Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755414AbZA2CLy (ORCPT ); Wed, 28 Jan 2009 21:11:54 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754891AbZA2CLn (ORCPT ); Wed, 28 Jan 2009 21:11:43 -0500 Received: from n4.bullet.mail.ac4.yahoo.com ([76.13.13.28]:42322 "HELO n4.bullet.mail.ac4.yahoo.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1758378AbZA2CLm (ORCPT ); Wed, 28 Jan 2009 21:11:42 -0500 X-Yahoo-Newman-Property: ymail-3 X-Yahoo-Newman-Id: 983734.86665.bm@omp106.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=E7APyc0r51nCi4l2Hj0kXdel9iSsO6bbtoOFN1fKdNxP9U5EAqO4LtASBTwPWmeo9hGPzR2RL/6hU8U4w6yQBh6OinUJB6FvKbUoVpyzr34C4qCidbhnk9ZXfSyyqn8J469xAsUzWv6hZRw1bGXQjKpKjyUADJbiBJPYXl/OMUI=; X-YMail-OSG: gDkmHv4VM1l3RIJUtWCaPKKQmpf_gb90lf.7XwjzJ6Vi7HW61sqms8eKjE64ZafLhBBt4e5oxqQorkNZEDd_p2D4UQz7NT7QclFByy2CXGk4.ObIUu2sBERxWLzc8dOPNWgjSjnHCQy91LIvZGGfOem9iA7iux6XmiGY_ghM.m3Ctmx9CwbAchexFmUF X-Mailer: YahooMailWebService/0.7.260.1 Date: Wed, 28 Jan 2009 18:11:40 -0800 (PST) From: Xiaoning Ding Reply-To: dingxn@ymail.com Subject: Re: a question about p4_clockmod module on Xeon quad core processors To: Wes Felter Cc: linux-kernel@vger.kernel.org In-Reply-To: <4980C8A9.6090904@felter.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Message-ID: <765076.76058.qm@web59913.mail.ac4.yahoo.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1448 Lines: 40 I installed msr-tools, but could not find detailed information on how to change cpu speed with the tools. Can you point me to detailed documentations? Or, can you share your code? Thanks! Xiaoning --- On Wed, 1/28/09, Wes Felter wrote: > From: Wes Felter > Subject: Re: a question about p4_clockmod module on Xeon quad core processors > To: dingxn@ymail.com > Cc: linux-kernel@vger.kernel.org > Date: Wednesday, January 28, 2009, 9:05 PM > 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. > > Clock modulation is quite simple; in the past I've done > it from userspace with /dev/cpu/*/msr or written my own > module to do it. I don't know if I've ever tried it > on quad-cores, but it worked on dual-core Woodcrest. (Note: > I was not trying to save energy.) > > Wes Felter - wesley@felter.org -- 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/