Simplified Job Startup Command

mpirun 

Syntax

mpirun <options>

where <options> := <mpiexec.hydra options> | [ <mpdboot options> ] <mpiexec options>

Arguments

<mpiexec.hydra options>

mpiexec.hydra options as described in the mpiexec.hydra section. This is the default operation mode. 

<mpdboot options> 

mpdboot options as described in the mpdboot command description, except -n

<mpiexec options> 

mpiexec options as described in the mpiexec section

Description

Use this command to launch an MPI job. The mpirun command uses Hydra* or MPD as the underlying process managers. Hydra is the default process manager. Set the I_MPI_PROCESS_MANAGER environment variable to change the default value.

The mpirun command detects if the MPI job is submitted from within a session allocated using a job scheduler like Torque*, PBS Pro*, LSF*, Parallelnavi* NQS*, SLURM*, Oracle Grid Engine*, or LoadLeveler*. In this case, the mpirun command extracts the host list from the respective environment and uses these nodes automatically according to the above scheme.

In this case, you do not need to create the mpd.hosts file. Allocate the session using a job scheduler installed on your system, and use the mpirun command inside this session to run your MPI job.

Hydra* Specification

When running under a job manager, the mpirun command ignores the -r | --rsh option if Hydra* is used as the underlying process manager. In this case, the corresponding Hydra* bootstrap server is used. Use the bootstrap specific options or corresponding environment variables explicitly to override the auto detected bootstrap server.

The mpirun command silently ignores the MPD specific options for compatibility reasons if you select Hydra* as the active process manager. The following table provides the list of silently ignored and unsupported MPD* options. Avoid these unsupported options if the Hydra* process manager is used.

 

Ignored mpdboot Options 

Ignored mpiexec Options 

Unsupported mpdboot Options 

Unsupported mpiexec Options

--loccons 

-[g]envuser 

--user=<user> | -u <user> 

-a 

--remcons 

-[g]envexcl 

--mpd=<mpdcmd> | -m <mpdcmd> 

 

--ordered |  -o 

-m 

--shell | -s 

 

--maxbranch=<maxbranch> | -b <maxbranch> 

-ifhn <interface/hostname>  

-1 

 

--parallel-startup | -p 

-ecfn <filename> 

--ncpus=<ncpus> 

 

 

-tvsu 

 

 

MPD* Specification

If you select MPD* as the process manager, the mpirun command automatically starts an independent ring of the mpd daemons, launches an MPI job, and shuts down the mpd ring upon job termination.

The first non-mpdboot option (including -n or -np) delimits the mpdboot and the mpiexec options. All options up to this point, excluding the delimiting option, are passed to the mpdboot command. All options from this point on, including the delimiting option, are passed to the mpiexec command.

All configuration files and environment variables applicable to the mpdboot and mpiexec commands also apply to the mpirun command. 

The set of hosts is defined by the following rules, which are executed in this order:

  1. All host names from the mpdboot host file (either mpd.hosts or the file specified by the -f option).

  2. All host names returned by the mpdtrace command, if there is an mpd ring running.

  3. The local host (a warning is issued in this case).

I_MPI_MPIRUN_CLEANUP

Control the environment cleanup after the mpirun command.

Syntax 

I_MPI_MPIRUN_CLEANUP=<value>

Arguments

<value> 

Define the option.

enable | yes | on | 1 

Enable the environment cleanup.

disable | no | off | 0

Disable the environment cleanup. This is the default value.

Description

Use this environment variable to define whether to clean up the environment upon the mpirun completion. The cleanup includes the removal of the eventual stray service process, temporary files, and so on.

I_MPI_PROCESS_MANAGER

Select a process manager to be used by the mpirun command.

Syntax 

I_MPI_PROCESS_MANAGER=<value>

Arguments

<value> 

String value

hydra

Use Hydra* process manager. This is the default value

mpd

Use MPD* process manager 

Description

Set this environment variable to select the process manager to be used by the mpirun command.

Note:

You can run each process manager directly by invoking the mpiexec command for MPD* and the mpiexec.hydra command for Hydra*.