Using perturbation tracking to compensate for intrusion in message-passing systems

Execution monitoring plays a central role in most software development tools for parallel and distributed computer systems. However, such monitoring may induce delays that corrupt event timing. If this corruption can be quantified, it may be possible to determine the intrusion-free behavior. In this paper, we describe an algorithm that, given a safe timed Petri net model of the monitored software, can determine the uncorrupted timestamp values, i.e. those that would have been observed had the delays not been present. Monitoring conditions sufficient to ensure correct operation of the algorithm, and examples illustrating the algorithm´s applicability to message-passing systems are also presented. This work is part of a larger effort aimed at identifying cost-effective software alternatives to custom hardware monitoring