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

Understanding HP-MPI
MPI options
Chapter 3 143
D Dumps shared memory configuration information. Use
this option to get shared memory values that are useful
when you want to set the MPI_SHMEMCNTL flag.
E[on|off] Function parameter error checking is turned off by
default. It can be turned on by setting MPI_FLAGS=Eon.
T Prints the user and system times for each MPI rank.
z Enables zero-buffering mode. Set this flag to convert
MPI_Send and MPI_Rsend calls in your code to
MPI_Ssend, without rewriting your code.
MPI_MT_FLAGS MPI_MT_FLAGS controls runtime options when you use
the thread-compliant version of HP-MPI. The MPI_MT_FLAGS syntax is a
comma separated list as follows:
[ct,][single,][fun,][serial,][mult]
where
ct Creates a hidden communication thread for each rank
in the job. When you enable this option, be careful not
to oversubscribe your system. For example, if you
enable ct for a 16-process application running on a
16-way machine, the result will be a 32-way job.
single Asserts that only one thread executes.
fun Asserts that a process can be multithreaded, but only
the main thread makes MPI calls (that is, all calls are
funneled to the main thread).
serial Asserts that a process can be multithreaded, and
multiple threads can make MPI calls, but calls are
serialized (that is, only one call is made at a time).
mult Asserts that multiple threads can call MPI at any time
with no restrictions.
Setting MPI_MT_FLAGS=ct has the same effect as setting
MPI_FLAGS=s[a][p]#, when the value of # that is greater than 0.
MPI_MT_FLAGS=ct takes priority over the default MPI_FLAGS=sp0
setting. Refer to “MPI_FLAGS” on page 137.