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
