not know if this is a >>> simple display issue or if I am having a more fundamental problem >>> here. >> Just FYI I found out the cause of my problem. >> >> Reverting >> http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=ed9cbcd40004904dbe61ccc16d6106a7de38c998 >> this patch resultsin the correct numbers for me. >> >> >> processor : 0 >> vendor_id : GenuineIntel >> cpu family : 15 >> model : 1 >> model name : Intel(R) Pentium(R) 4 CPU 1.70GHz >> stepping : 2 >> cpu MHz : 637.500 >> >> >> This patch was reverted because other people seem to have problems >> with it, reverting the revert does not look like a good idea either. >> But since I know now, that this is just a "display" problem and >> everything is working otherwise, I'll just patch this locally for my >> machine here. >> > > just as a side note.. you do realize that with p4-clockmod, your cpu is > still running at 1.7 GHz right? (it's just doing less work '-) From my testing, I believe the only thing that p4-clockmod does is forces an idle call when it could otherwise do work on an active process, so fullspeed and idle uses *EXACTLY* the same amount of power as p4-clockmod slower speed and idle (and therefore generates exactly the same amount of heat), the only power difference would be that if you were using p4-clockmod to slow down the cpu when it had an active running process (force the cpu to be idle a lot of the time even though it has work). Arjan's point is that if you are using p4-clockmod to slow down an idle cpu in hopes of saving power when the cpu is not being used, then it is not going to make *ANY* difference in the power usage at all. I tried it on my p4 here, and cannot see any power difference in idle/fullspeed and idle/slowspeed, this is unlike the later power saving stuff that actually does slow down the cpu frequency, and you can measure a different amount of power usage with the different clock speeds and an idle cpu. Roger -- 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/