Cache-Related Preemption Delays and Real-Time Scheduling: A Survey for Uniprocessor Systems

The trend in nowadays real-time embedded systems is to use commercial off-the-shelf com-ponents, and in particular CPUs with cache memories. But because of the way the cache is working, additional delays known as Cache-Related Preemption Delays (CRPDs) might occur as soon as preemptive scheduling is considered. These CRPDs make the predictability problem more complex and may even threaten the system schedulability. This article presents different existing strategies to deal with CRPD issues. These strategies can focus on reducing the CRPDs at the cache level or can work at the scheduling level to control the number of preemptions. Combinations between those different methods are also presented