From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757649AbZA2Qc4 (ORCPT ); Thu, 29 Jan 2009 11:32:56 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753278AbZA2Qcq (ORCPT ); Thu, 29 Jan 2009 11:32:46 -0500 Received: from n6a.bullet.mail.ac4.yahoo.com ([76.13.13.69]:46505 "HELO n6a.bullet.mail.ac4.yahoo.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1753678AbZA2Qcn (ORCPT ); Thu, 29 Jan 2009 11:32:43 -0500 X-Yahoo-Newman-Property: ymail-3 X-Yahoo-Newman-Id: 299873.84551.bm@omp101.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=4cB0zxhWULcWxcfTP1q5Rs72Iw+BNaW0Fl1MaG+PHkFvW0qrdhTP5GoJar4/Q7h1VfaPJ0IcB4Kn1f5GrWnyeO52Jf6gPMC8xBK2TSV3w3Fs8XJz6Ve+eBTKlYdFxBvwyhdBK5vrOo2xny33+T7khGhUbPxyqqusRJp3nxHAaw8=; X-YMail-OSG: HteDT98VM1mXq.jXy2VyR60JRliaEv8kTo8E17BKsZiWELSLT6traC3ZuOUuT.GlL8nym8CTyHYJIBr24SxZPcEh6c2Miy.w6eBw7y5OQ1HNw1nE9LcXNThHA31rXhz83vIZXV95OuaYVYmuTZuiBUiBz9RG3Qp6Z4knrqWbFF1tpTKgRpuqpByk21cP1WFowMlTwOQ- X-Mailer: YahooMailWebService/0.7.260.1 Date: Thu, 29 Jan 2009 08:32:41 -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: <20090129024539.GA17541@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Message-ID: <213679.55387.qm@web59907.mail.ac4.yahoo.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --- On Thu, 1/29/09, 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: Thursday, January 29, 2009, 2:45 AM > [please don't top-post] > > On Wed, Jan 28, 2009 at 06:06:37PM -0800, Xiaoning Ding > wrote: > > > > > 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. > > > > > 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. > > The ACPI P-states are nearly always correct, so you > won't be > able to go below 2GHz on this system. That's true for changing P-States with ACPI. But I can still get slower speed with clock modulation, right? > > 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. > > The driver is present, the _user interface_ has been > removed. The module cannot loaded on Xeon 5355. If I can load it, I hope I can find a method to use it. > Dave > > -- > http://www.codemonkey.org.uk > -- > 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/