Fast and Accurate Routing Demand Estimation for Efficient Routability-driven Placement

This paper presents a fast and accurate routing demand estimation called RUDY and its efficient integration in a force-directed quadratic placer to optimize placements for routability. RUDY is based on a rectangular uniform wire density per net and accurately models the routing demand of a circuit as determined by the wire distribution after final routing. Unlike published routing demand estimation, RUDY depends neither on a bin structure nor on a certain routing model to estimate the behavior of a router. Therefore RUDY is independent of the router. Our fast and robust force-directed quadratic placer is based on a generic demand-and-supply model and is guided by the routing demand estimation RUDY to optimize placements for routability. This yields a placer which simultaneously reduces the routing demand in congested regions and increases the routing supply there. Therefore our placer fully utilizes the potential to optimize the routability. This results in the best published routed wirelength of the IBMv2 benchmark suite until now. In detail, our approach outperforms mPL, ROOSTER, and APlace by 9%, 8%, and 5%, respectively. Compared by the CPU times, which ROOSTER needs to place this benchmark, our routability optimization placer is eight times faster