A novel multithread routing method for FPGAs (abstract only)

Abstract

We propose a platform-independent multithread routing method for FPGAs including two aspects: single high fanout net is routed parallel within itself and several low fanout nets are routed parallel between themselves. Routing for high fanout nets usually takes considerable time because of the large physical area surrounded by bounding boxes to traverse and tens of terminals to connect. Therefore, one high fanout net is partitioned into several subnets with fewer terminals and smaller bounding boxes to be routed in parallel. However, low fanout nets with intrinsic small bounding boxes and few terminals could hardly be divided. Instead, low fanout nets whose bounding boxes are not overlapping with each other are routed concurrently. A new graph, named bounding box graph, was utilized to facilitate the process of selecting several nets to be routed concurrently. In this graph, one vertex stands for a corresponding net and one edge between two connected vertex means that the two represented nets have their bounding boxes overlapped. Several strategies are introduced to balance the load among threads and ensure the deterministic results. The routing times scale down with increasing number of threads. On a 4-core processor, this technique improves the run-time by ~1.9 × with routing quality degrading by no more than 2.3%.