Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750914AbWIRPvg (ORCPT ); Mon, 18 Sep 2006 11:51:36 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750927AbWIRPvg (ORCPT ); Mon, 18 Sep 2006 11:51:36 -0400 Received: from mx2.mail.elte.hu ([157.181.151.9]:12768 "EHLO mx2.mail.elte.hu") by vger.kernel.org with ESMTP id S1750911AbWIRPve (ORCPT ); Mon, 18 Sep 2006 11:51:34 -0400 Date: Mon, 18 Sep 2006 17:42:56 +0200 From: Ingo Molnar To: "Frank Ch. Eigler" Cc: Alan Cox , Paul Mundt , Mathieu Desnoyers , linux-kernel , Jes Sorensen , Andrew Morton , Tom Zanussi , Richard J Moore , Michel Dagenais , Christoph Hellwig , Greg Kroah-Hartman , Thomas Gleixner , William Cohen , "Martin J. Bligh" Subject: Re: tracepoint maintainance models Message-ID: <20060918154256.GA16448@elte.hu> References: <20060917112128.GA3170@localhost.usen.ad.jp> <20060917143623.GB15534@elte.hu> <20060917153633.GA29987@Krystal> <20060918000703.GA22752@elte.hu> <450DF28E.3050101@opersys.com> <20060918011352.GB30835@elte.hu> <20060918122527.GC3951@redhat.com> <20060918150231.GA8197@elte.hu> <1158594491.6069.125.camel@localhost.localdomain> <20060918154707.GJ3951@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20060918154707.GJ3951@redhat.com> 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: 0.4949] -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: 1278 Lines: 27 * Frank Ch. Eigler wrote: > > I think your implementation is questionable if it causes any kind of > > jumps and conditions, even marked unlikely. Just put the needed data > > in a seperate section which can be used by the debugging tools. > > [...] No need to actually mess with the code for the usual cases. > > Trouble is that it is specifically the *unusual* cases that need > compiler assistance via static markers, otherwise we'd manage with > just k/djprobes & debuginfo type efforts. i think it's all fine as long as it's just a single 5-byte NOP that we are inserting - because in the *usual* case the 'parameter access side-effects' should have no effect. They will have an effect in the *unusual* case though, but that's very much by design - and it's not a performance issue because it's 1) unusual, 2) at most means a bit different code organization by gcc. It very likely wont mean any extra branches even in the unusual case. Or do i underestimate the scope of the problem? ;-) 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/