Characterization of the Space of Feasible Worst-Case Execution Times for Earliest-Deadline-First Scheduling
Characterization of the Space of Feasible Worst-Case Execution Times for Earliest-Deadline-First Scheduling
复制标题
最早截止日期优先调度的可行最坏情况执行时间空间的表征
DOI：
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发表时间：
2009
期刊：
影响因子：
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通讯作者：
J. Hermant
中科院分区：
文献类型：
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作者：
L. George;J. Hermant
本文对按抢占式最早截止日期优先调度策略执行零星任务的实时系统的维数进行了敏感性分析。任务的时效性约束以延迟终止截止日期表示。首先给出了最早期限的新结果，这使我们能够确定可行的最坏情况执行时间空间，表示为c空间，对任何最坏情况执行时间配置都有效。在c空间中，任何具有最坏情况执行时间的任务集都是可行的，以最早的截止日期为优先。我们在第一种方法中证明了c空间域是凸的，这个性质可以用来减少表征c空间域的不等式的数量。我们提出了另一种方法，基于c空间中最坏情况执行时间的最坏情况繁忙周期的概念来减少不等式的数量。此方法可用于满足给定属性的繁忙时段。将这两种方法应用于一个实例，并将最早期限优先调度得到的c空间与期限单调调度得到的c空间进行了比较。
Thispaperpresentsasensitivityanalysisforthedimensioningofreal-timesystemsinwhich sporadic tasks are executed according to the preemptive earliest deadline first scheduling policy. The timeliness constraints of the tasks are expressed in terms of late termination deadlines. New results for earliest deadline first are shown, which enable us to determine the space of feasible worst-case execution times, denoted the C-space, valid for any configuration of worst-case execution times. The C-space is such that any task set with its worst-case execution times in the C-space domain is feasible with earliest deadline first. We show in a first approach that the C-space domain is convex, a property that can be used to reduce the number of inequalities characterizing the C-space domain.We propose in another approach toreducethenumberofinequalitiesbasedontheconceptofworst-casebusyperiodforworstcase execution times in the C-space. This approach can be used for busy periods meeting a given property. We apply the two approaches on an example, and we compare the Cspace obtained with earliest deadline first scheduling to the C-space obtained with deadline monotonic scheduling.