Parallel Programming Guide for HP-UX Systems

MPI
Running
Chapter 2 35
• SIGILL
• SIGBUS
• SIGSEGV
• SIGSYS
In the event one of these signals is not caught by a user signal handler, HP MPI will display a
brief stack trace that can be used to locate the signal in the code.
Signal 10: bus error
PROCEDURE TRACEBACK:
(0) 0x0000489c bar + 0xc [././a.out]
(1) 0x000048c4 foo + 0x1c [,/,/a.out]
(2) 0x000049d4 main + 0xa4 [././a.out]
(3) 0xc013750c _start + 0xa8 [/usr/lib/libc.2]
(4) 0x0003b50 $START$ + 0x1a0 [././a.out]
This feature can be disabled for an individual signal handler by declaring a user-level signal
handler for the signal. To disable for all signals, set the environment variable
MPI_NOBACKTRACE:
% setenv MPI_NOBACKTRACE
MPI_REMSH MPI_REMSH specifies a command other than the default remsh to start remote
processes. The mpirun, mpijob, and mpiclean utilities support MPI_REMSH. For example, you
can set the environment variable to use a secure shell:
% setenv MPI_REMSH /bin/ssh
The alternative remote shell command should be a drop-in replacement for /usr/bin/remsh,
that is, the argument syntax for the alternative shell should be the same as for
/usr/bin/remsh.
MPI_SHMEMCNTL MPI_SHMEMCNTL controls the subdivision of each process’s shared
memory for the purposes of point-to-point and collective communications. The MPI_SHMEMCNTL
syntax is a comma separated list as follows:
nenv , frag , generic
where
nenv Specifies the number of envelopes per process pair. The default is 8.
frag Denotes the size in bytes of the message-passing fragments region. The
default is 87.5 percent of shared memory after mailbox and envelope
allocation.
generic Specifies the size in bytes of the generic-shared memory region. The default
is 12.5 percent of shared memory after mailbox and envelope allocation.