Many existing multiple-processor architectures are designed to efficiently exploit parallelism in a specific narrow range, where the extremes are fine-grained data parallelism and coarse-grained control parallelism. Most real world problems are comprised of multiple tasks which vary in their range of parallelism. Future multiple-processor architectures must be "flexible" in supporting multiple forms of parallelism to tackle these problems. This thesis addresses issues related to communication in "flexible" multiple-processor systems. Intermediate-level vision is chosen as the application domain for demonstrating multi-modal parallelism. The specific problem addressed is to determine the communication requirements of the intermediate level processors of the Image Understanding Architecture, explore the design space of potential solutions, develop a network design that meets the requirements, demonstrate the feasibility of constructing the design, and show both analytically and empirically that the design meets the requirements. The major contributions of this thesis are: (1) Crossbars and other dense networks are viable design alternatives even for large parallel processors; (2) Central control is viable for reasonably large network sizes, which is contrary to conventional wisdom; (3) It is shown that by using a special search memory to implement part of the Clos and Benes network routing algorithm in hardware, it is feasible to quickly reconfigure these networks so that they may be used in fine-grained, data-dependent communication; (4) The feasibility of constructing easily reconfigurable communication networks for "flexible" multiple-processor systems is shown. These networks can quickly reconfigure their topologies to best suit a particular algorithm, can be controlled efficiently (in SIMD as well as MIMD mode), and can efficiently route messages (especially with low overhead in SIMD mode); (5) During the course of this investigation it was discovered that, flexible communication as well as shared memory support is much more critical for supporting intermediate-level vision than providing a variety of fixed communication patterns. This observation may also have implications for general-purpose parallel processing; and (6) It was also discovered that supporting a symbolic token database at the intermediate level is a more fundamental requirement than supporting particular algorithms.
| Identifer | oai:union.ndltd.org:UMASS/oai:scholarworks.umass.edu:dissertations-8286 |
| Date | 01 January 1991 |
| Creators | Rana, Deepak |
| Publisher | ScholarWorks@UMass Amherst |
| Source Sets | University of Massachusetts, Amherst |
| Language | English |
| Detected Language | English |
| Type | text |
| Source | Doctoral Dissertations Available from Proquest |
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