A congestion-driven buffer planner with space reservation

In this paper, we present a new algorithm of the four-stage buffer planning to improve success rates of buffer insertion and wiring congestion. It is based on the space reservation, which reserves enough dead space between all adjacent blocks. First of all, we perform the space reservation between all adjacent blocks of an initial floorplan. Second, the shortest path graph is used to select the routing path for each net. Third, the algorithm finds all buffer locations which meet the timing constraints for all nets. Finally, compact the layout to delete the redundant area. Compared to the traditional method, such as channel insertion, our algorithm can reserve enough silicon space for buffer insertion without moving blocks which lead to a large re-computation and area expansion. Experimental results clearly show the superiority of our method to the traditional method without space reservation.