Many existing studies on mixed-criticality (MC) scheduling assume that low-criticality budgets for high-criticality applications are known apriori. These budgets are primarily used as guidance to determine when the scheduler should switch the system mode from low to high. Based on this key observation, in this paper we propose a dynamic MC scheduling model under which low-criticality budgets for individual high-criticality applications are determined at runtime as opposed to being fixed offline. To ensure sufficient budget for high-criticality applications at all times, we use offline schedulability analysis to determine a system-wide total low-criticality budget allocation for all the high-criticality applications combined. This total budget is used as guidance in our model to determine the need for a mode-switch. The runtime strategy then distributes this total budget among the various applications depending on their execution requirement and with the objective of postponing mode-switch as much as possible. We show that this runtime strategy is able to postpone mode-switches for a longer time than any strategy that uses a fixed low-criticality budget allocation for each application. Finally, since we are able to control the total budget allocation for high-criticality applications before mode-switch, we also propose techniques to determine these budgets considering system-wide objectives such as schedulability and service guarantee for low-criticality applications.

中文翻译：

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具有混合临界系统服务保证的动态预算管理

许多现有的关于混合临界 (MC) 调度的研究假设高临界应用的低临界预算是先验已知的。这些预算主要用作确定调度程序何时应将系统模式从低切换到高的指导。基于这一关键观察，在本文中，我们提出了一种动态 MC 调度模型，在该模型下，各个高关键应用程序的低关键预算是在运行时确定的，而不是离线固定。为确保始终为高关键性应用程序提供充足的预算，我们使用离线可调度性分析来确定系统范围内所有高关键性应用程序的总低关键性预算分配。该总预算用作我们模型中的指导，以确定是否需要模式切换。然后，运行时策略根据它们的执行要求在各种应用程序之间分配这个总预算，目的是尽可能推迟模式切换。我们表明，与为每个应用程序使用固定的低临界预算分配的任何策略相比，这种运行时策略能够将模式切换推迟更长的时间。最后，由于我们能够在模式切换之前控制高关键性应用的总预算分配，我们还提出了考虑系统范围目标（例如低关键性应用的可调度性和服务保证）来确定这些预算的技术。我们表明，与为每个应用程序使用固定的低临界预算分配的任何策略相比，这种运行时策略能够将模式切换推迟更长的时间。最后，由于我们能够在模式切换之前控制高关键性应用的总预算分配，我们还提出了考虑系统范围目标（例如低关键性应用的可调度性和服务保证）来确定这些预算的技术。我们表明，与为每个应用程序使用固定的低临界预算分配的任何策略相比，这种运行时策略能够将模式切换推迟更长的时间。最后，由于我们能够在模式切换之前控制高关键性应用的总预算分配，我们还提出了考虑系统范围目标（例如低关键性应用的可调度性和服务保证）来确定这些预算的技术。