Buffer library selection

Abstract

Buffer insertion has become a critical optimization technique in high performance design. Perhaps the most prevalent buffer insertion technique is Van Ginneken's dynamic programming algorithm. Although very effective, the algorithm has time complexity that is quadratic in terms of the input buffer library size. Consequently, to achieve an efficient algorithm, it is critical that the buffer library used by the tool be relatively small, containing a subset of the most effective buffers. We propose a new algorithm for selecting a buffer library from all the buffers available in the technology, thereby permitting efficient buffer insertion. We show that the smaller buffer libraries constructed by our algorithm result in little loss in solution quality while speeding up the buffer insertion algorithm by orders of magnitude.