From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757596AbXL3O5z (ORCPT ); Sun, 30 Dec 2007 09:57:55 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753017AbXL3O5r (ORCPT ); Sun, 30 Dec 2007 09:57:47 -0500 Received: from mx3.mail.elte.hu ([157.181.1.138]:50650 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752380AbXL3O5r (ORCPT ); Sun, 30 Dec 2007 09:57:47 -0500 Date: Sun, 30 Dec 2007 15:53:04 +0100 From: Ingo Molnar To: Mike Galbraith Cc: tglx@linutronix.de, Maxim , Len Brown , linux-kernel@vger.kernel.org, Andrew Morton Subject: Re: [BUG] 2.6.21-rc1,2,3 regressions on my system that I found so far Message-ID: <20071230145304.GS16946@elte.hu> References: <200703161230.03712.maximlevitsky@gmail.com> <200703161919.44458.lenb@kernel.org> <200703180100.01889.maximlevitsky@gmail.com> <1174174374.13341.448.camel@localhost.localdomain> <1199001010.5452.30.camel@homer.simson.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1199001010.5452.30.camel@homer.simson.net> User-Agent: Mutt/1.5.17 (2007-11-01) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.3 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Mike Galbraith wrote: > > Is this after resume ? If yes, then something (probably BIOS) is > > fiddling with the TSC of one CPU when the resume happens. > > My P4 box has the same "problem", which is remedied by.. > - start = get_cycles_sync(); > + start = last_tsc = get_cycles_sync(); this is slightly racy - your second patch that initializes things properly is the right solution IMO. I'm wondering, if others are seeing this too, should we make this a v2.6.24 item? It's a bit late for that i think - although it shouldnt hurt. Ingo