Parallel Programming Guide for HP-UX Systems

MPI
Running
Chapter 246
NOTE Because HP MPI sets up one daemon per host (or appfile entry) for
communication, when you invoke your application with -np x, HP MPI
generates x+1 processes.
Generating multihost instrumentation profiles To generate tracing output files for
multihost applications, you must invoke mpirun on a host where at least one MPI process is
running. HP MPI writes the trace file ( prefix .tr) to the working directory on the host where
mpirun runs.
When you enable instrumentation for multihost runs, and invoke mpirun either on a host
where at least one MPI process is running, or on a host remote from all your MPI processes,
HP MPI writes the instrumentation output file ( prefix .instr) to the working directory on the
host that is running rank 0.
prun It is possible to start applications using the Elan on Linux and Tru64UNIX systems
without mpirun. The following is an example using prun without mpirun:
% prun [ options ] application
This method has restrictions. It does not support MPI-2 dynamic processes or one-sided
communication. We recommend certain environment variables be set before using this
method. They are:
• For Linux:
LD_LIBRARY_PATH=$MPI_ROOT/lib/linux_[ia32|ia64]
Shared libraries will be linked by default. prun will not execute if this is not set.
• For Tru64UNIX:
LD_LIBRARY_PATH=$MPI_ROOT/lib/alpha
Shared libraries will be linked by default. prun will not execute if this is not set.
• For both Linux and Tru64UNIX:
LIBELAN_SHM_ENABLE=0
This tells the Elan system not to allocate its own shared memory. Since we allocate our
own shared memory, the Elan shared memory would be ignored.
NOTE Some versions of Quadrics have a bug that causes multithreaded
applications to hang. Do not set LIBELAN_SHM_ENABLE if you are running
multithreaded applications.