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