QLogic OFED+ Host Software User Guide, Rev. B
QLogic OFED+ Host Software User Guide, Rev. B
QLogic OFED+ Host Software User Guide, Rev. B
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4–Running <strong>QLogic</strong> MPI on <strong>QLogic</strong> Adapters<br />
<strong>QLogic</strong> MPI and Hybrid MPI/OpenMP Applications<br />
Using MPD<br />
The disadvantage of MPD is reduced security, since it does not use ssh to launch<br />
node programs. It is also more complex to use than mpirun because it requires<br />
starting a ring of MPD daemons on the nodes. Therefore, <strong>QLogic</strong> recommends<br />
using the normal mpirun mechanism for starting jobs, as described in the<br />
previous chapter. However, if you want to use MPD, it is included in the InfiniPath<br />
software.<br />
To start an MPD environment, use the mpdboot program. You must provide<br />
mpdboot with a file that lists the machines that will run the mpd daemon. The<br />
format of this file is the same as for the mpihosts file in the mpirun command.<br />
Here is an example of how to run mpdboot:<br />
$ mpdboot -f hostsfile<br />
After mpdboot has started the MPD daemons, it will print a status message and<br />
drop into a new shell.<br />
To leave the MPD environment, exit from this shell. This will terminate the<br />
daemons.<br />
To use rsh instead of ssh with mpdboot, set the environment variable MPD_RSH<br />
to the pathname of the desired remote shell. For example:<br />
MPD_RSH=‘which rsh‘ mpdboot -n 16 -f hosts<br />
To run an MPI program from within the MPD environment, use the mpirun<br />
command. You do not need to provide an mpihosts file or a count of CPUs; by<br />
default, mpirun uses all nodes and CPUs available within the MPD environment.<br />
To check the status of the MPD daemons, use the mpdping command.<br />
NOTE:<br />
To use MPD, the software package mpi-frontend-*.rpm and python<br />
(available with your distribution) must be installed on all nodes. See the<br />
<strong>QLogic</strong> Fabric <strong>Software</strong> Installation <strong>Guide</strong> for more details on software<br />
installation.<br />
<strong>QLogic</strong> MPI and Hybrid MPI/OpenMP<br />
Applications<br />
<strong>QLogic</strong> MPI supports hybrid MPI/OpenMP applications, provided that MPI<br />
routines are called only by the master OpenMP thread. This application is called<br />
the funneled thread model. Instead of MPI_Init/MPI_INIT (for C/C++ and<br />
Fortran respectively), the program can call<br />
MPI_Init_thread/MPI_INIT_THREAD to determine the level of thread<br />
support, and the value MPI_THREAD_FUNNELED will be returned.<br />
D000046-005 B 4-25
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