From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753648AbYKLNBk (ORCPT ); Wed, 12 Nov 2008 08:01:40 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751826AbYKLNBa (ORCPT ); Wed, 12 Nov 2008 08:01:30 -0500 Received: from mx3.mail.elte.hu ([157.181.1.138]:38066 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751965AbYKLNBa (ORCPT ); Wed, 12 Nov 2008 08:01:30 -0500 Date: Wed, 12 Nov 2008 14:01:22 +0100 From: Ingo Molnar To: Steven Rostedt Cc: Frederic Weisbecker , Linux Kernel Subject: Re: [PATCH 2/2] tracing/fastboot: Use the ring-buffer timestamp for initcall entries Message-ID: <20081112130122.GA23798@elte.hu> References: <491A062A.8080406@gmail.com> <20081112092548.GE4748@elte.hu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: 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,DNS_FROM_SECURITYSAGE autolearn=no SpamAssassin version=3.2.3 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] 0.0 DNS_FROM_SECURITYSAGE RBL: Envelope sender in blackholes.securitysage.com Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Steven Rostedt wrote: > > On Wed, 12 Nov 2008, Ingo Molnar wrote: > > > > > * Frederic Weisbecker wrote: > > > > > Impact: Split the boot tracer entries in two parts: call and return > > > > > > Now that we are using the sched tracer from the boot tracer, we want > > > to use the same timestamp than the ring-buffer to have consistent > > > time captures between sched events and initcall events. So we get > > > rid of the old time capture by the boot tracer and split the > > > initcall events in two parts: call and return. This way we have the > > > ring buffer timestamp of both. > > > > > > There is an example of a trace in attachment. > > > > > > Signed-off-by: Frederic Weisbecker > > > --- > > > include/trace/boot.h | 31 ++++++++--- > > > init/main.c | 32 ++++++------ > > > kernel/trace/trace.h | 17 ++++-- > > > kernel/trace/trace_boot.c | 123 ++++++++++++++++++++++++++++++++++----------- > > > 4 files changed, 144 insertions(+), 59 deletions(-) > > > > applied to tip/tracing/fastboot, thanks Frederic! > > > > one small detail, do we need these messages in the boot tracer: > > > > ##### CPU 1 buffer started #### > > > > they are helpful for latency traces but might be confusing for boot > > traces. (they lose their attraction after having seen a dozen of them) > > Yeah, I was thinking of putting in a iter_ctrl to disable them. But > then, should they be on or off by default? > > The pro for having them off by default, they are not as distracting. > > The con for having them off by default, they lose their meaning, and > developers get confused when they see CPU 1 starting after 100 > prints of CPU0, when they both should have started. i think they are useful to be included for most of the tracers, except the boot tracer (which starts/stop with high frequency). So i'd suggest to keep the default, but also to expose it in an iter_ctl plus dynamically turn it off for the boot tracer. Ingo