Scheduling Mixed-Criticality Systems to Guarantee Some Service under All Non-erroneous Behaviors
Scheduling Mixed-Criticality Systems to Guarantee Some Service under All Non-erroneous Behaviors
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DOI：
10.1109/ecrts.2016.12
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发表时间：
2016-07
期刊：
影响因子：
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通讯作者：
Sanjoy Baruah;A. Burns;Zhishan Guo
中科院分区：
文献类型：
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作者：
Sanjoy Baruah;A. Burns;Zhishan Guo
在存在相当大的认知不确定性的情况下，必须在部署之前设计和分析许多反应性系统：系统将遇到的外部环境的确切性质以及实施的平台的运行时行为，不能是在部署之前完全确定地预测。混合批判性工作负载的广泛研究的符号模型在估计实时代码的最差执行时间（WCET）时解决了不确定性。对这些WCET值进行了不同级别的保证，不同的估计估计要求所有功能都必须正确执行，如果较不保守的假设成立，则只需要更关键的功能才能正确执行（大概较小的可能性）事件。较不保守的假设无法实现，但更保守的假设确实存在。这里考虑了vestal模型的概括，即使只有更保守的假设，即使较不关键的功能也需要降低（但非零）的服务水平。得出了一种算法，用于调度此更通用模型中指定的双重临界性散发任务系统，该模型在预先性的一级处理器平台上指定，并被证明是速度最佳的。
Many reactive systems must be designed and analyzed prior to deployment in the presence of considerable epistemic uncertainty: the precise nature of the external environment the system will encounter, as well as the run-time behavior of the platform upon which it is implemented, cannot be predicted with complete certainty prior to deployment. The widely-studied Vestal model for mixed-criticality workloads addresses uncertainties in estimating the worst-case execution time (WCET) of real-time code. Different estimations, at different levels of assurance, are made about these WCET values, it is required that all functionalities execute correctly if the less conservative assumptions hold, while only the more critical functionalities are required to execute correctly in the (presumably less likely) event that the less conservative assumptions fail to hold but the more conservative assumptions do. A generalization of the Vestal model is considered here, in which a degraded (but non-zero) level of service is required for the less critical functionalities even in the event of only the more conservative assumptions holding. An algorithm is derived for scheduling dual-criticality implicit-deadline sporadic task systems specified in this more general model upon preemptive uniprocessor platforms, and proved to be speedup-optimal.