From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030457AbXDLRBp (ORCPT ); Thu, 12 Apr 2007 13:01:45 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1030474AbXDLRBp (ORCPT ); Thu, 12 Apr 2007 13:01:45 -0400 Received: from smtp.osdl.org ([65.172.181.24]:49850 "EHLO smtp.osdl.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1030457AbXDLRBn (ORCPT ); Thu, 12 Apr 2007 13:01:43 -0400 Date: Thu, 12 Apr 2007 10:00:39 -0700 From: Andrew Morton To: Andi Kleen Cc: Daniel Walker , linux-kernel@vger.kernel.org, johnstul@us.ibm.com, tglx@linutronix.de Subject: Re: [PATCH] i386 tsc: remove xtime_lock'ing around cpufreq notifier Message-Id: <20070412100039.00ace23f.akpm@linux-foundation.org> In-Reply-To: <200704121845.39961.ak@novell.com> References: <20070411162904.232696302@mvista.com> <200704121136.03098.ak@novell.com> <20070412092348.70a4de05.akpm@linux-foundation.org> <200704121845.39961.ak@novell.com> X-Mailer: Sylpheed version 2.2.7 (GTK+ 2.8.17; x86_64-unknown-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 12 Apr 2007 18:45:39 +0200 Andi Kleen wrote: > > > I was proposing that i386 and x86_64 be given a new, lockless, > > high-resolution printk_clock(). Presently x86 uses the default > > printk_clock(), which uses sched_clock(). Presumably copying the > > pre-x86_64-mm-sched-clock-share.patch version of sched_clock() into > > printk_clock() will suffice. > > Ok. I think it's better to just fix sched_clock() again than to > add another one. I can probably > eliminate the ktime_get() and use something based on jiffies. That will > be inaccurate for the instable case of course. hm. People (ab)use sched_clock() for all sorts of things nowadays. I wouldn't do anything to degrade it just on behalf of printk-timestamping.