Jeff, Out of curiosity, did you compile the Fortran test program with -O0 ?
Cheers, Gilles Tom Rosmond <rosm...@reachone.com> wrote: >Jeff, > >Thanks for looking at this. I know it isn't specific to Open-MPI, but it is a >frustrating issue vis-a-vis MPI and Fortran. There are many very large MPI >applications around the world written in Fortran that could benefit greatly >from this MPI-3 capability. My own background is in numerical weather >prediction, and I know it would be welcome in that community. Someone >knowledgeable in both C and Fortran should be able to get to bottom of it. > >T. Rosmond > > > >On 10/25/2016 03:05 PM, Jeff Hammond wrote: > >I can reproduce this with Intel 17 and MPICH on Mac OSX so it's not an >Open-MPI issue. I added VOLATILE to the shared memory objects to prevent >Fortran compiler optimizations as well as a bunch of MPI_Win_sync calls (after >replacing fence with lock_all/unlock_all), but neither changed the outcome. > > >While I claim a modest understanding of MPI-3 RMA and Fortran 2008, >unfortunately, I have never figured out how to use MPI-3 shared memory from >Fortran, which is especially unfortunate since it seems to be a fantastic >source of frustration to both real users such as yourself and MPI+Fortran >standard experts (Rolf). > > >Sorry for the unsatisfying response, but my suspicion is that this is a >program correctness issue. I can't point to any error, but I've ruled out the >obvious alternatives. > > >Jeff > > >On Tue, Oct 25, 2016 at 11:29 AM, Tom Rosmond <rosm...@reachone.com> wrote: > >All: > >I am trying to understand the use of the shared memory features of MPI-3 that >allow direct sharing of the memory space of on-node processes. Attached are 2 >small test programs, one written in C (testmpi3.c), the other F95 >(testmpi3.f90) . They are solving the identical 'halo' exchange problem. >'testmpi3.c' is a simplified version of an example program from a presentation >by Mark Lubin of Intel. I wrote 'testmpi3.f90' to mimic the C version. > > Also attached are 2 text files of the compile, execution, and output of the >respective programs: > >CC_testmpi3.txt >F95_testmpi3.txt > >Note: All 4 files are contained in the attached 'testmpi3.tar.gz'. > >Comparing the outputs of each version, it is clear that the shared memory >copies in 'testmpi3.c' are working correctly, but not in 'testmpi3.f90'. As >far as I can tell, the 2 programs are equivalent up to line 134 of >'testmpi3.c' and lines 97-101 of 'testmpi3.f90'. I thought the calls to >'c_f_pointer' would produce Fortran pointers that would access the correct >shared memory addresses as the C-pointers do in 'testmpi3.c', but clearly that >isn't happening. Can anyone explain why not, and what is needed to make this >happen. Any suggestions are welcome. > >My environment: > Scientific Linux 6.8 > INTEL FORTRAN and ICC version 15.0.2.164 > OPEN-MPI 2.0.1 > > >T. Rosmond > >_______________________________________________ >users mailing list >users@lists.open-mpi.org >https://rfd.newmexicoconsortium.org/mailman/listinfo/users > > > > >-- > >Jeff Hammond >jeff.scie...@gmail.com >http://jeffhammond.github.io/ > > > >_______________________________________________ users mailing list >users@lists.open-mpi.org >https://rfd.newmexicoconsortium.org/mailman/listinfo/users > >
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