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

Understanding HP-MPI
MPI options
Chapter 3 155
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. The
generic region is typically used for collective
communication.
MPI_SHMEMCNTL=a,b,c where:
a The number of envelopes for shared memory
communication. The default is 8.
b The bytes of shared memory to be used as fragments
for messages.
c The bytes of shared memory for other generic use, such
as MPI_Alloc_mem() call.
MPI_USE_MALLOPT_AVOID_MMAP Instructs the underlying malloc
implementation to avoid mmaps and instead use sbrk() to get all the
memory used. The default is MPI_USE_MALLOPT_AVOID_MMAP=0.
Connection related environment variables
MPI_LOCALIP MPI_LOCALIP specifies the host IP address that is
assigned throughout a session. Ordinarily, mpirun determines the IP
address of the host it is running on by calling gethostbyaddr. However,
when a host uses a SLIP or PPP protocol, the host’s IP address is
dynamically assigned only when the network connection is established.
In this case, gethostbyaddr may not return the correct IP address.
The MPI_LOCALIP syntax is as follows:
xxx.xxx.xxx.xxx
where xxx.xxx.xxx.xxx specifies the host IP address.
MPI_MAX_REMSH MPI_MAX_REMSH=N HP-MPI includes a startup
scalability enhancement when using the -f option to mpirun. This
enhancement allows a large number of HP-MPI daemons (mpid) to be
created without requiring mpirun to maintain a large number of remote
shell connections.
When running with a very large number of nodes, the number of remote
shells normally required to start all of the daemons can exhaust the
available file descriptors. To create the necessary daemons, mpirun uses
the remote shell specified with MPI_REMSH to create up to 20 daemons
only, by default. This number can be changed using the environment