Efficient Run-time Monitoring Of Timing Constraints

A real-time system operates under timing constraints which it may be unable to meet under some circumstances. The criticality of a timing constraint determines how a system is to react when a timing failure happens. For critical timing constraints, a timing failure should be detected as soon as possible. However, early detection of timing failures requires more resource usage which may be deemed excessive. While work in real-time system monitoring has progressed in recent years, the issue of tradeoff between detection latency and resource overhead has not been adequately considered. This paper presents an approach for monitoring timing constraints in real-time systems which is based on a simple and expressive specification method for defining the timing constraints to be monitored. Efficient algorithms are developed to catch violations of timing constraints at the earliest possible time. These algorithms have been implemented in a tool called JRTM (Java Run-time Timing-constraint Monitor) in the language Java. This tool can be used to specify and monitor timing constraints of Java applications.