Common real-time operating systems rely on priority-based, preemptive scheduling. Resource sharing in such systems potentially leads to priority inversion: processes of high priority can be prevented from entering a critical section and be delayed by processes of lower priority. Since uncontrolled priority inversion can cause high-priority processes to miss their deadlines, a real-time operatin...

We consider a discrete-time cyclic-service system consisting of multiple stations visited by a single server. Customers from several priority classes arrive at an individual station according to independent batch Bernoulli processes. We assume a non-preemptive priority rule and non-zero switch-over times of the server between consecutive stations. 'Ve derive an exact expression for a weighted s...

In this paper we survey the most relevant results for the priority-based schedulability analysis of real-time tasks, both for the fixed and dynamic priority assignment schemes. We give emphasis to the worst-case response time analysis in non-preemptive contexts, which is fundamental for the communication schedulability analysis. We define an architecture to support priority-based scheduling of ...

We consider a single-server priority queue with batch arrivals. We treat the head-of-the-line (HL) or preemptive-resume (PR) priority rule. Assuming that the arrival process of batches is renewal for each priority class and using the point process approach, we express the individual class queue-length distribution in terms of the waiting time and the completion time distributions. Assuming furt...

Priority queueing systems come natural when customers with diversified delay requirements have to wait to get service. The customers that cannot tolerate but small delays get service priority over customers which are less delay-sensitive. In this contribution, we analyze a discretetime two-class preemptive repeat identical priority queue with infinite buffer space and generally distributed serv...

The distributed nature of routing and flow control in a register-insertion ring topology complicates priority enforcement for real-time systems. Two divergent approaches for priority enforcement for ringbased networks are reviewed: a node-oriented scheme called Preemptive Priority Queue and a ring-wide arbitration approach dubbed TRAIN. This paper introduces a hybrid protocol named Directed Flo...

Priority scheduling for packets is a hot topic, as interactive (voice,video) services are being integrated in existing data networks. In this paper, we consider a discrete-time queueing system with a non-preemptive (or Head-Of-the-Line) priority scheduling discipline and a general number of priority classes. Packets of variable length arrive in the queueing system. We derive expressions for the...