Static probabilistic timing analysis with a permanent fault detection mechanism

Abstract

In recent years, random caches have been proposed as a way to simplify the timing analysis of real-time systems. However, technology-scaling makes caches prone to faults. Fault detection mechanisms can detect permanent faults but they affect the timing analysis of a random cache. This paper introduces a Static Probabilistic Timing Analysis (SPTA) technique that accounts for a permanent fault detection mechanism. The permanent fault detection mechanism periodically checks caches for faults and disables faulty cache blocks to prevent future accesses. The SPTA method operates by periodically switching its runtime between the fault-detection and the no-fault-detection states. This is the first SPTA with a realistic permanent fault detection mechanism. Experiments show that the proposed method always provides safe timing estimations—even when few memory blocks are provided—and accurate results—when sufficient memory blocks are present.