Research On Mixed-Criticality Real-time Scheduling Algorithm Based On Response-time Analysis

In modern safety-critical real-time embedded systems(such as automotive electronic systems,avionics systems),along with the increasing number of applications,the structure of the systems are more and more complex,considering performance,cost savings,functional diversification,safety and reliability,an increasingly important trend of these systems is the integration of components with different levels of criticality onto a common hardware platform.In such a "mixed-criticality" system,different tasks with different criticalities may have interference and influence on each other,which would bring a lot of new challenges and scheduling problems..In the current researches on mixed-criticality system scheduling area,there exist a lot of deficiencies such as deficient algorithm design,inadequate scheduling model.In order to solve these problems,we do researches on the mixed-criticality real-time scheduling algorithm based on response-time analysis.The main research works are as follows:Considering the existing response-time analysis AMC(Adaptive Mixed Criticality)for the tasks with pessimistic period in the mixed-criticality real-time scheduling algorithm are not enough precise and sufficient that it exists the excessive high-criticality tasks' interference on the response time of a task,this paper analyses and introduces the existing response-time analysises for tasks with pessimistic period and makes an improvement on AMC,which reduces the high-criticality tasks' interference on the response time of a task,in order to make it more precise.Based on it we present a sufficient adaptive response-time analysis for mixed-criticality systems(SAMC)considering pessimistic period parameters and MC-OPA(Mixed-Criticality-Optimal Priority Assignment)scheme for fixed-priority uniprocessor scheduling of mixed-criticality system with dual-criticality levels.In the experiments,this paper illustrates the effectiveness of the algorithm by comparing its performance with other algorithms'.Taking into account that the most existing mixed-criticality scheduling algorithms based on response-time analysis for tasks with pessimisitic period only consider the case of dual-criticality systems which can not be suitable to the mixed-criticality system having more than two criticalities,through the detailed analysis of the task's response time in the several criticality levels this paper extends the existing response-time analysis(AMC)and improved response-time analysis(SAMC)for dual-criticality systems to multi-criticality systems in order to make them suitable to multi-criticality systems with pessimisitic period.Then we present two response-time analysis schemes for mixed-criticality systems considering pessimistic period parameters and MC-OPA(Mixed-Criticality-Optimal Priority Assignment)scheme for fixed-priority uniprocessor scheduling of mixed-criticality system with multi-criticality levels.