The Study Of Fault-tolerant Real-time Scheduling Algorithm

With the rapid development of electronic technology,the reliability of hardware in real-time system has been greatly increasing,The core scheduling algorithm for real-time software and its reliability have been a bottleneck. The scheduling algorithm is always main research problem in real- time system.Fault-tolerant technology as an important technique for software reliability has become a key issue of real-time systems.The system architecture of embedded systems is introduced firstly, and then he classic real-time scheduling algorithms for static and dynamic real-time scheduling algorithm is introduced.On the base of analyzing the main problem of real-time scheduling algorithm, the fault-tolerant real-time scheduling algorithm is studied deeply.The classical static scheduling algorithm RMS is improved, so that it can handle all types of tasks in complex situations with good real-time characteristic.Combining P/B fault-tolerant technology with the classic static scheduling algorithm, the algorithm can deal periodic and nonperiodic tasks, the system reliability and CPU utilization ratio are raised.The classic dynamic scheduling algorithm EDF is studied , combineing with PFari grouping scheduling algorithm, the multi-processor and tasks are grouped separately. PFari grouping scheduling algorithm is used on the global algorithm, EDF algorithm run on single processor, and combining with the fault-tolerant technology to form PEP algorithm.Through grouping processors,the algorithm reduces the time consumption of PFair algorithm and increases utilization ratio of system resources without reducing the fault-tolerant capability.