process naming to allow libraries to describe their communication in terms suitable to their own data structures and algorithms, ffl The ability to "adorn" a set of communicating processes with additional user-defined attributes, such as extra collective operations. This mechanism should provide a means for the user or library writer effectively to extend a message-passing notation. In addition, a unified mechanism or object is needed for conveniently denoting communication context, the group of communicating processes, to house abstract process naming, and to store adornments. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 5.1. INTRODUCTION 131 5.1.2 MPI's Support for Libraries The corresponding concepts that MPI provides, specifically to support robust libraries, are as follows: ffl Contexts of communication, ffl Groups of processes, ffl Virtual topologies, ffl Attribute caching, ffl Commun...

We introduce the Split-C language, a parallel extension of C intended for high performance programming on distributed memory multiprocessors, and demonstrate the use of the language in optimizing parallel programs. Split-C provides a global address space with a clear concept of locality and unusual assignment operators. These are used as tools to reduce the frequency and cost of remote access. The language allows a mixture of shared memory, message passing, and data parallel programming styles while providing efficient access to the underlying machine. We demonstrate the basic language concepts using regular and irregular parallel programs and give performance results for various stages of program optimization. 1 Overview Split-C is a parallel extension of the C programming language that supports efficient access to a global address space on current distributed memory multiprocessors. It retains the "small language" character of C and supports careful engineering and optimization of ...

Concurrent Basic Linear Algebra Subprograms (CBLAS) are a sensible approach to extending the successful Basic Linear Algebra Subprograms (BLAS) to multicomputers. We describe many of the issues involved in general-purpose CBLAS. Algorithms for dense matrix-vector and matrix-matrix multiplication on general P \Theta Q logical process grids are presented, and experiments run demonstrating their performance characteristics. This work was supported in part by the Applied Mathematical Sciences subprogram of the Office of Energy Research, U.S. Department of Energy. Work performed under the auspices of the U. S. Department of Energy by the Lawrence Livermore National Laboratory under contract No. W-7405-ENG-48. Submitted to the Concurrency: Practice & Experience. y Address correspondence to: Mississippi State University, Engineering Research Center, PO Box 6176, Mississippi State, MS 39762. 601-325-8435. tony@cs.msstate.edu. Falgout, Skjellum, Smith & Still --- The Multicomputer Toolbo...

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 simultaneous 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. Keywords: Static Process Groups, Contexts, Virtual Topologies, Point-to-Point Communica...

In this paper, we consider what is required to develop parallel algorithms for engineering applications on message-passing concurrent computers (multicomputers). At Caltech, the first author studied the concurrent dynamic simulation of distillation column networks [19, 21, 20, 14]. This research was accomplished with attention to portability, high performance and reusability of the underlying algorithms. Emerging from this work are several key results: first, a methodology for explicit parallelization of algorithms and for the evaluation of parallel algorithms in the distributed-memory context; second, a set of portable, reusable numerical algorithms constituting a "Multicomputer Toolbox," suitable for use on both existing and future medium-grain concurrent computers; third, a working prototype simulation system, Cdyn, for distillation problems, that can be enhanced (with additional work) to address more complex flowsheeting problems in chemical engineering; fourth, ideas for how to a...

Introduction Current Status: No votes Collective communication capabilities are here for MPI-2, covering these areas: ffl Extension of MPI collective operations to intercommunicators ffl Extension of MPI collective operations to in-place buffers. ffl Two-phase collective communication of a limited form and a limited set of operations. ffl A generalized all-to-all collective operation 6.2 Two-phase Collective Communication Current Status: no votes In some applications, better performance can be achieved by separating the initiation and completion of a collective operation. For example, in some numerical applications, better performance can be achieved by overlapping other work (both computation and communication) with an MPI Allreduce. At the same time, the full generality of non-blocking collectiv

The Multicomputer Toolbox is a set of "firstgeneration " scalable parallel libraries. The Toolbox includes sparse, dense, direct and iterative linear algebra, a stiff ODE/DAE solver, and an open software technology for additional numerical algorithms. The Toolbox has an object-oriented design; C-based strategies for classes of distributed data structures (including distributed matrices and vectors) as well as uniform calling interfaces are defined. At a high level in the Toolbox, data-distributionindependence (DDI) support is provided. DDI is needed to build scalable libraries, so that applications do not have to redistribute data before calling libraries. Data-distribution-independent mapping functions implement this capability. Data-distribution-independent algorithms are sometimes more efficient than fixeddata -distribution counterparts, because redistribution of data can be avoided. Underlying the system is a "performance and portability layer," which includes interfaces to sequent...

process naming to allow libraries to describe their communication in terms suitable to their own data structures and algorithms, ffl The ability to "adorn" a set of communicating processes with additional user-defined attributes, such as extra collective operations. This mechanism should provide a means for the user or library writer effectively to extend a message-passing notation. In addition, a unified mechanism or object is needed for conveniently denoting communication context, the group of communicating processes, to house abstract process naming, and to store adornments. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 5.1. INTRODUCTION 131 5.1.2 MPI's Support for Libraries The corresponding concepts that MPI provides, specifically to support robust libraries, are as follows: ffl Contexts of communication, ffl Groups of processes, ffl Virtual topologies, ffl Attribute caching, ffl Commun...

process naming to allow libraries to describe their communication in terms suitable to their own data structures and algorithms, ffl The ability to "adorn" a set of communicating processes with additional user-defined attributes, such as extra collective operations. This mechanism should provide a means for the user or library writer effectively to extend a message-passing notation. In addition, a unified mechanism or object is needed for conveniently denoting communication context, the group of communicating processes, to house abstract process naming, and to store adornments. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 134 CHAPTER 5. GROUPS, CONTEXTS, AND COMMUNICATORS 5.1.2 MPI's Support for Libraries The corresponding concepts that MPI provides, specifically to support robust libraries, are as follows: ffl Contexts of communication, ffl Groups of processes, ffl Virtual topolo...