Product specifications

6–Using Other MPIs
Improving Performance of Other MPIs Over IB Verbs
6-12 IB6054601-00 H
S
To compile your program in C using the default compiler, type:
$ mpicc mpi_app_name.c -o mpi_app_name
To use the Intel compiler wrappers (mpiicc, mpiicpc, mpiifort), the Intel
compilers must be installed and resolvable from the user’s environment.
Running Intel MPI Applications
Here is an example of a simple mpirun command running with four processes:
$ mpirun -np 4 -f mpihosts mpi_app_name
For more information, follow the Intel MPI instructions for usage of mpdboot and
mpirun. Remember to use -r ssh with mpdboot if you use ssh. Pass the
following option to mpirun to select uDAPL:
-genv I_MPI_DEVICE rdma:OpenIB-cma
To help with debugging, you can add this option to the Intel mpirun command:
-genv I_MPI_DEBUG 2
Further Information on Intel MPI
For more information on using Intel MPI, see: http://www.intel.com/
Improving Performance of Other MPIs Over IB
Verbs
Performance of MPI applications when using an MPI implementation over IB
Verbs can be improved by tuning the IB MTU size.
mpif77 Fortran 77
mpif90 Fortran 90
mpiicc C (uses Intel C compiler)
mpiicpc C++ (uses Intel C++ compiler)
mpiifort Fortran 77/90 (uses Intel Fortran compiler)
NOTE:
No manual tuning is necessary for PSM-based MPIs, since the PSM layer
determines the largest possible IB MTU for each source/destination path.
Table 6-6. Intel MPI Wrapper Scripts (Continued)
Wrapper Script Name Language