A Pareto-algebraic framework for signal power optimization in global routing

This paper proposes a framework for (signal) interconnect power optimization at the global routing stage. In a typical design flow, the primary objective of global routing is minimization of wire-length and via consumption. Our framework takes a global routing solution that is optimized for this objective, and quickly generates a new solution that is optimized for signal power, with only a small, controlled degradation in wirelength. Our model of signal power includes layer-dependent fringe and area capacitances of the routes, and their spacing. Our framework is fast compared to the existing global routing procedures, thereby not causing much overhead and fitting well in the design flow to optimize signal power after wire-length minimization. The framework is based on Pareto-algebraic operations and generates multiple global routing solutions to provide a tradeoff between power and wirelength, thereby allowing the user to optimize power with a controlled degradation in wirelength. The generated solution remains free of overflow in routing resource usage. We experiment with large benchmarks from the ISPD 2008 suite and a 45nm technology model. We show on average 19.9% power saving with at most 3% wirelength degradation using the existing wirelength optimized solutions from the open literature.