Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964799AbWIQPSp (ORCPT ); Sun, 17 Sep 2006 11:18:45 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S964819AbWIQPSo (ORCPT ); Sun, 17 Sep 2006 11:18:44 -0400 Received: from mx2.mail.elte.hu ([157.181.151.9]:58246 "EHLO mx2.mail.elte.hu") by vger.kernel.org with ESMTP id S964799AbWIQPSn (ORCPT ); Sun, 17 Sep 2006 11:18:43 -0400 Date: Sun, 17 Sep 2006 17:09:53 +0200 From: Ingo Molnar To: Roman Zippel Cc: Paul Mundt , Karim Yaghmour , linux-kernel , Ingo Molnar , Jes Sorensen , Andrew Morton , Tom Zanussi , Richard J Moore , "Frank Ch. Eigler" , Michel Dagenais , Mathieu Desnoyers , Christoph Hellwig , Greg Kroah-Hartman , Thomas Gleixner , William Cohen , "Martin J. Bligh" Subject: Re: tracepoint maintainance models Message-ID: <20060917150953.GB20225@elte.hu> References: <450D182B.9060300@opersys.com> <20060917112128.GA3170@localhost.usen.ad.jp> <20060917143623.GB15534@elte.hu> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4.2.1i X-ELTE-SpamScore: -2.9 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-2.9 required=5.9 tests=ALL_TRUSTED,AWL,BAYES_50 autolearn=no SpamAssassin version=3.0.3 -3.3 ALL_TRUSTED Did not pass through any untrusted hosts 0.5 BAYES_50 BODY: Bayesian spam probability is 40 to 60% [score: 0.4997] -0.1 AWL AWL: From: address is in the auto white-list X-ELTE-VirusStatus: clean Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2024 Lines: 47 * Roman Zippel wrote: > Hi, > > On Sun, 17 Sep 2006, Ingo Molnar wrote: > > > > This thread would be much better off talking about how to go about > > > implementing lightweight markers rather than spent on mindless rants. > > > > i agree, as long as it's lightweight markers for _dynamic tracers_, so > > that we keep our options open - as per the arguments above. > > Could you please explain, why we can't have markers which are usable > by any tracer? the main reason for that i explained in the portion of the email you snipped: > > On the other hand, if we accept static tracers into the mainline > > kernel, we have to decide in favor of tracepoint-maintainance model > > #1 _FOREVER_. It will be a point of no return for a likely long > > time. Moving a static tracepoint or even breaking it will cause > > end-user pain that needs an _upstream kernel fix_. It needs a new > > stable kernel, etc., etc. It is very inflexible, and fundamentally > > so. of course it's easy to have static markup that is usable for both types of tracers - but that is of little use. Static tracers also need the guarantee of a _full set_ of static markups. It is that _guarantee_ of a full set that i'm arguing against primarily. Without that guarantee it's useless to have markups that can be used by static tracers as well: you wont get a full set of tracepoints and the end-user will complain. (partial static markups are of course still very useful to dynamic tracers) ( furthermore, there are other reasons as well: i explained my position in some of those replies that you did not want to "further dvelve into". I'm happy to give you Message-IDs if you'd like to follow up on them, there's no need to repeat them here. ) Ingo - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/