Enabling TDMA Arbitration in the Context of MBPTA

Abstract

Current timing analysis techniques can be broadly classified into two families: deterministic timing analysis (DTA) and probabilistic timing analysis (PTA). Each family defines a set of properties to be provided (enforced) by the hardware and software platform so that valid Worst-Case Execution Time (WCET) estimates can be derived for programs running on that platform. However, the fact that each family relies on each own set of hardware designs limits their applicability and reduces the chances of those designs being adopted by hardware vendors. In this paper we show that Time Division Multiple Access (TDMA), one of the main DTA-compliant arbitration policies, can be made PTA-compliant. To that end, we analyze TDMA in the context of measurement-based PTA (MBPTA) and show that padding execution time observations conveniently leads to trustworthy and tight WCET estimates with MBPTA without introducing any hardware change. In fact, TDMA outperforms round-robin and time-randomized policies in terms of WCET in the context of MBPTA.