Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030287AbWISRoA (ORCPT ); Tue, 19 Sep 2006 13:44:00 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1030393AbWISRoA (ORCPT ); Tue, 19 Sep 2006 13:44:00 -0400 Received: from tomts20.bellnexxia.net ([209.226.175.74]:58822 "EHLO tomts20-srv.bellnexxia.net") by vger.kernel.org with ESMTP id S1030395AbWISRn6 (ORCPT ); Tue, 19 Sep 2006 13:43:58 -0400 Date: Tue, 19 Sep 2006 13:43:57 -0400 From: Mathieu Desnoyers To: Vara Prasad Cc: "Martin J. Bligh" , Ingo Molnar , "Frank Ch. Eigler" , Paul Mundt , linux-kernel , Jes Sorensen , Andrew Morton , Tom Zanussi , Richard J Moore , Michel Dagenais , Christoph Hellwig , Greg Kroah-Hartman , Thomas Gleixner , William Cohen , ltt-dev@shafik.org, systemtap@sources.redhat.com, Alan Cox Subject: Re: [PATCH] Linux Kernel Markers Message-ID: <20060919174357.GB26339@Krystal> References: <20060918234502.GA197@Krystal> <20060919081124.GA30394@elte.hu> <451008AC.6030006@google.com> <45101598.7050309@us.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline In-Reply-To: <45101598.7050309@us.ibm.com> X-Editor: vi X-Info: http://krystal.dyndns.org:8080 X-Operating-System: Linux/2.4.32-grsec (i686) X-Uptime: 13:41:37 up 27 days, 14:50, 4 users, load average: 0.88, 0.37, 0.22 User-Agent: Mutt/1.5.13 (2006-08-11) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1359 Lines: 32 * Vara Prasad (prasadav@us.ibm.com) wrote: > It is an interesting idea but there appears to be following hard issues > (some of which you have already listed) i am not able to see how we can > overcome them > > 1) We are going to have a duplicate of the whole function which means > any significant changes in the original function needs to be done on the > copy as well, you think maintainers would like this double work idea. > Not with my marker proposal. There is only need to compile it with different flags. > 2) Inline functions is often the place where we need a fast path to > overcome the current kprobes overhead. > > 3) As you said it is not trivial across all the platforms to do a switch > to the instrumented function from the original during the execution. > This problem is similar to the issue we are dealing with djprobes. > I would really like to know how good djprobes is at instrumenting the prologue of a function. Mathieu OpenPGP public key: http://krystal.dyndns.org:8080/key/compudj.gpg Key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68 - 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/