iTimerM: A Compact and Accurate Timing Macro Model for Efficient Hierarchical Timing Analysis

Abstract

As designs continue to grow in size and complexity, EDA paradigm shifts from flat to hierarchical timing analysis. In this article, we present compact and accurate timing macro modeling, which is the key to efficient and accurate hierarchical timing analysis. Our goal is to contain only a minimal amount of interface logic in our timing macro model. The main idea is to separate the interface logic into variant and constant timing regions. Then, the variant timing region is reserved for accuracy, while the constant timing region is reduced for compactness. For reducing the constant timing region, we propose anchor pin insertion and deletion by generalizing existing timing graph reduction techniques. Furthermore, we devise a lookup table index selection technique to achieve high model accuracy over the possible operating condition range. Compared with two common models used in industry, extracted timing model and interface logic model, our model has high model accuracy and small model size. Based on the TAU 2016 and 2017 timing macro modeling contest benchmark suites, our results show that our algorithm delivers superior efficiency and accuracy: Hierarchical timing analysis using our model can significantly reduce runtime and memory compared with flat timing analysis on the original design. Moreover, our algorithm outperforms TAU 2016 and 2017 contest winners in model accuracy, model size, model generation performance, and model usage performance.