WCRT Analysis for a Uniprocessor with a Unified Prioritized Cache

In this paper, we investigate the problem of inter-task cache interference in preemptive multi-tasking real-time systems. A prioritized cache is used to reduce cache conflicts among tasks by partitioning the cache. Cache partitions are assigned to tasks according to their priorities. We extend a known tool, SYMTA, in order to estimate the Worst Case Execution Time of each task executing on a uniprocessor with a unified prioritized L1 cache. Furthermore, we apply a formal timing analysis approach to estimate the Worst Case Response Time (WCRT) of each task using the prioritized cache. Our WCRT analysis handles nested preemptions. WCRT using a prioritized cache is compared to using a conventional set associative cache of the same size and associativity. Our experiments show that the WCRT estimate can be reduced up to 26 % when a prioritized cache is used