Shared caches in multicores challenge Worst-Case Execution Time (WCET) estimation due to inter-task interferences. Hard-ware and software cache partitioning address this issue although they complicate data sharing among tasks and the Operating System (OS) task scheduling and migration. In the context of Probabilistic Timing Analysis (PTA) time-randomised caches are used. We propose a new hardware mechanism to control inter-task interferences in shared time-randomised caches with-out the need of any hardware or software partitioning. Our proposed mechanism effectively bounds inter-task interferences by limiting the cache eviction frequency of each task, while providing tighter WCET estimates than cache partitioning al-gorithms. In a 4-core multicore processor setup our proposal improves cache partitioning by 56% in terms of guaranteed per-formance and 16% in terms of average performance.

Peer Reviewed