Design and performance measurements of an execution model for the parallel processing of Prolog programs

This paper presents a hierarchical parallel execution model for Prolog programs, the execution model is based on Or-parallelism/And-parallelism as coarse-grain parallelism, and parallel unification as fine-grain parallelism. At the coarse-grain parallelism level we propose an extended And-Or tree. Consequently, the tree can exploit high degree of parallelism from Prolog programs. Exploiting parallelism of Prolog programs is based an the binding-arrays method for Or-parallelism and the restricted And-parallelism (RAP) method for And-parallelism. At the fine-grain parallelism level, parallel unification is performed. In general, the parallel unification consists of parallel argument matching and consistency checking. However, since the RAP method does not need consistency checking, consistency checking at the fine-grain parallelism level is also removed. The measurements of the parallelism degree of this model are also to be presented in this paper