Weak Real-time Task Scheduling Algorithm Based On Urgency In Single-core System

With the rapid development of computers,people have put forward higher requirements on the performance of computers.In addition to faster processing speeds,they also have higher quality of service and require higher reliability of the system.In order to meet people's needs,weak real-time tasks are widely used.Weak real-time tasks are tasks with a certain fault tolerance rate.Many applications of cyber-physical systems including sensing and control will have a certain degree of time fault tolerance.Without affecting the quality of service,a small part of the task execution time is allowed to exceed a certain deadline.Among them,the fault tolerance rate must be limited,otherwise it will lose the significance of real-time tasks.Therefore,it is of great practical and theoretical significance to implement a scheduling strategy based on weak real-time with a higher proportion of scheduling.In the existing weak real-time task scheduling algorithm,the method of setting the threshold and counting the continuous timeout instances cannot accurately reflect the current situation of the task.Now propose a new tensity-based flexible scheduling algorithm FTBS(Flexible Tensity-based scheduler).Under this algorithm,each task instance has its own job level.The job level is calculated by the constraints of the weak real-time task and the running status of the previous job,and the priority is assigned according to the jobs of different levels.The work of the new weak real-time task scheduling algorithm includes:(1)determining the number of job levels of each task according to the parameters of the task model,and determining the level of the next job according to the running status of the job within a certain period of time;(2)Comparison between different job levels and comparison of jobs of the same level to determine the priority of each job.(3)Through a large number of data tests,comparing the schedulable ratio of the FTBS algorithm and the original algorithm,the system can be better analyzed.The new algorithm improves the task decision accuracy of weak real-time systems and improves system performance.Design and propose a new scheduling algorithm,analyze the time complexity of the algorithm,and conduct a large number of simulation experiments under the same conditions.Compared with the original weak real-time scheduling algorithm,urgency-based flexible scheduling algorithm FTBS can achieve a higher proportion of schedulability(average increase of about 40%).