Gang EDF Scheduling of Parallel Task Systems

The preemptive real-time scheduling of sporadic parallel task systems is studied. We present an algorithm, called gang EDF, which applies the earliest deadline first (EDF) policy to the traditional gang scheduling scheme. We also provide schedulability analysis of gang EDF. Specifically, the total amount of interference that is necessary to cause a deadline miss is first identified. The contribution of each task to the interference is then bounded. Finally, verifying that the total amount of contribution does not exceed the necessary interference for every task, the schedulability test is derived. Although the techniques proposed herein are based on the prior results for the sequential task model, we introduce new ideas for the parallel task model.