MPI SH: a Distributed Shared Memory Implementation of MPI

Most current MP I implementations are developed on top of message passing libraries. This paper considers a rather different approach where MP I primitives are supported through a distributed shared memory. To evaluate this approach, we describe MP I SH, an implementation of MP I on top of DV SA, a package to emulate a shared memory on top of a distributed memory architecture. DV SA structures the shared memory as a set of variable size areas and denes a set of operations each involving a whole area. The various kind of data required to implement MP I, i.e. to handle a communicator, a point to point or a collective communication, can be mapped onto these areas so that a large degree of concurrency, and hence a good performance, can be achieved. Performance gures of MP I SH are presented. Accordingly to these gures, the proposed approach may achieve better performances than more traditional implementations for collective communication.