Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751627AbWIOO7a (ORCPT ); Fri, 15 Sep 2006 10:59:30 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751628AbWIOO7a (ORCPT ); Fri, 15 Sep 2006 10:59:30 -0400 Received: from [81.2.110.250] ([81.2.110.250]:42887 "EHLO lxorguk.ukuu.org.uk") by vger.kernel.org with ESMTP id S1751627AbWIOO73 (ORCPT ); Fri, 15 Sep 2006 10:59:29 -0400 Subject: Re: [PATCH 0/11] LTTng-core (basic tracing infrastructure) 0.5.108 From: Alan Cox To: "Martin J. Bligh" Cc: Paul Mundt , Karim Yaghmour , Jes Sorensen , Roman Zippel , Ingo Molnar , 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 In-Reply-To: <450ABCBB.4090001@mbligh.org> References: <20060914181557.GA22469@elte.hu> <4509A54C.1050905@opersys.com> <450A9EC9.9080307@opersys.com> <20060915132052.GA7843@localhost.usen.ad.jp> <20060915135709.GB8723@localhost.usen.ad.jp> <450AB5F9.8040501@opersys.com> <450AB506.30802@sgi.com> <450AB957.2050206@opersys.com> <20060915142836.GA9288@localhost.usen.ad.jp> <450ABCBB.4090001@mbligh.org> Content-Type: text/plain Content-Transfer-Encoding: 7bit Date: Fri, 15 Sep 2006 16:22:03 +0100 Message-Id: <1158333723.29932.88.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.6.2 (2.6.2-1.fc5.5) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1761 Lines: 41 Ar Gwe, 2006-09-15 am 07:46 -0700, ysgrifennodd Martin J. Bligh: > Moreover, subsystem experts know what needs to be traced in order to > give useful information, and the users may not. It's a damned sight > easier for them to say "oh, please turn on tracing for VM events > and send me the output" than custom-construct a set of probes for > that user, and send them off. There's a barrier to entry that just > won't happen there. That has nothing to do with the static or dynamic probe question. Scriptable dynamic probes do everything your static probes do and more. > Hell, look at all the debug printks in the kernel for example, and > the various small add-hoc tracing facilities. If all we do is unite > those, it'll still be a step forwards. Look how many there are, look how they spread, tracepoints will do the same. > Dynamic probes do NOT reduce maintenance, they increase it. Thats a logical fallacy to begin with. A dynamic probe can probe anything a static probe can. So a static probe can be implemented with a dynamic probe. In other words if you like static probe lists and your subsystem happens to be one where it is useful then you can script it with the same effect and send people the script. With kprobes you've got a passably good chance (ie if Distros can be persuaded to package the debug data) that you can say "run this systemtap script". With static tracepoints its "recompile your vendor kernel in your vendor manner with your vendor initrd and add it to the boot loader" Alan - 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/