HP-MPI User's Guide (11th Edition)

Understanding HP-MPI
Signal Propagation (HP-UX and Linux only)
Chapter 3168
The HP-MPI library also changes the default signal handling properties
of the application in a few specific cases. When using the -ha option to
mpirun, SIGPIPE is ignored. When using MPI_FLAGS=U, an MPI signal
handler for printing outstanding message status is established for
SIGUSR1. When using MPI_FLAGS=sa, an MPI signal handler used for
message propagation is established for SIGALRM. When using
MPI_FLAGS=sp, an MPI signal handler used for message propagation is
established for SIGPROF.
In general, HP-MPI relies on applications terminating when they are
sent SIGTERM. Applications which intercept SIGTERM may not
terminate properly.