From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964784AbXDLTob (ORCPT ); Thu, 12 Apr 2007 15:44:31 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S965044AbXDLTob (ORCPT ); Thu, 12 Apr 2007 15:44:31 -0400 Received: from gw.goop.org ([64.81.55.164]:45301 "EHLO mail.goop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S964784AbXDLTo3 (ORCPT ); Thu, 12 Apr 2007 15:44:29 -0400 Message-ID: <461E8BF9.5000402@goop.org> Date: Thu, 12 Apr 2007 12:43:53 -0700 From: Jeremy Fitzhardinge User-Agent: Thunderbird 1.5.0.10 (X11/20070302) MIME-Version: 1.0 To: Andrew Morton CC: Andi Kleen , 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 References: <20070411162904.232696302@mvista.com> <200704121136.03098.ak@novell.com> <20070412092348.70a4de05.akpm@linux-foundation.org> <200704121845.39961.ak@novell.com> <20070412100039.00ace23f.akpm@linux-foundation.org> <461E6FA7.5080605@goop.org> <20070412105559.385789dd.akpm@linux-foundation.org> In-Reply-To: <20070412105559.385789dd.akpm@linux-foundation.org> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Andrew Morton wrote: > blktrace. I've seen a couple of trace/debug-style things which use > sched_clock for timestamping event collection. I think lttng does exotic > things with TSCs, performing private skew correction, although that might > have changed now. > I'm not worried about things using the tsc directly. But since we hook into sched_clock, anyone using it is going to get the pv_ops backend's behaviour, which is targeted at making the scheduler work properly rather than all these secondary uses. J