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

Understanding HP-MPI
MPI options
Chapter 3158
c Long message fragment size. If the message is greater
than b, the message is fragmented into pieces up to c in
length (or actual length if less than c) and the
corresponding piece of the user’s buffer is pinned
directly. The default is 4194304 bytes, but on Myrinet
GM and IBAL the default is 1048576 bytes.
MPI_RDMA_NENVELOPE MPI_RDMA_NENVELOPE=N Specifies the number of
short message envelope pairs for each connection if RDMA protocol is
used, where N is the number of envelope pairs. The default is between 8
and 128 depending on the number of ranks.
MPI_RDMA_NFRAGMENT MPI_RDMA_NFRAGMENT=N Specifies the number of
long message fragments that can be concurrently pinned down for each
process, either sending or receiving. The max number of fragments that
can be pinned down for a process is 2*N. The default value of N is 128.
MPI_RDMA_NONESIDED MPI_RDMA_NONESIDED=N Specifies the number of
one-sided operations that can be posted concurrently for each rank, no
matter the destination. The default is 8.
MPI_RDMA_NSRQRECV MPI_RDMA_NSRQRECV=K Specifies the number of
receiving buffers used when the shared receiving queue is used, where K
is the number of receiving buffers. If N is the number of offhost
connection from a rank, then the default value can be calculated as:
The smaller of the values Nx8 and 2048.
In the above example, the number of receiving buffers are calculated as 8
times the number of offhost connections. If this number is greater than
2048, then 2048 is used as the maximum number.
prun/srun environment variables
MPI_SPAWN_PRUNOPTIONS Allows prun options to be implicitly added to
the launch command when SPAWN functionality is used to create new
ranks with prun.
MPI_SPAWN_SRUNOPTIONS Allows srun options to be implicitly added to
the launch command when SPAWN functionality is used to create new
ranks with srun.
MPI_SRUNOPTIONS Allows additional srun options to be specified such as
--label.