Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751978AbWISTWH (ORCPT ); Tue, 19 Sep 2006 15:22:07 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751979AbWISTWG (ORCPT ); Tue, 19 Sep 2006 15:22:06 -0400 Received: from tomts25.bellnexxia.net ([209.226.175.188]:47591 "EHLO tomts25-srv.bellnexxia.net") by vger.kernel.org with ESMTP id S1751978AbWISTWF (ORCPT ); Tue, 19 Sep 2006 15:22:05 -0400 Date: Tue, 19 Sep 2006 15:16:52 -0400 From: Mathieu Desnoyers To: Vara Prasad Cc: Martin Bligh , prasanna@in.ibm.com, Andrew Morton , "Frank Ch. Eigler" , Ingo Molnar , Paul Mundt , linux-kernel , Jes Sorensen , 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: <20060919191652.GC30556@Krystal> References: <20060918234502.GA197@Krystal> <20060919081124.GA30394@elte.hu> <451008AC.6030006@google.com> <20060919154612.GU3951@redhat.com> <4510151B.5070304@google.com> <20060919093935.4ddcefc3.akpm@osdl.org> <45101DBA.7000901@google.com> <20060919063821.GB23836@in.ibm.com> <45102641.7000101@google.com> <4510413F.2030200@us.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline In-Reply-To: <4510413F.2030200@us.ibm.com> X-Editor: vi X-Info: http://krystal.dyndns.org:8080 X-Operating-System: Linux/2.4.32-grsec (i686) X-Uptime: 15:14:38 up 27 days, 16:23, 6 users, load average: 0.40, 0.23, 0.15 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: 1618 Lines: 34 * Vara Prasad (prasadav@us.ibm.com) wrote: > Martin Bligh wrote: > > >[...] > >Depends what we're trying to fix. I was trying to fix two things: > > > >1. Flexibility - kprobes seem unable to access all local variables etc > >easily, and go anywhere inside the function. Plus keeping low overhead > >for doing things like keeping counters in a function (see previous > >example I mentioned for counting pages in shrink_list). > > > Using tools like systemtap on can consult DWARF information and put > probes in the middle of the function and access local variables as well, > that is not the real problem. The issue here is compiler doesn't seem to > generate required DWARF information in some cases due to optimizations. > The other related problem is when there exists debug information, the > way to specify the breakpoint location is using line number which is not > maintainable, having a marker solves this problem as well. Your proposal > still doesn't solve the need for markers if i understood correctly. > His implementation makes a heavy use of a marker mechanism : this is exactly what permits to create the instrumented objects from the same source code, but with different #defines. 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/