Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932164AbWIOSbm (ORCPT ); Fri, 15 Sep 2006 14:31:42 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932158AbWIOSbl (ORCPT ); Fri, 15 Sep 2006 14:31:41 -0400 Received: from mx2.mail.elte.hu ([157.181.151.9]:31124 "EHLO mx2.mail.elte.hu") by vger.kernel.org with ESMTP id S932164AbWIOSbk (ORCPT ); Fri, 15 Sep 2006 14:31:40 -0400 Date: Fri, 15 Sep 2006 20:23:33 +0200 From: Ingo Molnar To: "Frank Ch. Eigler" Cc: Alan Cox , karim@opersys.com, Roman Zippel , Tim Bird , Mathieu Desnoyers , linux-kernel@vger.kernel.org, Christoph Hellwig , Andrew Morton , Ingo Molnar , Greg Kroah-Hartman , Thomas Gleixner , Tom Zanussi , ltt-dev@shafik.org, Michel Dagenais Subject: Re: [PATCH 0/11] LTTng-core (basic tracing infrastructure) 0.5.108 Message-ID: <20060915182333.GA20149@elte.hu> References: <1158323938.29932.23.camel@localhost.localdomain> <1158327696.29932.29.camel@localhost.localdomain> <1158331277.29932.66.camel@localhost.localdomain> <450ABA2A.9060406@opersys.com> <1158332324.29932.82.camel@localhost.localdomain> <1158345108.29932.120.camel@localhost.localdomain> <20060915182428.GI4577@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20060915182428.GI4577@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: 0.5000] -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: 999 Lines: 23 * Frank Ch. Eigler wrote: > > Why are your despatching overheads 1000 cycles ? (and if its due to > > int3 why are you using int 3 8)) > > Smart teams from IBM and Hitachi have been hammering away at this code > for a year or two now, and yet (roughly) here we are. There have been > experiments involving plopping branches instead of int3's at probe > locations, but this is self-modifying code involving multiple > instructions, and appears to be tricky on SMP/preempt boxes. i am talking to them about that, and i'm 100% sure the solution is much easier than the many (much harder) problems that SystemTap has already solved. I think you are way too modest to realize how powerful (and important) SystemTap is :-) 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/