A general model for performance optimization of sequential systems

Retiming, c-slow retiming and recycling are different transformations for the performance optimization of sequential circuits. For retiming and c-slow retiming, different models that provide exact solutions have already been proposed. An exact model for recycling was yet unknown. This paper presents a general formulation that covers the combination of the three schemes for performance optimization. It provides an exact model based on integer linear programming that resorts to the structural theory of marked graphs. A set of experiments has been designed to show the benefits in performance obtained by combining retiming and recycling. The results also show the applicability of the method in large circuits.