From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754081AbYIWGdi (ORCPT ); Tue, 23 Sep 2008 02:33:38 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752499AbYIWGdb (ORCPT ); Tue, 23 Sep 2008 02:33:31 -0400 Received: from pih-relay06.plus.net ([212.159.14.19]:47329 "EHLO pih-relay06.plus.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752336AbYIWGda (ORCPT ); Tue, 23 Sep 2008 02:33:30 -0400 Message-ID: <48D88DB4.9020003@yahoo.com> Date: Tue, 23 Sep 2008 07:33:24 +0100 From: Sitsofe Wheeler User-Agent: Thunderbird 2.0.0.16 (Macintosh/20080707) MIME-Version: 1.0 To: Ingo Molnar CC: Peter Zijlstra , Arjan van de Ven , linux-kernel@vger.kernel.org, Steven Rostedt Subject: Re: How how latent should non-preemptive scheduling be? References: <48D39312.9000400@yahoo.com> <20080922115749.GE14301@elte.hu> In-Reply-To: <20080922115749.GE14301@elte.hu> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Plusnet-Relay: af6a8bb78135725b2edaf60b7b90a3cc Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Ingo Molnar wrote: > well, since they went away after you enabled CONFIG_PREEMPT=y, they are > definitely in-kernel latencies, not any external SMM latencies. > > I.e. they are inherently fixable. Could you enable: > > CONFIG_DYNAMIC_FTRACE=y > CONFIG_FTRACE_MCOUNT_RECORD=y > > that should make the traces a lot more verbose - every kernel function > executed in the latency path will be logged. That way we'll be able to > say which one takes that long. I do not appear to have the CONFIG_FTRACE_MCOUNT_RECORD option in 2.6.27rc7. Is it an option that is only in -tip ? -- Sitsofe | http://sucs.org/~sits/