A concurrent architecture for serializable production systems

This paper presents a new production system architecture that takes advantage of modern associative memory devices to allow parallel production firing, concurrent matching, and overlap among matching, selection, and firing of productions. We prove that the results produced by the architecture are correct according to the serializability criterion. A comprehensive event driven simulator is used to evaluate the scaling properties of the new architecture and to compare it with a parallel architecture that does global synchronization before every production firing. We also present measures for the improvement in speed due to the use of associative memories and an estimate for the amount of associative memory needed. Architectural evaluation is facilitated by a new benchmark program that allows for changes in the number of productions, the size of the database, the variance between the sizes of local data clusters, and the ratio between local and global data. Our results indicate that substantial improvements in speed can be achieved with a very modest increase in hardware cost.