Nathan E. Doss

A high-performance, portable implementation of the MPI message passing interface standard

MPI (Message Passing Interface) is a specification for a standard library for message passing that was defined by the MPI Forum, a broadly based group of parallel computer vendors, library writers, and applications specialists. Multiple implementations of MPI have been developed. In this paper, we describe MPICH, unique among existing implementations in its design goal of combining portability with high performance. We document its portability and performance and describe the architecture by which these features are simultaneously achieved. We also discuss the set of tools that accompany the free distribution of MPICH, which constitute the beginnings of a portable parallel programming environment. A project of this scope inevitably imparts lessons about parallel computing, the specification being followed, the current hardware and software environment for parallel computing, and project management; we describe those we have learned. Finally, we discuss future developments for MPICH, including those necessary to accommodate extensions to the MPI Standard now being contemplated by the MPI Forum.

Extending the message passing interface (MPI)

MPI is the de facto message passing standard for multicomputers and networks of workstations, established by the MPI Forum, a group of universities, research centers, and national laboratories (from both the United States and Europe), as well as multi-national vendors in the area of high performance computing. MPI has been implemented already by several groups. Worldwide acceptance of MPI has been quite rapid. This paper overviews several areas in which MPI can be extended, discusses the merits of making such extensions, and begins to demonstrate how some of these extensions can be made. In some areas, such as intercommunicator extensions, significant progress has been made by us already. In other areas (such as remote memory access), we are merely proposing extensions to MPI that we have not yet reduced to practice. Furthermore, we point out that other researchers are evidently working in parallel with us on their own extension concepts for MPI.<<ETX>>

The design and evolution of Zipcode

Abstract Zipcode is a message-passing and process-management system that was designed for multicomputers and homogeneous networks of computers in order to support libraries and large-scale multicomputer software. The system has evolved significantly over the last five years, based on our experiences and identified needs. Features of Zipcode that were originally unique to it, were its simulataneous support of static process groups, communication contexts, and virtual topologies, forming the ‘mailer’ data structure. Point-to-point and collective operations reference the underlying group, and use contexts to avoid mixing up messages. Recently, we have added ‘gather-send’ and ‘receive-scatter’ semantics, based on persistent Zipcode ‘invoices’, both as a means to simplify message passing, and as a means to reveal more potential runtime optimizations. Key features in Zipcode appear in the forthcoming MPI standard.