Empirical Evaluation of Task and Resource Scheduling in Dynamic Real-Time Systems

This paper reports on our on-going empirical evaluation of a two-tiered resource allocation scheme assuming independent jobs, that is, jobs have no precedence constraints. The first tier extends the temporal density approach (load balancing within a time interval), while the second tier uses variations of the Earliest Deadline First (EDF) approach to schedule jobs at a site. However, job scheduling at sites is constrained by the precedence relation between the loading and execution of a job. That is, in addition to CPU scheduling, we also take care of the time it takes to load a task onto memory from a disk (or from another processor over the network). In our scheme, loading (i.e., disk scheduling) uses non-preemptive EDF whereas the execution (i.e., CPU scheduling) uses preemptive EDF. 1 Introduction It is well accepted that there are two classes of realtime systems: hard real-time, in which the violation of the timing properties is a fatal error, and soft realtime in which such a ..