Monitoring of Real Time Systems by a Separate Processor

Abstract

The use of a separate computer is proposed for implementing a monitoring system for measuring and tracing of real time software systems. This idea combines the flexibility of software monitors with the exactness of hardware monitors: No measurement errors are introduced by the overhead (time and space) of the measurement system itself. Nevertheless high level comfortable measurement facilities are available.An implemented version of this monitoring system, that allows for special investigation of the operating system and task time parameter in a given real time environment is described in detail.The monitoring system provides various facilities: Online display of CPU utilization, histograms of process times, and a survey of operating system times are implemented as standard packages. For special applications PASCAL procedures are available, that yield the relative time since the last checkpoint (usually entry or exit from the operating system). Sample protocols of these monitoring facilities are presented.