Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750710AbVLEBQb (ORCPT ); Sun, 4 Dec 2005 20:16:31 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750718AbVLEBQb (ORCPT ); Sun, 4 Dec 2005 20:16:31 -0500 Received: from mx1.redhat.com ([66.187.233.31]:37527 "EHLO mx1.redhat.com") by vger.kernel.org with ESMTP id S1750710AbVLEBQb (ORCPT ); Sun, 4 Dec 2005 20:16:31 -0500 Date: Sun, 4 Dec 2005 20:16:11 -0500 From: Dave Jones To: Lee Revell Cc: Andi Kleen , Venkatesh Pallipadi , Andrew Morton , cpufreq , linux-kernel Subject: Re: [PATCH] CPU frequency display in /proc/cpuinfo Message-ID: <20051205011611.GA12664@redhat.com> Mail-Followup-To: Dave Jones , Lee Revell , Andi Kleen , Venkatesh Pallipadi , Andrew Morton , cpufreq , linux-kernel References: <20051202181927.GD9766@wotan.suse.de> <20051202104320.A5234@unix-os.sc.intel.com> <20051204164335.GB32492@isilmar.linta.de> <20051204183239.GE14247@wotan.suse.de> <1133725767.19768.12.camel@mindpipe> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1133725767.19768.12.camel@mindpipe> User-Agent: Mutt/1.4.2.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1582 Lines: 32 On Sun, Dec 04, 2005 at 02:49:26PM -0500, Lee Revell wrote: > On Sun, 2005-12-04 at 19:32 +0100, Andi Kleen wrote: > > On Sun, Dec 04, 2005 at 05:43:35PM +0100, Dominik Brodowski wrote: > > > On Fri, Dec 02, 2005 at 10:43:20AM -0800, Venkatesh Pallipadi wrote: > > > > The patch below changes this to: > > > > Show the last known frequency of the particular CPU, when cpufreq is present. If > > > > cpu doesnot support changing of frequency through cpufreq, then boot frequency > > > > will be shown. The patch affects i386, x86_64 and ia64 architectures. > > > > > > Looks good to me -- however, might this affect userspace cpufreq tools? I'd > > > > They normally use /sys anyways. > > Wrong, lots of userspace programs that need to know the CPU speed get it > from /proc/cpuinfo. It would be nice if there were a better API. I can't think of a single valid reason why a program would want to know the MHz rating of a CPU. Given that it's a) approximate, b) subject to change due to power management, c) completely nonsensical across CPU vendors, and d) only one of many variables regarding CPU performance, any program that bases any decision on the values found by parsing that field of /proc/cpuinfo is utterly broken beyond belief. Adding any other interface to obtain this value is equally as broken. Dave - 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/