Cache-Aware Timing Analysis of Limited Preemption Scheduling With Fixed Preemption Points in Set-Associative Mapping

In a limited preemption real-time system with a cache architecture, scheduling analysis must not only consider the execution time of tasks and the blocking of lower-priority tasks, but also precisely analyze cache-related preemption delays (CRPD). In set-associative mapping, the existing schedulability analysis for limited preemption scheduling with fixed preemption points employs overly conservative strategies for calculating cache-related preemption delays, which leads to pessimistic results in schedulability analysis. In this paper, we propose a cache-aware timing analysis method utilizing the oldest memory block in cache sets for analyzing sporadic real-time tasks with fixed preemption points in set-associative mapping. This method can more accurately analyze the cache-related preemption delays by examining whether memory blocks in the cache have been evicted. Experimental results demonstrate that the method proposed in this paper surpasses the best existing approaches, achieving a 17% higher recognition rate for schedulable task sets under the group concatenated mapping strategy.