Optimization Research Of Real-time Embedded System Scheduling Algorithm Based On Generalized Scheduling Theory

In recent years,with the rapid development of communication electronic technology,the real-time embedded system has been widely used in all aspects of our life.Compared with traditional real-time systems,the resources of embedded real-time systems are limited and its application environment are heterogeneous.Generally,the embedded systems are used in event-driven reactive systems and the task is more difficult to be scheduling.However,current real-time scheduling strategy lead to more preemptions and schedulability of the task-sets is low.It difficult to meet the demands.It has important theoretical significance and practical value for the real-time embedded system,which can reduce switch cost and improve schedulability of the task-sets.This paper mainly studies the problem of task scheduling in the embedded real?time systems.It focuses on different type of the task-set.A scheduling algorithm for synchronous task and a scheduling algorithm for asynchronous real-time task-set are proposed based on the improving generalized scheduling.Lastly,the validity of the algorithms are illustrated by simulation experiments.The main works and research results are as follows:Firstly,schedulability analysis of task was studied in the generalized scheduling.It is found that it only considers the influence of last running stage on response time of task.The task's response time is too long.On the basis of the original generalized scheduling,consider all running stages and reanalyse task's schedulability to reduce task's response time.Using the level-i active period to analyze the task schedulability and deduced determination formula of task schedulability.The determination formula of task schedulability is transformed into a schedulability test based on discontinuation points of cumulative execution-request functions.An assignment algorithm of task's parameters is proposed.It can improve schedulability of the task-sets.Secondly,the task's release exists offset in the embedded real-time systems.An generalized scheduling algorithm for asynchronous task is proposed based on the improving generalized scheduling.The asynchronous task model is established at first.The worst-case response time of asynchronous task is analyzed by feasibility interval of task,and the calculating formula of task's response time is given.On this basis,the paper proposes a scheduling algorithm of asynchronous real-time task-set's parameters and improve the schedulability of asynchronous task-sets.At last,the performance and effectiveness of the proposed algorithms are verified by experiments.Compared with the existing algorithms,the experiment results shows that IFPGS and IFPGS-AST can greatly improve the schedulability of task-set.The algorithms are still a good schedulability when the number of task is large...