Lazy Task Creation: A Technique for Increasing the Granularity of Parallel Programs

Many parallel algorithms are naturally expressed at a ne level of granularity, often ner than a MIMD parallel system can exploit eciently. Most builders of parallel systems have looked to either the programmer or a parallelizingcompilerto increase the granularityof such algorithms. In this paper we explore a third approach to the granularity problem by analyzing two strategies for combining parallel tasks dynamically at run-time. Wereject the simplerload-based inlining method, where tasks are combined based on dynamic load level, in favor of the safer and more robust lazy task creation method, where tasks are created only retroactively as processing resources become available. These strategies grew out of work on Mul-T [15], an ecient parallel implementation of Scheme, but could be used with other languages as well. We describe our Mul-T implementationsof lazy task creation for two contrasting machines, and present performance statistics which show the method's eectiveness. Laz...

• Type: Conference
• Year: 1990
• Where: LFP
• Authors: Eric Mohr, David A. Kranz, Robert H. Halstead Jr.
• Keywords: Lazy Task Creation, LFP 1990, Many Parallel Algorithms, Parallel Lisp