Reconciling the Tension Between Hardware Isolation and Data Sharing in Mixed-Criticality, Multicore Systems

Recent work involving a mixed-criticality framework called MC2 has shown that, by combining hardware-management techniques and criticality-aware task provisioning, capacity loss can be significantly reduced when supporting real-time workloads on multicore platforms. However, as in most other prior research on multicore hardware management, tasks were assumed in that work to not share data. Data sharing is problematic in the context of hardware management because it can violate the isolation properties hardware-management techniques seek to ensure. Clearly, for research on such techniques to have any practical impact, data sharing must be permitted. Towards this goal, this paper presents a new version of MC2 that permits tasks to share data within and across criticality levels through shared memory. Several techniques are presented for mitigating capacity loss due to data sharing. The effectiveness of these techniques is demonstrated by means of a large-scale, overhead-aware schedulability study driven by micro-benchmark data.