HP-MPI Version 2.2 for HP-UX Release Note

HP-MPI V2.2 for HP-UX Release Note

Known Problems and Workarounds

• The way to add to the paths searched by man is to add an entry in /etc/man.config. To

add MPI man pages, add the following line to /etc/man.config:

% MANPATH /opt/mpi/share/man

• Profiling routines built for C calls will no longer cause the corresponding Fortran calls to

be wrapped automatically. In order to profile Fortran routines, separate wrappers need to

be written for the Fortran calls.

• Calling MPI from Fortran 90 programs

HP-MPI complies with the 1.2 version of the MPI standard, which defines bindings for

Fortran 77, but not Fortran 90. Some features of Fortran 90 may interact with MPI

non-blocking semantics to produce unexpected results. Consult the HP MPI User’s Guide

for details.

• Running out of system resources

HP-UX imposes a limit to the number of file descriptors that application processes can

have open at one time. When running an HP-MPI application across multiple hosts, each

local process opens a socket to all remote processes. HP-UX counts these sockets as open

file descriptors, so an HP-MPI application with a large number of off-host processes can

reach the maximum. If your applications frequently exceed the maximum, ask your

system administrator to increase the limit, or use the -commd option with mpirun. Use of

this option results in a run with fewer sockets, but adds a performance penalty for

inter-host communications.

• Locating your instrumentation output file (prefix.instr) when you enable

instrumentation for multi-host runs

Whether you invoke mpirun 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

to the working directory on the host that is running rank 0.

• In order to use the -tv option to mpirun, the TOTALVIEW environment variable must be

set.

% export TOTALVIEW=/opt/totalview/bin/totalview

Or add it to PATH.

• TotalView sometimes displays extra HP-UX threads that have no useful debugging

information.