Non-determinate Dependent And-Parallelism Revisited

We consider the problem of exploiting non-determin-istic dependent and-parallelism (DAP) from Prolog programs. The main issues that arise in designing a parallel Prolog system for exploiting DAP are discussed. Three criteria for eecient exploitation of DAP are also developed. These criteria are then used to evaluate and classify existing execution models proposed for exploiting DAP. These criteria also inspire new schemes for exploiting DAP that are arguably better than existing ones. Two such schemes for dependent and-parallelism, termed the Linked Model and the Filter Model are proposed. The Filter model has been incorporated in the ACE and-or parallel Pro-log system running on a Sequent Symmetry and Sun Sparc Multiprocessors. Performance results (on the Symmetry) from this implementation are also presented .