A Skeleton-Based Model for Developing Parallel Applications Using a Network of Processors

  Dhrubajyoti Goswami, Ajit Singh, and Bruno Richard Preiss. manuscript 23 pp., January 1998[5].

One of the greatest obstacles to the mainstream adoption of parallel computing is its complexity. Over the years, various approaches have been proposed to aid parallel program developers. Most of these approaches employ a high-level model of parallel computation, thus hiding the low-level parallelism-related details from the user. Different models employ different abstraction techniques, such as communication libraries, macros, new parallel languages and abstract data types.

In this paper we present a skeleton-based approach which uses frequently occurring structures for parallelism, and is a hybrid of high- and low-level models. Each skeleton is a re-usable, application-independent component providing a commonly used parallel structure. A number of such skeletons can be combined together to create the skeleton of the entire application, which can then be filled in with the application specific components.

Unlike other skeleton-based approaches in the past, this work is unique in the following aspects:

First, it gives a generic definition to a skeleton, with associated structural and behavioral components. The crucial behavioral components were missing in the related works of the past.

Second, it gives a clear-cut and natural model to compose the individual skeletons to develop the entire parallel application. As a result, it is easy for the user to compose skeletons correctly.

Third, unlike the previous approaches, the user can work at various levels of abstraction and also intermix them. For instance, the user can intermix skeletons with the lowest level of communication primitives available to him. This gives him a high degree of flexibility in developing his application.

Fourth, a library-based approach, together with a generic definition of a skeleton, makes it a highly extendible approach, i.e. a new skeleton can be added to the system as per need. Some recent approaches, which intended to be extendible, were in fact hardly extendible due to the absence of a generic viewpoint of a skeleton.

As a direct realization of the model, a library-based development system using object-oriented design methodologies in C++ and the standard Message-Passing Interface (MPI) has been implemented. The latter part of the paper focuses on the implementation and presents experimental results obtained on a cluster of workstations.

Copyright 1998 by D. Goswami, A. Singh and B. R. Preiss.

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