Availability enhancement and analysis for mixed-criticality systems on multi-core

In the critical systems domain, Mixed Criticality Systems (MCS) improve considerably the usage of computation resources by running tasks with different levels of criticality on multi-core processors. To ensure the safety of MCS, services provided by low criticality tasks are degraded or stopped whenever high criticality tasks need more computation time than initially credited. The evaluation of this degradation is hardly considered in the literature although low criticality services are of prime importance for the quality of service (QoS) of critical systems. In this paper, we propose a method to evaluate the availability of low criticality services, i.e. how often these services are delivered in MCS. We also propose a task model that improves this availability, demonstrated thanks to our evaluation method on an illustrative example of MCS.