MPI Program Debugging and Other Special Option

How to verify which device/provider is used for communication? #mpiexec -np numproc -genv I_MPI_DEBUG 2 $executable    NOTE : genv option to assign a value to the I_MPI_FABRICS (or) I_MPI_DEVICE variable.	Set the I_MPI_DEBUG environment variable to two. The Intel MPI Library will report what device/provider is in use. For example: #mpiexec -np numproc -genv I_MPI_DEBUG 2 $executable
Select Particular Network For Communication Between MPI Process I_MPI_DEVICE =<device>: <provider> Ex 1: I_MPI_DEVICE=rdma:OpenIB-cma0 Ex 2: $ mpirun -n <No of processes>     -env I_MPI_FABRICS shm:dapl <executable>  Note : -genv option to assign a value to the I_MPI_FABRICS variable.	Refer Link : http://software.intel.com/sites/products/documentation/hpc/ics/impi/41/lin/Getting_Started/2_6_Selecting_a_Network_Fabric.htm
Run the test program with all available configurations on your cluster. 1)Test the TCP/IP-capable network fabric using: $ mpirun -n 2 -genv I_MPI_DEBUG 2 -genv I_MPI_FABRICS tcp ./myprog You should see one line of output for each rank, as well as debug output indicating the TCP/IP-capable network fabric is being used. 2)Test the shared-memory and DAPL-capable network fabrics using: $ mpirun -n 2 -genv I_MPI_DEBUG 2 -genv I_MPI_FABRICS shm:dapl ./myprog You should see one line of output for each rank, as well as debug output indicating the shared-memory and DAPL-capable network fabrics are being used.  3)Intel MPI Library selects the most appropriate fabric combination automatically. Set I_MPI_DEVICE =<device>: <provider> For example, I_MPI_DEVICE=rdma:OpenIB-cma0 to select InfiniBand explicitly. Test any other fabric using: $ mpirun -n 2 -genv I_MPI_DEBUG 2 -genv I_MPI_FABRICS <fabric> ./myprog where <fabric> can be a supported fabric. For more information, see Selecting a Network Fabric.

Useful Link: http://software.intel.com/en-us/articles/intel-mpi-library-for-linux-experience-with-various-interconnects-and-dapl-providers

http://software.intel.com/sites/products/documentation/hpc/ics/impi/41/lin/Getting_Started/2_6_Selecting_a_Network_Fabric.htm

MPI NEW COMMANDS

#mpicc -Wall #mpicc -showme:link #mpi

NOTE : #ulimit (set soft limit and hard limit as unlimited to avoid issue).