From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755042Ab0ETLnI (ORCPT ); Thu, 20 May 2010 07:43:08 -0400 Received: from mx3.mail.elte.hu ([157.181.1.138]:50201 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753347Ab0ETLnF (ORCPT ); Thu, 20 May 2010 07:43:05 -0400 Date: Thu, 20 May 2010 13:42:18 +0200 From: Ingo Molnar To: Thomas Gleixner Cc: Frederic Weisbecker , Steven Rostedt , LKML , Linus Torvalds , Andrew Morton , Peter Zijlstra , Christoph Hellwig , Mathieu Desnoyers , Li Zefan , Lai Jiangshan , Johannes Berg , Masami Hiramatsu , Arnaldo Carvalho de Melo , Tom Zanussi , KOSAKI Motohiro , Andi Kleen , Masami Hiramatsu , Lin Ming , Cyrill Gorcunov , Mike Galbraith , Paul Mackerras , Hitoshi Mitake , Robert Richter Subject: Re: [RFD] Future tracing/instrumentation directions Message-ID: <20100520114218.GA15531@elte.hu> References: <1274291514.26328.930.camel@gandalf.stny.rr.com> <20100520093131.GA30929@elte.hu> <20100520100732.GD5309@nowhere> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.20 (2009-08-17) X-ELTE-SpamScore: -2.0 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-2.0 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.5 -2.0 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 * Thomas Gleixner wrote: > On Thu, 20 May 2010, Frederic Weisbecker wrote: > > On Thu, May 20, 2010 at 11:31:31AM +0200, Ingo Molnar wrote: > > > - [ While it's still a long way off, if this trend continues > > > we eventually might even be able to get rid of the > > > /debug/tracing/ temporary debug API and get rid of > > > the ugly in-kernel pretty-printing bits. This is > > > good: it may make Andrew very happy for a change ;-) > > > > > > The main detail here to be careful of is that lots of > > > people are fond of the simplicity of the > > > /debug/tracing/ debug UI, so when we replace it we > > > want to do it by keeping that simple workflow (or > > > best by making it even simpler). I have a few ideas > > > how to do this. > > > > How? We can emulate the /debug/tracing result with something > > like perf trace, still that won't replace the immediate > > availability of the result of any trace, which makes it > > valuable for any simplest workflows. > > I'm a bit torn about this. I really like the availability of the ascii > interface, but if we can come up with a very basic trace binary tool > which can be built for deep embedded w/o requiring the world and some > more libs to be available, then I might give up my resistance. Ideally > it should be done so it can be easily integrated into busybox. > > I don't care whether I do > > echo 1 >/debug/..../XXX/enable > cat /debug/tracing/trace > > or > > perfmini trace enable XXX > perfmini trace dump My suggestion for that flow is even shorter: trace --enable XXX trace Plus: trace --list trace --enable trace --disable > as long as the tool is built in a way that it does not > need updates when we add trace points or other > functionality to the kernel. Yeah, most definitely. The sysfs event_source class will ensure that whatever (new) events are available propagate through the tool and are available to it. Thanks, Ingo