HP provides an implementation of MPI that runs on all current HP hardware, including the S-class and X-class Exemplar systems [14]. HP MPI was derived from MPICH, but also was significantly influenced by LAM.
HP MPI uses whatever communication medium it has access to: TCP/IP between hosts, shared memory within a host, and a hardware data mover for long messages on Exemplar systems. HP MPI is interoperable among all supported HP systems. HP MPI is well tuned on the high-end systems, with both very low latency and high bandwidth on Exemplar servers. It has also been optimized to use shared memory to implement collective operations where possible, rather than layering on top of point-to-point routines. HP MPI is compliant with MPI 1.2.