Selecting Server Parameters for Predictable Runtime Monitoring

Application of runtime monitoring to maintain the health of an embedded real-time software system requires that anomalous behavior be detected within a bounded time while preserving the temporal guarantees of the underlying system. Existing results can compute bounds on the detection latency of runtime monitors that are realized as a deferrable server running at the highest priority. In this paper, we generalize those results to allow monitors to run at an arbitrary priority. We also present an analysis of queue length in predictable runtime monitoring, which allows one to compute an upper bound on queue length. When implementing predictable runtime monitoring, system engineers are presented with several challenges in configuring the parameters of monitor servers. To address those challenges, we explore the tradeoffs among key server parameters and make recommendations about how best to select those parameters to achieve system monitoring objectives.