Extended Device Control Options

Use these options to select a specific fabric combination.

The exact combination of fabrics depends on the number of processes started per node.

If all processes start on one node, the Intel® MPI Library uses shm intra-node communication regardless of the selected option from the list in this topic.

If the number of started processes is less than or equal to the number of available nodes, the library uses the first available fabric from the list of fabrics for inter-node communication.

For other cases, the library uses shm for intra-node communication, and the first available fabric from the list of fabrics for inter-node communication. See I_MPI_FABRICS and I_MPI_FABRICS_LIST for more details.

The shm fabric is available for both Intel® and non-Intel microprocessors, but it may perform additional optimizations for Intel microprocessors than it performs for non-Intel microprocessors.

-rdma

Use this option to select an RDMA-capable network fabric for inter-node communication. The application attempts to use first available RDMA-capable network fabric from the list dapl or ofa. If no such fabric is available, other fabrics from the list tcp or tmi are used. This option is equivalent to the -genv I_MPI_FABRICS_LIST dapl,ofa,tcp,tmi -genv I_MPI_FALLBACK 1 setting.

-RDMA

Use this option to select an RDMA-capable network fabric for inter-node communication. The application attempts to use first available RDMA-capable network fabric from the list dapl or ofa. The application fails if no such fabric is found. This option is equivalent to the -genv I_MPI_FABRICS_LIST dapl,ofa -genv I_MPI_FALLBACK 1 setting.

-dapl

Use this option to select DAPL capable network fabric for inter-node communication. The application attempts to use DAPL capable network fabric. If no such fabric is available, another fabric from the list tcp,tmi or ofa is used. This option is equivalent to the -genv I_MPI_FABRICS_LIST dapl,tcp,tmi,ofa -genv I_MPI_FALLBACK 1 setting.

-DAPL

Use this option to select DAPL capable network fabric for inter-node communication. The application fails if no such fabric is found. This option is equivalent to the -genv I_MPI_FABRICS_LIST dapl -genv I_MPI_FALLBACK 0 setting.

-ib

Use this option to select OFA capable network fabric for inter-node communication. The application attempts to use OFA capable network fabric. If no such fabric is available, another fabric from the list dapl,tcp or tmi is used. This option is equivalent to the -genv I_MPI_FABRICS_LIST ofa,dapl,tcp,tmi -genv I_MPI_FALLBACK 1 setting.

-IB

Use this option to select OFA capable network fabric for inter-node communication. The application fails if no such fabric is found. This option is equivalent to the -genv I_MPI_FABRICS_LIST ofa -genv I_MPI_FALLBACK 0 setting.

-tmi

Use this option to select TMI capable network fabric for inter-node communication. The application attempts to use TMI capable network fabric. If no such fabric is available, another fabric from the list dapl,tcp or ofa is used. This option is equivalent to the -genv I_MPI_FABRICS_LIST tmi,dapl,tcp,ofa -genv I_MPI_FALLBACK 1 setting.

-TMI

Use this option to select TMI capable network fabric for inter-node communication. The application will fail if no such fabric is found. This option is equivalent to the -genv I_MPI_FABRICS_LIST tmi -genv I_MPI_FALLBACK 0 setting.

-mx

Use this option to select Myrinet MX* network fabric for inter-node communication. The application attempts to use Myrinet MX* network fabric. If no such fabric is available, another fabric from the list dapl,tcp or ofa is used. This option is equivalent to the -genv I_MPI_FABRICS_LIST tmi,dapl,tcp,ofa -genv I_MPI_TMI_PROVIDER mx -genv I_MPI_DAPL_PROVIDER mx -genv I_MPI_FALLBACK 1 setting.

-MX

Use this option to select Myrinet MX* network fabric for inter-node communication. The application fails if no such fabric is found. This option is equivalent to the -genv I_MPI_FABRICS_LIST tmi -genv I_MPI_TMI_PROVIDER mx -genv I_MPI_FALLBACK 0 setting.

-psm

Use this option to select Intel® True Scale Fabric for inter-node communication. The application attempts to use Intel True Scale Fabric. If no such fabric is available, another fabric from the list dapl,tcp or ofa is used. This option is equivalent to the -genv I_MPI_FABRICS_LIST tmi,dapl,tcp,ofa -genv I_MPI_TMI_PROVIDER psm -genv I_MPI_FALLBACK 1 setting.

-PSM

Use this option to select Intel True Scale Fabric for inter-node communication. The application fails if no such fabric is found. This option is equivalent to the -genv I_MPI_FABRICS_LIST tmi -genv I_MPI_TMI_PROVIDER psm -genv I_MPI_FALLBACK 0 setting.