From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752277AbXCaKCN (ORCPT ); Sat, 31 Mar 2007 06:02:13 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752741AbXCaKCN (ORCPT ); Sat, 31 Mar 2007 06:02:13 -0400 Received: from one.firstfloor.org ([213.235.205.2]:54023 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752277AbXCaKCN (ORCPT ); Sat, 31 Mar 2007 06:02:13 -0400 Date: Sat, 31 Mar 2007 12:02:09 +0200 From: Andi Kleen To: Stephane Eranian Cc: Andi Kleen , linux-kernel@vger.kernel.org, perfmon@napali.hpl.hp.com Subject: Re: exposing FSB clock speed in /sys Message-ID: <20070331100209.GA17761@one.firstfloor.org> References: <20070330153937.GC16059@frankl.hpl.hp.com> <20070331081832.GB17535@frankl.hpl.hp.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20070331081832.GB17535@frankl.hpl.hp.com> User-Agent: Mutt/1.4.2.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org > I am not interested in older processors, but I think for all recent Intel > processors, there is a fairly simple algorithm to get the frequency using > a couple of MSRs (including MSR_IA32_EBL_CR_POWERON or MSR_FSB_FREQ). Hmm, maybe make it an own driver that creates the sysfs entries somewhere. I don't think it's useful enough for the main kernel. But what happens during power saving that may lower the frequency? Wouldn't you need update events for that? That might complicate it. > > Don't we already have /sys entries that exits only for certain processors > or platforms? Yes. > I think the Opteron have HYPERTRANSPORT-related events which could be used > to obtain similar metrics. Yes, but you usually don't need the frequency. -Andi