SPRoute 2.0: A detailed-routability-driven deterministic parallel global router with soft capacity

Abstract

Global routing has become more challenging due to advancements in the technology node and the ever-increasing size of chips. Global routing needs to generate routing guides such that (1) routability of detailed routing is considered and (2) the routing is deterministic and fast. In this paper, we firstly introduce soft capacity which reserves routing space for detailed routing based on the pin density and Rectangular Uniform wire Density (RUDY). Second, we propose a deterministic parallelization approach that partitions the netlist into batches and then bulk-synchronously maze-routes a single batch of nets. The advantage of this approach is that it guarantees determinacy without requiring the nets running in parallel to be disjoint, thus guaranteeing scalability. We then design a scheduler that mitigates the load imbalance and livelock issues in this bulk synchronous execution model. We implement SPRoute 2.0 with the proposed methodology. The experimental results show that SPRoute 2.0 generates good quality of results with 43% fewer shorts, 14% fewer DRCs and a 7.4X speedup over a state-of-the-art global router on the ICCAD2019 contest benchmarks.