From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 16819 invoked by alias); 7 Jun 2013 20:21:36 -0000 Mailing-List: contact systemtap-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Post: List-Help: , Sender: systemtap-owner@sourceware.org Received: (qmail 16781 invoked by uid 48); 7 Jun 2013 20:21:33 -0000 From: "jistone at redhat dot com" To: systemtap@sourceware.org Subject: [Bug dyninst/14490] Enable stapdyn in multiarch environments Date: Fri, 07 Jun 2013 20:21:00 -0000 X-Bugzilla-Reason: AssignedTo X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: systemtap X-Bugzilla-Component: dyninst X-Bugzilla-Version: unspecified X-Bugzilla-Keywords: X-Bugzilla-Severity: normal X-Bugzilla-Who: jistone at redhat dot com X-Bugzilla-Status: NEW X-Bugzilla-Priority: P2 X-Bugzilla-Assigned-To: systemtap at sourceware dot org X-Bugzilla-Target-Milestone: --- X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: Message-ID: In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-Bugzilla-URL: http://sourceware.org/bugzilla/ Auto-Submitted: auto-generated MIME-Version: 1.0 X-SW-Source: 2013-q2/txt/msg00256.txt.bz2 http://sourceware.org/bugzilla/show_bug.cgi?id=14490 --- Comment #3 from Josh Stone --- If we create a stapdyn32, that means we also have to have dyninst in 32bit. This stapdyn32 also would *only* be capable of probing 32-bit targets. So at this level, I don't see much value in multiarch -- people who know they're targeting 32-bit apps could use an entirely 32-bit stap to begin with. The real value of multiarch IMO comes with mixed targets. Perhaps a 64-bit initial application will fork/exec a 32-bit worker process, etc. All of this monitored with a single stap session. Of course, my opinion now doesn't mesh with my comment #0 about matching archs in stapdyn. We do now dlopen the stap module in stapdyn, and we obviously can't do that for both -m64 and -m32. To make those interoperable, we'll need the same module compiled in both modes, able to talk to the *same* shared memory. So everything in shm would have to be constructed in an arch-neutral fashion. Structs have to be careful about padding, offptr_t has to use a fixed size for its offset, etc. Some parts are mostly just a shared reserve of memory, like the context allocations, so that may not have to completely line up, though a few bits within really are shared. (Dare I throw mixed-endians in there? No, no, that would be crazy...) -- You are receiving this mail because: You are the assignee for the bug.