Product specifications

5–Using QLogic MPI
QLogic MPI Details
IB6054601-00 H 5-15
A
 In the absence of both the -m option and the MPIHOSTS environment
variable, mpirun uses the file ./mpihosts, if it exists.
 If none of these three methods of specifying the hosts file are used, mpirun
looks for the file ~/.mpihosts.
If you are working in the context of a batch queuing system, it may provide a job
submission script that generates an appropriate mpihosts file.
Using mpirun
The script mpirun is a front end program that starts a parallel MPI job on a set of
nodes in an InfiniPath cluster. mpirun may be run on any i386 or x86_64
machine inside or outside the cluster, as long as it is on a supported Linux
distribution, and has TCP connectivity to all InfiniPath cluster machines to be used
in a job.
The script starts, monitors, and terminates the node programs. mpirun uses ssh
(secure shell) to log in to individual cluster machines, and prints any messages
that the node program prints on stdout or stderr on the terminal from which
mpirun is invoked.
The general syntax is:
$ mpirun [mpirun_options...] program-name [program options]
program-name is usually the pathname to the executable MPI program. When
the MPI program resides in the current directory and the current directory is not in
your search path, then program-name
must begin with ‘./’, for example:
./program-name
Unless you want to run only one instance of the program, use the -np option, for
example:
$ mpirun -np n [other options] program-name
This option spawns n instances of program-name. These instances are called
node programs.
NOTE:
The mpi-frontend-* RPM needs to be installed on all nodes that will be
using mpirun. Alternatively, you can use the mpirun option
-distributed=off, which requires that only the mpi-frontend RPM be
installed on the node where mpirun is invoked. Using -distributed=off
can have a negative impact on mpirun’s performance when running
large-scale jobs. More specifically, this option increases the memory usage
on the host from which mpirun is started and will slow down the job startup,
since it will spawn MPI processes serially.