Runtime monitoring of timing constraints in distributed real-time systems

Abstract

Embedded real-time systems often operate under strict timing and dependability constraints. To ensure responsiveness, these systems must be able to provide the expected services in a timely manner even in the presence of faults. In this paper, we describe a run-time environment for monitoring of timing constraints in distributed real-time systems. In particular, we focus on the problem of detecting violations of timing assertions in an environment in which the real-time tasks run on multiple processors, and timing constraints can be either inter-processor or intra-processor constraints. Constraint violations are detected at the earliest possible time by deriving and checking intermediate constraints from the user-specified constraints. If the violations must be detected as early as possible, then the problem of minimizing the number of messages to be exchanged between the processors becomes intractable. We characterize a sub-class of timing constraints that occur commonly in distributed real-time systems and whose message requirements can be minimized. We also take into account the drift among the various processor clocks when detecting a violation of a timing assertion. Finally, we describe a prototype implementation of a distributed rim-time monitor.

Runtime Monitoring of Software Execution Trace: Method and Tools

“…A synchronous and asynchronous method proposed in [23] have been described in Section II-B2. To solve the problem of too much time consumption, Jahanian introduced an environment for distributed real-time system runtime monitoring [34]. This method solves several critical issues in the distributed real-time monitoring domain.…”

A Study on Run Time Assurance for Complex Cyber Physical Systems

“…An early application of online monitoring to distributed real-time systems focused on verifying that timing constraints are satisfied; the approach is based on clock-synchronization and timestamps [158]. Many variants of temporal logics have been developed for specifying properties of real-time systems; a survey of these logics is given in Alur and Henzinger [159].…”

Monitoring Time Intervals

“…While we are not aiming at an enforcement scenario, we will rely on a similar technique in the case when events may be delivered from the system to the monitor out of order. Jahanian et al studied the runtime monitoring of time constraints specified by Real-Time Logic (RTL) in the distributed real-time system [5]. However, the monitoring procedure of time intervals was not discussed.…”