Multi-processor Schedulability Analysis of Preemptive Real-Time Tasks with Variable Execution Times

Abstract

In this paper, we study schedulability analysis problems for multi-processor real-time systems. Assume a set of real-time tasks whose execution times and deadlines are known. We use timed automata to describe the non-deterministic arrival times of tasks. The schedulability problem is to check whether the released task instances can be executed within their given deadlines on a multi-processor platform where each processor has a task queue to buffer task instances scheduled to run on the processor. On the positive side, we show that the problem is decidable for systems with non-preemptive schedulers or tasks with fixed execution times. A surprising negative result is that for multi-processor systems with variable task execution times and a preemptive scheduler, the schedulability analysis problem is undecidable, which is still an open problem in the single-processor setting.KeywordsSchedulability AnalysisRelative DeadlineTask InstanceTask QueueSporadic Task SystemThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.