On Sun, Oct 13, 2013 at 09:13:31PM -0500, Jeff Hammond wrote:

I'd like to be able to use MPI_Datatypes to send e.g. 4 GiB messages. Right now, even 2 GiB fails.

Right on, man. My "large count large type" branch has been stuck in review purgatory. Think you are you qualified to review mpich-review/large_count_large_typesize_combo ?

Code is here https://github.com/jeffhammond/HPCGloves/tree/master/examples/mpi64. Test machine is in MCS.

er, maybe I should say "qualified to review, once I pass your tests": % ./test_type_contig.x 15 count = 32768 ocount = 32768 % ./test_type_contig.x 25 count = 33554432 ocount = 33554432 % ./test_type_contig.x 30 count = 1073741824 ocount = 1073741824 % ./test_type_contig.x 31 count = 2147483648 ocount = -2147483648 Heh. silent error vs violent explosion. I'll let you consider which mode is preferable while I go fix my branch. ==rob -- Rob Latham Mathematics and Computer Science Division Argonne National Lab, IL USA