Research On Real-time Scheduling Method Based On Tasks With Fixed Preemption Points

Nowadays,real-time systems are more and more widely used in production and life,and they play an important role in fields such as avionics systems and automotive control systems.In order to allocate computing resources more reasonably and efficiently,while satisfying the real-time constraints of real-time systems,the research on real-time system task schedulability analysis algorithms is of great significance.The current schedulability analysis methods of real-time systems based on response time analysis have inadequate response time analysis,low accuracy of the analysis method,large amount of calculation,and imperfect task scheduling model.For example,in the traditional task model,the task is either fully preemptible or completely prohibits preemption.In actual problems,preemption is needed to ensure the execution efficiency of high-priority tasks,but the number of preemptions needs to be limited to reduce the additional overhead caused by preemption.Therefore,it is necessary to study the schedulability method for the new scheduling model.This paper studies the schedulability analysis of real-time tasks with fixed preemption points in real-time multiprocessor systems,respectively under the global fixed priority(G-FP)scheduling algorithm and the global earliest deadline first(G-EDF)scheduling algorithm.Under the G-FP scheduling algorithm,based on the idea of limiting the execution time interval between two consecutive non-preemptable regions,the RTA method is improved to improve the analysis efficiency.Under the G-EDF scheduling algorithm,a new RTA method is proposed.Through a large number of simulation experiments,the results verify the effectiveness of the proposed method.In addition,this paper develops a real-time task schedulability analysis program which can use the method of this paper to analyze the schedulability of tasks with fixed preemption points.