IMA双层调度算法中的任务可调度性分析方法

任务可调度性分析是综合模块化航电(IMA)系统双层调度算法研究中的一个关键问题。针对这个问题,首先剖析了单分区调度系统中任务精确响应时间计算方法所具有的计算复杂度高以及计算函数不连续等局限性;然后提出了一种计算任务响应时间上限的快速方法,分析该计算方法的推导过程,得到了双层调度情况下任务响应时间上限的计算方法,并由此推演出任务可调度性分析方法和分区参数设计方法;最后通过计算机仿真实验,分别使用定量的响应时间上限相对误差法以及定性的资源放大分析法考察了系统任务数量以及系统利用率对文中提出的响应时间上限计算方法精度的影响程度,并得到了该方法取得较高应用精度的可行性条件。

Task schedulability analyzing method of two-level hierarchical scheduling algorithm in integrated modular avionics

The task schedulability analysis on the two-level hierarchical scheduling algorithm in integrated modular avionics(IMA) is a key issue. As for this problem, this paper firstly dissects the method of calculating a task''s exact response time and we learn that this method is limited by its features of high calculating complexity and non-continuity. To overcome these limitations, a method of calculating a task''s upper bound response time is proposed. Further analyzing the method''s deducing process, we achieve the formulation of calculating the response upper bound of a task under two-level hierarchical scheduling. Moreover, a task schedulability analysis method and partition parameters'' designing method are inferred from the formulation. Finally, we deeply investigate how the factors, including the number of all the system tasks and the system utilization, would affect the precision of the upper bound response time calculating method proposed ahead using a quantitative analysis method of upper bound response time relative error and a qualitative analysis method of resource augmentation analyzing respectively. And the practical requirements of obtaining relatively high precision are acquired when applying this method.