Improved task scheduling algorithm for embedded real-time operating system and its application
Yang Zhang · Journal of Computer Applications · 2009
It is the scheduler that decides the capability of the embedded system.For the Rate-Monotonic(RM)scheduling algorithm determines priority only by the period,the deadline of long period and important tasks can not be guaranteed and the system resources can not be effectively utilized.When the number of the task is infinite,the utilization rate of CPU is only 69%.Here,a new static priority scheduling algorithm called NSRL(new scheduling algorithm based on rate and laxity)was proposed.Two parameters were added to the Task Control Block(TCB):one was the importance of the task,and the other was the laxity.The one whose importance was higher only when its laxity was zero could preempt the running task.The experimental results show that the algorithm can decrease the deadline-missing ratio of the tasks and the CPU resource can be used more effectively.It is an efficient way of scheduling the real-time tasks;also it is useful for the application in wireless broadband and mobile computing.