[OMPI users] Program hangs when using OpenMPI and CUDA

Hi, I'm confronting a problem when using OpenMPI 1.5.1 on a GPU cluster. My program uses MPI to exchange data between nodes, and uses cudaMemcpyAsync to exchange data between Host and GPU devices within a node. When the MPI message size is less than 1MB, everything works fine. However, when the

[OMPI users] difference between MTL and BTL

Hello all, the FAQ page about using myrinet http://www.open-mpi.org/faq/?category=myrinet says that Note that one cannot use both the mx MTL and the mx BTL components at once. Deciding which to use largely depends on the application being run. Can anybody give any further clue on how to decide