From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755142Ab0ETMO5 (ORCPT ); Thu, 20 May 2010 08:14:57 -0400 Received: from mail-ww0-f46.google.com ([74.125.82.46]:34255 "EHLO mail-ww0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754841Ab0ETMOz (ORCPT ); Thu, 20 May 2010 08:14:55 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=date:from:to:cc:subject:message-id:references:mime-version :content-type:content-disposition:in-reply-to:user-agent; b=myAgqmSNBOxwRHXnhsadg32uy+usmS5zK/ioK+jo8zGowpStsW3b3T7BwZ8jlNK0uJ YDTiN+wZYVVhyn1vnAxz71OC7qvbWoRmoCZ8KpjOC1cJQXiK1mLFxkgU9gwXZIP0cR98 D14wNQIhjZfVG5AgzvdGBN4MclBP0r5i2HW3E= Date: Thu, 20 May 2010 14:15:00 +0200 From: Frederic Weisbecker To: Thomas Gleixner Cc: Ingo Molnar , 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: <20100520121458.GF5309@nowhere> 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/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, May 20, 2010 at 01:07:57PM +0200, 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 > > 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. > > Thanks, > > tglx You have a (much) deeper experience than me about the embedded world. And this was the area I worried most about, especially because dropping the preformatted output means we add a random dependency. If you think people can be fine a minimal tool that does this, then ok, as far as the given tool is really easy to get and to build.