From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 28766 invoked by alias); 16 Mar 2012 18:17:55 -0000 Received: (qmail 28757 invoked by uid 22791); 16 Mar 2012 18:17:53 -0000 X-SWARE-Spam-Status: No, hits=-6.9 required=5.0 tests=AWL,BAYES_00,RCVD_IN_DNSWL_HI,SPF_HELO_PASS,T_RP_MATCHES_RCVD X-Spam-Check-By: sourceware.org Received: from mx1.redhat.com (HELO mx1.redhat.com) (209.132.183.28) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Fri, 16 Mar 2012 18:17:34 +0000 Received: from int-mx02.intmail.prod.int.phx2.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id q2GIHRgc024884 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Fri, 16 Mar 2012 14:17:33 -0400 Received: from barimba (ovpn01.gateway.prod.ext.phx2.redhat.com [10.5.9.1]) by int-mx02.intmail.prod.int.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id q2GI5fKv029944 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES128-SHA bits=128 verify=NO); Fri, 16 Mar 2012 14:05:42 -0400 From: Tom Tromey To: Mark Kettenis Cc: sergiodj@redhat.com, gdb-patches@sourceware.org Subject: Re: [PATCH 2/3] Implement new features needed for handling SystemTap probes References: <201203101655.q2AGte2M019374@glazunov.sibelius.xs4all.nl> <87wr6pq4s3.fsf@fleche.redhat.com> <201203130858.q2D8w5fe030670@glazunov.sibelius.xs4all.nl> <87ipi5y4qt.fsf@fleche.redhat.com> <201203161452.q2GEq4Q4019189@glazunov.sibelius.xs4all.nl> Date: Fri, 16 Mar 2012 18:17:00 -0000 In-Reply-To: <201203161452.q2GEq4Q4019189@glazunov.sibelius.xs4all.nl> (Mark Kettenis's message of "Fri, 16 Mar 2012 15:52:04 +0100 (CET)") Message-ID: <87haxoqv4a.fsf@fleche.redhat.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.0.94 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org X-SW-Source: 2012-03/txt/msg00627.txt.bz2 >>>>> "Mark" == Mark Kettenis writes: Tom> The static probes in this case are intended to be source- (but not Tom> binary-) compatible with DTrace. Mark> Don't you mean the other way around? As far as I can tell the Mark> SystemTap macros have different names than their DTrace counterparts. Mark> And I'd say that for GDB it's only binary compatibility that really Mark> matters here. No, the SystemTap-provided has compatibility macros with the same names as the DTrace macros. It doesn't try to be binary-compatible. I don't know how the DTrace works at all... Mark> So you are saying that, at least in principle, it should be possible Mark> to use the SystemTap toolchain on any ELF-based system to do Mark> user-space tracing without needing any kernel support? That'd be cool. Nope, just the static markers coming from . The rest of SystemTap is Linux-specific, dynamically creating and loading kernel modules. The probes still have some value outside of SystemTap. With patch #3 in this series, you can use them to better implement "next-over-throw", for C++ debugging. This is because GCC's unwinder has a probe in it that is used by GDB. Tom