Explicit Reservation of Cache Memory in a Predictable, Preemptive Multitasking Real-time System

We describe and evaluate explicit reservation of cache memory to reduce the cache-related preemption de-lay (CRPD) observed when tasks share a cache in a preemptive multitasking hard real-time system. We demonstrate the approach using measurements obtained from a hardware prototype, and present schedu-lability analyses for systems that share a cache by explicit reservation. These analyses form the basis for a series of experiments to further evaluate the approach. We find that explicit reservation is most useful for larger task sets with high utilization. Some task sets cannot be scheduled with a conventional cache, but are schedulable with explicit reservation. 1