Crosstalk-constrained performance optimization by using wire sizing and perturbation

In this paper, we propose a unified wire sizing and perturbation algorithm for crosstalk-constrained performance optimization that is applicable to general routing structures. Our algorithm is based on a two-stage iterative technique: we first perturb all wires to the positions with the minimum delay, then we adjust the wire sizes to further optimize delay under crosstalk constraints. The unified wire sizing and perturbation technique has the property of unimodality, implying that there is a unique position resulting in the optimal delay and crosstalk. Applying these properties can dramatically reduce the search space and thus lead to a very efficient method to determine the best wire position and the optimal wire size. Experimental results show that our algorithm can achieve average improvements of 44.5% and 40.2% in delay without sacrificing area and crosstalk for the 0.18 /spl mu/m and 0.25 /spl mu/m process technologies, respectively. Further, we develop an effective incremental update technique that can substantially speed up the runtime. Empirically, this technique can reduce runtime by 10 times.