An O(bn^2) Time Algorithm for Optimal Buffer Insertion with b Buffer Types

Zhuo Li; Weiping Shi

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arXiv · 0710.4691

An O(bn^2) Time Algorithm for Optimal Buffer Insertion with b Buffer Types

Zhuo Li·Weiping Shi

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Abstract

Buffer insertion is a popular technique to reduce the interconnect delay. The classic buffer insertion algorithm of van Ginneken has time complexity O(n^2), where n is the number of buffer positions. Lillis, Cheng and Lin extended van Ginneken's algorithm to allow b buffer types in time O (b^2 n^2). For modern design libraries that contain hundreds of buffers, it is a serious challenge to balance the speed and performance of the buffer insertion algorithm. In this paper, we present a new algorithm that computes the optimal buffer insertion in O (bn^2) time. The reduction is achieved by the observation that the (Q, C) pairs of the candidates that generate the new candidates must form a convex hull. On industrial test cases, the new algorithm is faster than the previous best buffer insertion algorithms by orders of magnitude.

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BibTeX RIS

Zhuo Li, Weiping Shi. 2007-10-25. An O(bn^2) Time Algorithm for Optimal Buffer Insertion with b Buffer Types. https://arxiv.org/abs/0710.4691

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