Clock skew scheduling for timing speculation

By assigning intentional clock arrival times to the sequential elements in a circuit, clock skew scheduling (CSS) techniques can be utilized to improve IC performance. Existing CSS solutions work in a conservative manner that guarantees "always correct" computation, and hence their effectiveness is greatly challenged by the ever-increasing process variation effects. By allowing infrequent timing errors and recovering from them with minor performance impact, timing speculation techniques such as Razor have gained wide interests from both academia and industry. In this work, we formulate the clock skew scheduling problem for circuits equipped with timing speculation capability and propose a novel CSS algorithm based on gradient-descent method. Experimental results on various benchmark circuits demonstrate the effectiveness of our proposed methodology.