Product specifications

5–Using QLogic MPI
MPD
IB6054601-00 H 5-23
A
The complete list of options is contained in Appendix A.
MPD
The Multi-Purpose Daemon (MPD) is an alternative to mpirun for launching MPI
jobs. It is described briefly in the following sections.
MPD Description
MPD was developed by Argonne National Laboratory (ANL) as part of the
MPICH-2 system. While the ANL MPD had some advantages over the use of their
mpirun (faster launching, better cleanup after crashes, better tolerance of node
failures), the QLogic mpirun offers the same advantages.
The disadvantage of MPD is reduced security, since it does not use ssh to launch
node programs. It is also more complex to use than mpirun because it requires
starting a ring of MPD daemons on the nodes. Therefore, QLogic recommends
using the normal mpirun mechanism for starting jobs, as described in the
previous chapter. However, if you want to use MPD, it is included in the InfiniPath
software.
Using MPD
To start an MPD environment, use the mpdboot program. You must provide
mpdboot with a file that lists the machines on which to run the mpd daemon. The
format of this file is the same as for the mpihosts file in the mpirun command.
Here is an example of how to run mpdboot:
$ mpdboot -f hostsfile
After mpdboot has started the MPD daemons, it will print a status message and
drop into a new shell.
To leave the MPD environment, exit from this shell. This will terminate the
daemons.
To use rsh instead of ssh with mpdboot, set the environment variable MPD_RSH
to the pathname of the desired remote shell. For example:
MPD_RSH=‘which rsh‘ mpdboot -n 16 -f hosts
To run an MPI program from within the MPD environment, use the mpirun
command. You do not need to provide an mpihosts file or a count of CPUs; by
default, mpirun uses all nodes and CPUs available within the MPD environment.
To check the status of the MPD daemons, use the mpdping command.