From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 18178 invoked by alias); 25 Jul 2012 08:25:11 -0000 Received: (qmail 18150 invoked by uid 22791); 25 Jul 2012 08:25:04 -0000 X-SWARE-Spam-Status: No, hits=-4.3 required=5.0 tests=ALL_TRUSTED,AWL,BAYES_00,KHOP_THREADED X-Spam-Check-By: sourceware.org Received: from localhost (HELO gcc.gnu.org) (127.0.0.1) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Wed, 25 Jul 2012 08:24:51 +0000 From: "steven at gcc dot gnu.org" To: gcc-bugs@gcc.gnu.org Subject: [Bug gcov-profile/47618] Collecting multiple profiles and using all for PGO Date: Wed, 25 Jul 2012 08:25:00 -0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: gcc X-Bugzilla-Component: gcov-profile X-Bugzilla-Keywords: X-Bugzilla-Severity: enhancement X-Bugzilla-Who: steven at gcc dot gnu.org X-Bugzilla-Status: NEW X-Bugzilla-Priority: P3 X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org X-Bugzilla-Target-Milestone: --- X-Bugzilla-Changed-Fields: Message-ID: In-Reply-To: References: X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/ Auto-Submitted: auto-generated Content-Type: text/plain; charset="UTF-8" MIME-Version: 1.0 Mailing-List: contact gcc-bugs-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Id: List-Archive: List-Post: List-Help: Sender: gcc-bugs-owner@gcc.gnu.org X-SW-Source: 2012-07/txt/msg01910.txt.bz2 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47618 --- Comment #12 from Steven Bosscher 2012-07-25 08:24:49 UTC --- (In reply to comment #9) > I think a tool to merge would be a good partial solution. We will go with the tool solution. I'll take care of the tool before GCC 4.8, if that's OK with apinski. I think we shouldn't have a new tool, though. I'd prefer to teach the gcov program to do it instead. What would you prefer? > As far as I can see what would still be missing for user-friendly usage, is a > mechanism to guarantee that all pre-merged files are saved with different > names, so that different processes don't overwrite each others output files. Deeply berried in the GCC manuals is this section: http://gcc.gnu.org/onlinedocs/gcc-4.7.1/gcc/Cross_002dprofiling.html With the right combination of GCOV_PREFIX_STRIP and GCOV_PREFIX, it should be possible to send the gcda files to unique directories per MPI rank. But I think that a more practical solution is necessary. (I also don't know how these environment variables interact with -profile-dir. I doubt anyone looked into this before now...) I like the %q (and %p) variables from Valgrind, and I don't think it's very hard to add support for them in libgcov. (http://valgrind.org/docs/manual/manual-core.html)