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[Bug gcov-profile/47618] Collecting multiple profiles and using all for PGO
- From: "roland at rschulz dot eu" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Tue, 24 Jul 2012 23:52:41 +0000
- Subject: [Bug gcov-profile/47618] Collecting multiple profiles and using all for PGO
- Auto-submitted: auto-generated
- References: <bug-47618-4@http.gcc.gnu.org/bugzilla/>
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47618
--- Comment #9 from Roland Schulz <roland at rschulz dot eu> 2012-07-24 23:52:41 UTC ---
I think a tool to merge would be a good partial solution.
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. In
the case of MPI one would want to have the mpi rank as part of the output
folder to guarantee unique file names. Thus my suggestion to support
-fprofile-dir /some/path/%q{SOME_ENV}, where SOME_ENV would be the environment
variable containing the mpi rank. Without being able to make the output path
depending on a environment variable one would be required to write some wrapper
scripts and that might not even be possible in all cases.