Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932268AbWIOVIf (ORCPT ); Fri, 15 Sep 2006 17:08:35 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932269AbWIOVIe (ORCPT ); Fri, 15 Sep 2006 17:08:34 -0400 Received: from e32.co.us.ibm.com ([32.97.110.150]:19855 "EHLO e32.co.us.ibm.com") by vger.kernel.org with ESMTP id S932268AbWIOVId (ORCPT ); Fri, 15 Sep 2006 17:08:33 -0400 Message-ID: <450B164B.7090404@us.ibm.com> Date: Fri, 15 Sep 2006 16:08:27 -0500 From: "Jose R. Santos" Reply-To: jrs@us.ibm.com Organization: IBM User-Agent: Thunderbird 1.5.0.5 (X11/20060728) MIME-Version: 1.0 To: Mathieu Desnoyers CC: Ingo Molnar , Roman Zippel , Andrew Morton , tglx@linutronix.de, karim@opersys.com, Paul Mundt , Jes Sorensen , linux-kernel@vger.kernel.org, Christoph Hellwig , Ingo Molnar , Greg Kroah-Hartman , Tom Zanussi , ltt-dev@shafik.org, Michel Dagenais Subject: Re: [PATCH 0/11] LTTng-core (basic tracing infrastructure) 0.5.108 References: <450AB5F9.8040501@opersys.com> <450AB506.30802@sgi.com> <450AB957.2050206@opersys.com> <20060915142836.GA9288@localhost.usen.ad.jp> <450ABE08.2060107@opersys.com> <1158332447.5724.423.camel@localhost.localdomain> <20060915111644.c857b2cf.akpm@osdl.org> <20060915181907.GB17581@elte.hu> <20060915200559.GB30459@elte.hu> <20060915202233.GA23318@Krystal> In-Reply-To: <20060915202233.GA23318@Krystal> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1392 Lines: 32 Mathieu Desnoyers wrote: > Please Ingo, stop repeating false argument without taking in account people's > corrections : > > * Ingo Molnar (mingo@elte.hu) wrote: > > sorry, but i disagree. There _is_ a solution that is superior in every > > aspect: kprobes + SystemTap. (or any other equivalent dynamic tracer) > > > > I am sorry to have to repeat myself, but this is not true for heavy loads. > This thread has already discuss the merits of static instrumentation when it comes to the performance impacts. The key is now to find a balance between static vs dynamic probes. While it is true that static probes will provide less overhead compared to dynamic probes, some probe point will see less of an impact in measurable performance impact of dynamic probes due to the nature of the probe. We need to find what that balance is. To some people performance is the #1 priority and to other it is flexibility. I would like to come up with a list of those probe point that absolutely need to be inserted into the code statically. Those that are not absolutely critical to have statically should be implemented dynamically. -JRS - 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/