The Study Of Self-Adaptive Fault-Tolerant Scheduling For Real-Time Tasks On Cluster Computing

Owing to excellent extensibility and usability, heterogeneous cluster has gradually become the main platform of current parallel computing. With the growth of real-time applications, more and more computer resources of high computing speed and performance are required. Cluster computing can satisfy the need, because it is good at processing the applications of computing intensity and data intensity. In cluster system, it is key point to improve and optimize the scheduling algorithm for increasing the utilization of system resource. Because the time constraint of the real-time tasks, the scheduling algorithm must incorporate the fault-tolerance technique, for preventing from the task failure under the condition of system faults. Based on the theories of current literatures, this paper studies the fault-tolerance scheduling algorithm for scheduling tasks of service requirement in heterogeneous clusters, to improve the overall performance of the cluster system.The real-time scheduling algorithm of real-time tasks can be done either statically or dynamically. In the static scheduling algorithm, it schedules the tasks whose status is dertermined before the scheduling. In the dynamic scheduling algorithm, it schedules the dynamically arriving tasks whose status is unknown previously. The former can be applied at compiled time and is very efficient, and is mainly used to scheduling periodic tasks with hard deadlines. The latter is more flexible and popular in application. This paper introduces the classical static scheduling algorithm and the extended algorithms. It also introduces the task security requirement model, system reliability model, and system availability model of dynamic scheduling algorithms. Because the fault-tolerance is the essential requirement of real-time scheduling algorithm, this paper presents the application of Primary/Backup fault-tolerance technique in scheduling algorithms.In this paper, my study focuses on dynamic scheduling algorithms. On heterogeneous cluster platform, for dealing with the tasks of special service requirements, such as security requirement and service quality requirement, this paper proposes a flexible self-adaptive fault-tolerance scheduling algorithm, SAOL, using Primary/Backup fault-tolerance technique and considering the time constraint, service requirement, and system performance. The algorithm can adjust the task service level according to the burden of system, enhancing the flexibility and schedulability. Simultaneously, the algorithm incorporates the BB and PB overloading technique, for reducing the redundancy of resource allocation because of the Primary/Backup fault-tolerance technique, improving the resource utilization. At last, the algorithm is compared with an effective scheduling algorithm in the literature through simulation experiments. The experimental results show that the algorithm of SAOL has the superiority with higher performance quality and better flexibility.