ABSTRACT
This chapter describes the measurement of congestion at all levels of abstraction, from a routed layout up to a multilevel Boolean network. It also describes the postrouting metrics for congestion. The chapter discusses placement-level congestion estimation. It explores congestion metrics at the technology mapping level. The chapter presents whereas those that serve as proxies for congestion during logic synthesis. It reviews several graph theoretic metrics applicable at different stages of the design flow. Constructive congestion maps are created dynamically, employing either probabilistic estimation or fast global routing, during the technology mapping process. The netlength for a mapping solution is computed based on the placement of the subject graph. Some metrics are derived from the placement of the preliminary or final versions of the netlist, whereas others such as mutual contraction and adhesion rely on the structural, graph theoretic properties of the circuit graph.
