Rapid estimation for parameterized components in high-level synthesis

Abstract

An important benefit of high-level synthesis is rapid design space exploration through examination of different design alternatives. However, such design space exploration is not feasible without fast and accurate area and delay estimates of the synthesized designs. These estimates must factor in physical design effects and technology-specific information in order to achieve accuracy. High-level synthesis tools often use abstract, parameterized component generators for describing the synthesized RT design, and thus need to be supported by fast and accurate estimators for these parameterized RT-components. Ideally, one would like to obtain the actual area and delay attributes of each component by constructing (or generating) the designs. However, such constructive methods require excessive run times, prohibiting on-line integration with the tasks of scheduling and allocation. This paper describes a fast (constant-time) method for estimating the area and delay of regular-structured generic RT components that are tuned to a particular technology library. The estimation models are generated using a least-square approximation on a set of sample data points from selected component implementations. The authors performed an extensive set of experiments to validate the estimation technique on combinational as well as sequential RT component generators. The results show a prediction of the area and delay to within 10% of the actual values. These models have also been integrated with a high-level synthesis system to permit on-line estimation of a component's area and delay. >