Shared caches in multicore processors introduce serious difficulties in providing guarantees on the real-time properties of embedded software due to the interaction and the resulting contention in the shared caches. To address this problem, we develop a new schedulability analysis for real-time multicore systems with shared caches, globally scheduled by Earliest Deadline First (EDF) and Fixed Priority (FP) algorithms. We construct an integer programming formulation, which can be transformed to an integer linear programming formulation, to calculate an upper bound on cache interference exhibited by a task within a given execution window. Using the integer programming formulation, an iterative algorithm is presented to obtain the upper bound on cache interference a task may exhibit during one job execution. The upper bound on cache interference is subsequently integrated into the schedulability analysis to derive a new schedulability condition. A range of experiments is performed to investigate how the schedulability is degraded by shared cache interference. We also evaluate the schedulability performance of EDF against FP scheduling over randomly generated tasksets. Our empirical evaluations show that EDF is better than FP scheduling in terms of the number of task sets deemed schedulable.

中文翻译：

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共享缓存多核系统全局调度的可调度性分析


由于共享缓存中的交互和由此产生的争用，多核处理器中的共享缓存在保证嵌入式软件的实时特性方面带来了严重的困难。为了解决这个问题，我们为具有共享缓存的实时多核系统开发了一种新的可调度性分析，通过最早截止时间优先（EDF）和固定优先级（FP）算法进行全局调度。我们构建了一个整数规划公式，可以将其转换为整数线性规划公式，以计算给定执行窗口内的任务所表现出的缓存干扰的上限。使用整数规划公式，提出了一种迭代算法来获取任务在一次作业执行期间可能表现出的缓存干扰的上限。随后将缓存干扰的上限集成到可调度性分析中，以得出新的可调度性条件。进行了一系列实验来研究共享缓存干扰如何降低可调度性。我们还评估了 EDF 与 FP 调度在随机生成的任务集上的可调度性性能。我们的实证评估表明，就可调度的任务集数量而言，EDF 优于 FP 调度。