Optimal wire sizing and buffer insertion for low power and a generalized delay model

Abstract

We present efficient, optimal algorithms for timing optimization by discrete wire sizing and buffer insertion. Our algorithms are able to minimize a cost function subject to given timing constraints; we focus on minimization of dynamic power dissipation, but the algorithm is also easily adaptable to, for example, area minimization. In addition, the algorithm efficiently computes the complete, optimal power-delay trade-off curve for added design flexibility. An extension of our basic algorithm accommodates a generalized delay model which takes into account the effect of signal slew on buffer delay which can contribute substantially to overall delay. To the best of our knowledge, our approach represents the first work on buffer insertion to incorporate signal slew into the delay model while guaranteeing optimality. The effectiveness of these methods is demonstrated experimentally.