Tolerating Permanent Faults with Low-Energy Overhead in Multicore Mixed-Criticality Systems

Abstract

Due to the battery-operated nature of embedded Mixed-Criticality Systems, simultaneous energy and reliability management is a cru-cial issue in designing these systems. We propose two comprehensive schemes, MC-2S and MC-4S, which tolerate permanent faults through exploiting the inherent redundancy of multicore systems for applying standby-sparing technique and maintaining the system re-liability against transient faults with low energy overhead. In these schemes, two copies of each high-criticality task are scheduled on different cores to guarantee their timeliness in case of permanent fault occurrence. In order to guarantee the quality of service of low-criticality tasks, in the MC-2S scheme, sufficient slack time is reserved to schedule a backup task for each low criticality task on an al-ternative core. The MC-4S scheme exploits semi-partitioned scheduling in which low-criticality tasks migrate to other cores in case of permanent fault or overrun occurrence on one of the cores. We also develop a Demand Bound Function schedulability analysis to guar-antee the timeliness, and propose a preference-oriented scheduling algorithm along with reliability-aware DVFS method for energy saving. The proposed schemes provide up to 57% (39% on average) energy saving, and enhance the acceptance ratio of the system significantly in comparison to other state-of-the-art methods.