From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762186AbXHAS5w (ORCPT ); Wed, 1 Aug 2007 14:57:52 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752474AbXHAS5n (ORCPT ); Wed, 1 Aug 2007 14:57:43 -0400 Received: from one.firstfloor.org ([213.235.205.2]:51436 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751852AbXHAS5n (ORCPT ); Wed, 1 Aug 2007 14:57:43 -0400 Date: Wed, 1 Aug 2007 20:57:41 +0200 From: Andi Kleen To: Christoph Lameter Cc: Andi Kleen , linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/7] Simple Performance Counters: x86_64 support Message-ID: <20070801185741.GD20713@one.firstfloor.org> References: <11859243121617-git-send-email-clameter@sgi.com> <20070801182611.GB20713@one.firstfloor.org> <20070801184026.GC20713@one.firstfloor.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4.2.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Aug 01, 2007 at 11:45:39AM -0700, Christoph Lameter wrote: > On Wed, 1 Aug 2007, Andi Kleen wrote: > > > > It is certainly interesting to compare alternative ways of handling the > > > instruction streams by various processors or models of processors. > > > > Well you have to do a lot more work then to handle instable TSCs then. > > I have been using this for 2 years. It works fine for my purposes. That might be on your systems, but for a mainline submission the standards are higher. > > > In particular the frequencies can be different between CPUs, they > > change (which you can catch with cpufreq notifiers) and during the > > cpufreq change period they're instable (as in you can't tell for > > some time which frequency they're currently running at and they > > might be running immediate frequencies) > > Well then simply make sure that they do not change while you measure. That would be a merge blocker in my opinion. Suitable for local hacks, but nothing we want in tree. -Andi