cient Support for Fine - Grain Parallelism onShared - Memory Machines

A coarse-grain parallel program typically has one thread (task) per processor, whereas a ne-grain program has one thread for each independent unit of work. Although there are several advantages to ne-grain parallelism, conventional wisdom is that coarse-grain parallelism is more eecient. This paper illustrates the advantages of ne-grain parallelism and presents an eecient implementation for shared-memory machines. The approach has been implemented in a portable software package called Filaments, which employs a unique combination of techniques to achieve eeciency. The performance of the ne-grain programs discussed in this paper is always within 13% of a hand-coded coarse-grain program and is usually within 5 percent.