Abstract:

Although Linux kernel supports the concept of real-time tasks, it does not provide effective scheduling policies. Besides, as for the classical priority-based scheduling algorithms such as Rate Monotonic （RM） and Earliest Deadline First （EDF） that have been widely applied to real-time systems, priorities are usually determined only by a simple or single factor. Thus, the deadlines of emergency tasks can not be guaranteed and the system resources can not be effectively utilized. In order to solve this problem, this paper proposes a new real-time scheduling algorithm named SBRD （Scheduler Based on RM and EDF）. In this algorithm, the priority is determined by both the importance and the urgency. Experimental results show that SBRD possesses the virtues of both RM and EDF. In SBRD, urgent tasks are given priority in the precondition of guaranteeing important tasks. Thus, the deadlines of more tasks can be guaranteed and the CPU resource can be used more effectively. As compared with the real-time scheduling provided by standard Linux, SBRD is more effective.

Key words: Linux, real-time scheduling algorithm, priority-based scheduling algorithm, deadline