TWIN: a parallel scheme for a production system featuring both control and data parallelism

A parallel scheme, called TWIN, for Rete-based production systems is proposed. The TWIN scheme exploits two aspects of the Rete algorithm parallelism: control parallelism in the structural features of the Rete network and data parallelism in token comparison at two-input nodes. TWIN is suited for building a simple, compact, bus-connected parallel system without shared memory or cache memory. An analytical evaluation of the TWIN scheme based on a Rete network model is described. The model can estimate the speed increase in various production system programs without actual execution. The analytical results show that TWIN is superior to the other finer grained schemes when a simple bus-connected processor is adopted. To demonstrate the performance of the TWIN scheme, an experimental measurement using a bus-connected multiprocessor is presented. The results demonstrate that exploiting token comparison parallelism improves performance even for a small production system program