User Manual

HPC FeaturesRev 2.1-1.0.6
Mellanox Technologies
116
These enhancements significantly increase the scalability and performance of message com-
muni-cations in the network, alleviating bottlenecks within the parallel communication libraries
5.1.4 Running SHMEM with Contiguous Pages
Contiguous Pages improves performance by allocating user memory regions over contiguous
pages. It enables a user application to ask low level drivers to allocate contiguous memory for it
as part of
ibv_reg_mr.
 To activate MLNX_OFED 2.0 and the contiguous pages allocator with SHMEM:
Run the following argument to enable compound pages with SHMEM:
If using compound pages is not possible, then the user will fall back to regular hugepages mechanism.
 To force use of compound pages allocator
Run the following command:
For further information on the Contiguous Pages, please refer to Section 4.9, “Contiguous Pages”, on
page 85.
5.1.5 Running ScalableSHMEM Application
The ScalableSHMEM framework contains the shmemrun utility which launches the executable
from a service node to compute nodes. This utility accepts the same command line parameters as
mpirun from the OpenMPI package.
For further information, please refer to OpenMPI MCA parameters documentation at:
http://www.open-mpi.org/faq/?category=running.
Run
"shmemrun --help" to obtain ScalableSHMEM job launcher runtime parameters.
5.2 Message Passing Interface
5.2.1 Overview
Mellanox OFED for Linux includes the following Message Passing Interface (MPI) implementa-
tions over InfiniBand:
• Open MPI 1.4.6 & 1.6.1 – an open source MPI-2 implementation by the Open MPI
Project
• OSU MVAPICH2 1.7 – an MPI-1 implementation by Ohio State University
% /opt/mellanox/openshmem/2.1/bin/shmemrun -mca shmalloc_use_hugepages 5
% /opt/mellanox/openshmem/2.1/bin/shmemrun -mca shmalloc_use_hugepages 5 -x
MR_FORCE_CONTIG_PAGES=1
ScalableSHMEM contains support for environment module system (http://mod-
ules.sf.net/). The modules configuration file can be found at:
/opt/mellanox/openshmem/2.2/etc/shmem_modulefile