From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756147AbZA2CGu (ORCPT ); Wed, 28 Jan 2009 21:06:50 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753237AbZA2CGl (ORCPT ); Wed, 28 Jan 2009 21:06:41 -0500 Received: from n4a.bullet.mail.ac4.yahoo.com ([76.13.13.67]:36493 "HELO n4a.bullet.mail.ac4.yahoo.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1752522AbZA2CGk (ORCPT ); Wed, 28 Jan 2009 21:06:40 -0500 X-Yahoo-Newman-Property: ymail-3 X-Yahoo-Newman-Id: 724564.82350.bm@omp109.mail.ac4.yahoo.com DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=ymail.com; h=X-YMail-OSG:Received:X-Mailer:Date:From:Reply-To:Subject:To:Cc:In-Reply-To:MIME-Version:Content-Type:Message-ID; b=T1YCFPiTZLlvFIUC23yX6JMe0sDvZgxh1qJTsUJoL0cjm4l08h0Yz7PIq3ksCjnytOjz0m5sQclAz8zLCJa1qtxnVWBvLAr4UlSx5WWw2XuztdbKuAw5JnfvSRypuY9zaalUH64Mh5mjOzWon4jkko18/2vfpde81QCQdV3eXgY=; X-YMail-OSG: JCloMg4VM1nHzN3gW_nUQe.hrRaMGHoRQSdssmCsvBdcxguMOM_yIU01muADlMJ6DFxRcriwO2tCgL4eNSarjAFnqoUU_uO9BCd5JNHTaecGSHXu4vbMEBB5LNBWekyI4DB4jy3_N2JKiDecBEDKHm8yZSfXWx8tqpeDnfeSWAM.kPEpHbxIfe2YiT0SSY2NagfXuUc- X-Mailer: YahooMailWebService/0.7.260.1 Date: Wed, 28 Jan 2009 18:06:37 -0800 (PST) From: Xiaoning Ding Reply-To: dingxn@ymail.com Subject: Re: a question about p4_clockmod module on Xeon quad core processors To: Dave Jones Cc: linux-kernel@vger.kernel.org In-Reply-To: <20090128210200.GA19527@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Message-ID: <630240.73962.qm@web59913.mail.ac4.yahoo.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Thanks for the correction. My experiments need to reduce CPU speed. However, I can only reduce the speed by about 30% (from 2.67GHz to 2GHz) with ACPI. That is not enough for the experiments. p4-clockmod has not been removed from 2.6.29. It is under the same directory as acpi-cpufreq (arch/x86/kernel/cpu/cpufreq). So I thought it was an alternative approach. But I could not get it loaded. Xiaoning --- On Wed, 1/28/09, Dave Jones wrote: > From: Dave Jones > Subject: Re: a question about p4_clockmod module on Xeon quad core processors > To: "Xiaoning Ding" > Cc: linux-kernel@vger.kernel.org > Date: Wednesday, January 28, 2009, 9:02 PM > On Tue, Jan 27, 2009 at 12:17:25PM -0800, Xiaoning Ding > wrote: > > Hi list, > > > > I have tried the p4-clockmod module in Linux kernel > 2.6.29 on Xeon 5355 quad-core CPUs with no luck. It seems > current p4-clockmod driver still cannot support Intel Quad > core processors, right? > > > > I know I can also use acpi-cpufreq. It can only scale > down the frequence from 2.67GHz to 2GHz. But I need some > lower frequencies for some experiments. > > p4-clockmod doesn't change the processor frequency. > Because of common misconceptions like this, the user > interface has been removed. > > In 2.6.29, the clock modulation code is called directly > from ACPI > whenever thermal events indicate that throttling is > necessary. > > Dave > > -- > http://www.codemonkey.org.uk