Table of Contents

MPI

MPI Version

On VSC-2 several versions of MPI are available. Choose one using 'mpi-selector' or 'mpi-selector-menu':

#list available MPI versions:
$ mpi-selector --list
impi_intel-4.1.0.024
impi_intel-4.1.1.036
intel_mpi_intel64-4.0.3.008
mvapich2_1.8_intel_limic
mvapich2_gcc-1.9a2
mvapich2_intel
openmpi-1.5.4_gcc
openmpi-1.5.4_intel
openmpi_gcc-1.6.4

#see the currently used MPI version:
$ mpi-selector --query
default:impi_intel-4.1.0.024
level:user

#set the MPI version:
$ mpi-selector --set impi_intel-4.1.0.024

Modifications will be active after logging in again.

General recommendations

To make sure that the MPI communication happens via the infiniband fabric, please use the following settings in your job-script and/or in your .bashrc file:

export I_MPI_DAT_LIBRARY=/usr/lib64/libdat2.so.2
export OMP_NUM_THREADS=1
export I_MPI_FABRICS=shm:dapl
export I_MPI_FALLBACK=0
export I_MPI_CPUINFO=proc
export I_MPI_PIN_PROCESSOR_LIST=1,14,9,6,5,10,13,2,3,12,11,4,7,8,15,0
export I_MPI_JOB_FAST_STARTUP=0

Jobs with more than 1024 cores

Jobs with more than 1024 cores