Runtime Monitoring of Time-sensitive Systems [Tutorial Supplement]

Abstract. This tutorial focuses on issues involved in runtime monitoring of time-sensitive systems, where violation of timing constraints are undesired. Our goal is to describe the challenges in instrumenting, measuring, and monitoring such systems and present our solutions developed in the past few years to deal with these challenges. The tutorial consists of two parts. First, we present challenge problems and corresponding solutions on instrumenting real-time systems so that timing constraints of the system are respected. The second part of the tutorial will focus on time-triggered runtime monitoring, where a monitor is invoked at equal time intervals, allowing designers to schedule regular and monitoring tasks hand-in-hand. Overview of Tutorial In computing systems, correctness refers to the assertion that a system satisfies its specification. Verification is a technique for checking such an assertion and runtime verification refers to a lightweight technique where a monitor checks at run time whether the execution of a system under inspection satisfies or violates a given correctness property. Deploying runtime verification involves instrumenting the program under inspection, so that upon occurrence of events (e.g., value changes of a variable) that may change the truthfulness of a property, the monitor will be called to re-evaluate the property. We call this method event-triggered runtime verification, because each change prompts a reevaluation. Event-triggered runtime verification suffers from two drawbacks: (1) unpredictable overhead, and (2) possible bursts of events at run time. The above defects are undesired in the context of real-time embedded systems, where predictability and timing constraints play a central role. This tutorial focuses on describing our solutions to two challenge problems: -Time-aware instrumentation. Instrumentation is a technique to extract information or trigger events in programs under inspection. Instrumentation is a vital step for enabling system monitoring; i.e. the system is augmented with instructions that invokes a monitor when certain events occur. Instrumentation of software programs while preserving logical correctness is a