The Dharma scheduler-definitive scheduling in Aurora on multiprocessors architecture

Abstract

In any Or-parallel system which implements the full Prolog language, such as Aurora, there is the problem of processing time being wasted in regions of the search tree which are later pruned away. The author proposes the Dharma scheduler, which introduces a new concept in scheduling for Aurora. Rather than performing scheduling based on the nodes in the search tree, the Dharma scheduler uses the branches of the tree. The author believes that scheduling at this higher level of abstraction has a number of advantages and will make it possible to tackle the problem of wasted speculative work. Early performance results suggest that the Dharma scheduler is faster than any other existing scheduler for Aurora in applications where only the first solution is required. The author presents the design of the Dharma scheduler and performance results.<>