Signal Propagation (HP-UX and Linux only)

HP-MPI supports the propagation of signals from mpirun to application ranks. The mpirun executable traps the following signals and propagates them to the ranks:

SIGINT
SIGTERM
SIGABRT
SIGALRM
SIGFPE
SIGHUP
SIGILL
SIGPIPE
SIGQUIT
SIGSEGV
SIGUSR1
SIGUSR2
SIGBUS
SIGPROF
SIGSYS
SIGTRAP
SIGURG
SIGVTALRM
SIGPOLL
SIGCONT
SIGTSTP

If prun/srun is used for launching the application, then mpirun sends the signal to the responsible launcher and relies on the signal propagation capabilities of the launcher to ensure that the signal is propagated to the ranks. When using prun, SIGTTIN is also intercepted by mpirun, but is not propagated.

When using an appfile, HP-MPI propagates these signals to remote HP-MPI daemons (mpid) and local ranks. Each daemon propagates the signal to the ranks it created. An exception is the treatment of SIGTSTP. When a daemon receives a SIGTSTP signal, it propagates SIGSTOP to the ranks it created and then raises SIGSTOP on itself. This allows all processes related to an HP-MPI execution to be suspended and resumed using SIGTSTP and SIGCONT.

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.