摘要
传统动态调度算法由于对优先级个数没有限制,在实际应用中往往受制约,达不到很好的调度性能。针对此问题,考虑硬实时抢占任务调度需要,提出一种新的组优先级动态实时调度算法。研究作业执行顺序改变对系统可调度性能的影响,给出作业分组可调度性能测试。新算法将满足分组可调度测试公式的作业作为一个任务组,各任务组之间按照最小截止期优先调度,任务组内按照最短作业优先的原则执行作业。仿真结果表明,与最小截止期优先等传统调度算法相比,新算法不仅能有效降低算法所需优先级个数,还能提高任务调度的成功率,缩短平均响应时间,减少任务切换次数。
There is no restriction for priority levels in priority scheduling algorithms, which limits the application in practice to get good schedulability. Aiming at that question, considering the requirement of preemptive scheduling for hard real-time systems, a new group priority dynamic real-time scheduling algorithm was presented. The influence of the changed order for some jobs on the schedulability of the system was studied. The schedulability test for the job grouping was given. In the new algorithm, the jobs that satisfied the formula of the schedulability test were joined together as a group. The jobs outside the group schedule in darliest-deadline-first,while the jobs in the group schedule in shortest job first. The simulation results show that, comparing with the earliest-deadline-first and other traditional scheduling algo- rithms,the priority levels decrease deeply, the success ratio increases, the average response time is shorten and the switching number reduces in the new algorithm.
出处
《计算机科学》
CSCD
北大核心
2009年第7期230-233,239,共5页
Computer Science
关键词
任务调度
最小截止期优先调度算法
成功率
切换次
Task scheduling, Earliest-deadline-first scheduling algorithm, Success ratio, Switching number
