Implementation and evaluation of dynamic predicates on the sequential inference machine CHI

Abstract

The dynamic clause compilation technique which is used to implement Prolog's dynamic predicates is described. The effectiveness of the technique when applied to a practical application program executed on the sequential inference machine CHI is reported. Dynamic predicates are indispensable in writing practical Prolog application programs. According to the authors' application program analysis, many applications spend more than half of the total execution time in dynamic predicate execution. This means that speeding up dynamic predicates is essential for improving Prolog application performance. From this point of view, the authors introduced the dynamic clause compilation technique, and implemented it on CHI. As soon as a clause is added to Prolog's database, the clause is compiled into machine instructions. This technique greatly accelerates dynamic predicate execution. Application program analysis shows that dynamic clause compilation accelerates the application execution speed up to 5 times faster than conventional dynamic predicate implementation.<>