From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751682AbXDLUP0 (ORCPT ); Thu, 12 Apr 2007 16:15:26 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751696AbXDLUP0 (ORCPT ); Thu, 12 Apr 2007 16:15:26 -0400 Received: from mail.suse.de ([195.135.220.2]:51376 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751661AbXDLUPZ (ORCPT ); Thu, 12 Apr 2007 16:15:25 -0400 From: Andi Kleen Organization: SUSE Linux Products GmbH, Nuernberg, GF: Markus Rex, HRB 16746 (AG Nuernberg) To: Jeremy Fitzhardinge Subject: Re: [PATCH] i386 tsc: remove xtime_lock'ing around cpufreq notifier Date: Thu, 12 Apr 2007 22:15:04 +0200 User-Agent: KMail/1.9.6 Cc: Andrew Morton , Daniel Walker , linux-kernel@vger.kernel.org, johnstul@us.ibm.com, tglx@linutronix.de References: <20070411162904.232696302@mvista.com> <200704121945.54053.ak@novell.com> <461E8CAA.3020902@goop.org> In-Reply-To: <461E8CAA.3020902@goop.org> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200704122215.04499.ak@suse.de> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org > They could be huge differences - unbounded, in fact. It would make > printk fairly hard to interpret, I would think. The only benefit to > using sched_clock in printk is that if you're using it to work out the > startup latencies you won't be confused by stolen time. But I think > that's a fairly small benefit compared to the disadvantage of not being > able to meaningfully compare the timestamps on two printk messages. Ok so the right solution would be a separate printk_clock() that is implemented as the native sched_clock() even on Xen/VMI. Should be a SMOP. -Andi