Research on Real-time Performance of Aperiodic Task for Fixed Priority Preemptive Scheduling Algorithm
Qin Wang, Lingling Yuan, Yan Zhang · Journal of Chinese Computer Systems · 2011
Embedded real-time system should not only meet the functional requirements,but also meet the real-time requirements.Given the scheduling algorithm,the real-time performance depends on the arrival characteristics and execution time of each task.Application environment determines the characteristics of the task arrival.Therefore,this paper studies the effect of the task execution time on the real-time performance so as to provide some references for the embedded system design.For fixed priority preemptive scheduling algorithm,we apply queuing theory,and propose a theoretical model of aperiodic real-time tasks.The theoretical model contains two aperiodic real-time tasks whose priorities are different,and we give the effect of the task execution time length on real-time performance,which contains the deadline miss ratio,the task response time and the task queue length.This paper gives an application example,and the simulation results verify that the theoretical model is correct.