Preemptive multi-tasking is a commonly used architecture for designing and implementing embedded real-time software. However, preemptive multi-tasking comes with its own costs. These costs include overheads due to preemptions and context-switches that result in waste of CPU bandwidth. Also, each task incurs a memory cost largely due to the need to maintain a separate stack for each task. These ...

This report considers a sporadic real-time task system with n sporadic tasks on a uniprocessor platform, in which the lowest-priority task is a segmented self-suspension task and the other higher-priority tasks are ordinary sporadic realtime tasks. Under fixed-priority preemptive scheduling, Nelissen et al. in ECRTS 2015 provided a mixed-integer linear programming (MILP) formulation to test whe...

We consider systems with finite sources of requests, multiple servers, and an arbitrary number of preemptive priority classes. The service times and the source idle times are assumed to be exponentially distributed. We present an efficient approach based on marginal state description. The approach allows a recurrent analysis of priority levels where the usage of servers by higher priority reque...

Non-preemptive priority queue system is a type of where customers with higher priorities cannot interrupt low one while being served. High consumers will still be at the head queue. This article discusses non-preemptive multiple working vacations, vacation can interrupted. Customers are classified into two classes, namely class I (non-preemptive customers) and II, exponentially distributed serv...

In this paper, we present a new queueing model providing the accurate average system time for packets transmitted over a cognitive radio (CR) link for multiple traffic classes with the preemptive and non-preemptive priority service disciplines. The analysis considers general packet service time, general distributions for the channel availability periods and service interruption periods, and a s...

This study presents a non-preemptive priority queue model to approximate the cell delay of a multi-channel slotted ring network with a single tunable transmitter and ®xed receiver, and one queue for storing cells for each channel at each node. To analyze network performance, this network is translated to the proposed non-preemptive priority queue model. With this model, the analytical cell-dela...

Due to resource sharing among tasks, priority inversion can occur during prioritydriven preemptive scheduling. In this work, we investigate solutions to the priority inversion problem in a real-time database environment where two-phase locking is employed for concurrency control. We examine two basic schemes for addressing the priority inversion problem, one based on priority inheritance and th...

API extensions and performance improvements to the Linux operating system now enable it to serve as a platform for a range of embedded real-time applications, using fixed-priority preemptive scheduling. Powerful techniques exist for analytical verification of application timing constraints under this scheduling model. However, when the application is layered over an operating system the operati...

Emergency Departments (EDs) operate according to the principle that high-acuity patients should be treated as quickly as possible, ahead of low-acuity patients. Prioritizing treatment for high-acuity patients saves both lives and money, as even small delays in a high-acuity patient’s treatment can negatively affect mortality, recovery times and associated medical costs. In response, many Operat...

This paper studies and gives an analysis of a particular queuing model. It considers a non-preemptive priority queuing system with K ( ≥ 2 ) classes of jobs. The system consists of a single processor. It represents the model of discrete dynamic scheduling problems associated with M k / Gk / 1 / ∞ endogenous priority queues. The processor schedule jobs arriving according to a Markov arrival proc...