HP-MPI Version 2.2 for Linux Release Note

HP-MPI V2.2 for Linux Release Note

What’s in This Version

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.

MPI_RDMA_NFRAGMENT=N

Specifies the number of long message fragments that can be concurrently pinned down for

each connection. This is only for one-direction traffic. The default is 3.

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_MAX_REMSH=N

This release 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 now 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 variable

MPI_MAX_REMSH. When the number of daemons required is greater than MPI_MAX_REMSH,

mpirun will create only MPI_MAX_REMSH number of remote daemons directly. The directly

created daemons will then create the remaining daemons using an n-ary tree, where n is the

value of MPI_MAX_REMSH. Although this process is generally transparent to the user, the new

startup requires that each node in the cluster is able to use the specified MPI_REMSH command

(e.g. rsh, ssh) to each node in the cluster without a password. The value of MPI_MAX_REMSH is

used on a per-world basis. Therefore, applications which spawn a large number of worlds may

need to use a small value for MPI_MAX_REMSH. MPI_MAX_REMSH is only relevant when using the

-f option to mpirun. The default value is 20.

MPI_VAPI_QPPARAMS=a,b,c,d

Specifies time-out settings for VAPI where:

a Time-out value for VAPI retry if no response from target. Minimum is 1.

Maximum is 31. Default is 18.

b The retry count after time-out before error is issued. Minimum is 0.

Maximum is 7. Default is 7.