Fixed-Priority End-To-End Scheduling in Distributed Real-Time Systems

Abstract

In recent years more and more real-time applications run on multiprocessor or distributed systems. In such systems, a task may execute sequentially on many different processors. Such a task can be viewed as a linear chain of subtasks, each of which represents a segment of the task that executes on one of those processors. The response time of the task is measured from the release of its first subtask to the completion of its last subtask and is called the end-to-end response time. A task is schedulable if its end-to-end response time is never greater than the specified end-to-end relative deadline. This thesis deals with the problem of scheduling periodic tasks to meet their end-to-end deadlines. Specifically, the thesis focuses on fixed-priority scheduling algorithms, where each subtask is assigned a fixed priority and is scheduled preemptively. According to this approach, three related problems need to be solved. Priority Assignment : How we assign the priorities to subtasks so that...