A general framework for efficient performance analysis of acyclic asynchronous pipelines

Abstract

Asynchronous design methodologies gain recent extensive attention due to the variability issues in fabricating nanometer integrated circuits. Prior work on asynchronous pipeline performance analysis mostly focused on full buffer pipelines. To date half buffer performance analysis still lacks a systematic and precise treatment. In this paper, we propose a general framework abstracting four-phase asynchronous protocols and thus uniquely enable efficient performance analysis on various acyclic quasi-delay insensitive (QDI) pipelines (including the well-known pre-charged full buffer (PCFB), pre-charged half buffer (PCHB), weak-conditioned half buffer (WCHB), and null convention logic (NCL)) whose analysis has been challenging, if not impossible. Two approaches, linear programming-based performance analysis (LPA) and static performance analysis (SPA), that were applicable only to restricted set of full-buffer and half-buffer pipelines, respectively, are extended to support the entire set of considered pipelines. Thereby the two approaches can be directly compared for the first time. Experiments show that on average SPA achieve five orders of magnitude speedup over LPA, while LPA may provide 7% to 22% tighter cycle time estimation than SPA. Our results are essential to scalable performance analysis for a comprehensive set of QDI circuits.