Bounding Completion Times of Jobs with Arbitrary Release Times, Variable Execution Times and Resource Sharing

| The workload of many real-time systems can be characterized as a set of preemptable jobs with linear precedence constraints. Typically their execution times are only known to lie within a range of values. In addition jobs share resources and access to the resources must be synchronized to ensure the integrity of the system. This paper is concerned with the schedulability of such jobs when scheduled on a priority-driven basis. It describes three algorithms for computing upper bounds on the completion times of jobs that have arbitrary release times and priorities. The rst two are simple but do not yield suuciently tight bounds, while the last one yields the tightest bounds but has the greatest complexity.