This paper compares the performance of three classes of schedulingalgorithms for real-time systems in which jobs may overrun theirallocated processor time potentially causing the system to beoverloaded. The first class, which contains classical priorityscheduling algorithms as exemplified by DM and EDF provides a baseline.The second class is the Overrun Server Method which interrupts theexecution of a job when it has used its allocated processor time andschedules the remaining portion as a request to an aperiodic server. Thefinal class is the Isolation Server Method which executes each job as arequest to an aperiodic server to which it has been assigned. Theperformance of the Overrun Sewer and Isolation Server Methods are worse,in general, than the performance of the baseline algorithms onindependent workloads. However under the dependent workloads considered,the performance of the Isolation Server Method, using a server per taskscheduled according to EDF, was significantly better than theperformance of classical EDF
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