An Effective Algorithm for Buffer Insertion in General Circuits Based on Network Flow

The problem of buffer insertion in a single net has been the focus of most previous research works. However, effective algorithms for buffer insertion in whole circuits are generally needed. In this paper, we relate the timing-constrained minimal buffer insertion problem to the convex cost-flow dual problem and propose an algorithm based on the convex cost-flow theory to solve it in combinational circuits. Experimental results demonstrate that our approach is effective. On the average, for the cases where buffering locations are not specified, our approach achieves a 46% reduction on the total buffer area in comparison to a traditional approach; for the cases where buffering locations are specified, our approach achieves a 52% reduction.