From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756449AbZAVJa1 (ORCPT ); Thu, 22 Jan 2009 04:30:27 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754073AbZAVJaM (ORCPT ); Thu, 22 Jan 2009 04:30:12 -0500 Received: from mx3.mail.elte.hu ([157.181.1.138]:49736 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753644AbZAVJaL (ORCPT ); Thu, 22 Jan 2009 04:30:11 -0500 Date: Thu, 22 Jan 2009 10:29:42 +0100 From: Ingo Molnar To: Steven Rostedt Cc: linux-kernel@vger.kernel.org, Andrew Morton , Frederic Weisbecker , Steven Rostedt Subject: Re: [PATCH 1/5] trace: do not disable wake up tracer on output of trace Message-ID: <20090122092942.GA30467@elte.hu> References: <20090121235306.224764198@goodmis.org> <20090121235805.771064570@goodmis.org> <20090122084105.GD7438@elte.hu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090122084105.GD7438@elte.hu> User-Agent: Mutt/1.5.18 (2008-05-17) 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 * Ingo Molnar wrote: > auto-disabling latency tracing while the trace is being output is > essential. Measurement should never impact the workload that is being > measured. On the other hand - the latencies caused by tracing output itself should be quite low, correct? If not then that needs fixing too. So i've picked up your change - lets see how useful the result is. But "if it hurts, disable tracing before reading the tracing result" method you expressed is really not acceptable. Ingo