An Effective Cost-Skew Tradeoff Heuristic for VLSI Global Routing

In global routing of relatively large nets, particularly clock subnets, obtaining a good cost-skew tradeoff has remained beyond the reach of efficient heuristics. This is in contrast to obtaining a good cost-radius tradeoff, which has been well-addressed by a series of methods. We propose a simple heuristic for optimizing the cost-skew tradeoff, based on a "multi-source" variation of the well-known Prim-Dijkstra (PD) construction [1]. Our experiments demonstrate the effectiveness of the multi-source PD heuristic compared to existing alternatives including H-tree [5], bounded-skew DME [10], and original Prim-Dijkstra constructions. We additionally develop characterization data for PD with respect to instance parameters to aid future research.