Jeff, I understand what you've said about 32-bit signed INTs, but in my program, the displacement variable that I use for the MPI_GET call is a 64-bit INT (KIND = 8).
In fact, the only thing in my program that isn't a 64-bit INT is the array that I'm trying to transfer values from. I would post my entire test program, but I don't have direct internet access from the machine that I'm working on. Do you need to see the test program? Am I still missing something? Thanks. -----Original Message----- From: users-boun...@open-mpi.org [mailto:users-boun...@open-mpi.org] On Behalf Of Jeff Squyres Sent: Wednesday, July 07, 2010 10:39 AM To: Open MPI Users Subject: EXTERNAL: Re: [OMPI users] MPI_GET beyond 2 GB displacement Sorry for the delay in replying. :-( It's because for a 32 bit signed int, at 2GB, the value turns negative. On Jun 29, 2010, at 1:46 PM, Price, Brian M (N-KCI) wrote: > OpenMPI version: 1.3.3 > > Platform: IBM P5 > > Built OpenMPI 64-bit (i.e., CFLAGS=-q64, CXXFLAGS=-q64, -FFLAGS=-q64, > -FCFLAGS=-q64) > > FORTRAN 90 test program: > - Create a large array (3.6 GB of 32-bit INTs) > - Initialize MPI > - Create a large window to encompass large array (3.6 GB) > - Have PE 0 get 1 32-bit INT from PE1 > o Lock the window > o MPI_GET > o Unlock the window > - Free the window > - Finalize MPI > > Built FORTRAN 90 test program 64-bit using OpenMPI wrapper compiler (mpif90 > -q64). > > Why would this MPI_GET work fine with displacements all the way up to just > under 2 GB, and then fail as soon as the displacement hits 2 GB? > > The MPI_GET succeeds with a displacement of 2147483644 (4 bytes less than 2 > GB). > > I get a segmentation fault (address not mapped) when the displacement is > 2147483648 (2 GB) or larger. > > Thanks. > > _______________________________________________ > users mailing list > us...@open-mpi.org > http://www.open-mpi.org/mailman/listinfo.cgi/users -- Jeff Squyres jsquy...@cisco.com For corporate legal information go to: http://www.cisco.com/web/about/doing_business/legal/cri/ _______________________________________________ users mailing list us...@open-mpi.org http://www.open-mpi.org/mailman/listinfo.cgi/users
