Ingredients for the specification of mixed-criticality real-time systems

Models for real-time computing are available with different timing requirements. With the ongoing trend towards integration of services of different degrees of timing strictness on one single platform, there is a need to specify computing models for such scenarios. In this paper we study the requirements to specify mixed criticality real-time systems (MCRTS). Mixed criticality systems have been studied intensively over the last years. Existing formulations of the scheduling problem for mixed criticality systems do not consider the different timing strictness requirements of the tasks. In this paper we argue that mixed criticality properties as well as real-time properties have to be considered together in order to provide the maximal utility of a system. Based on that argument we present a list of ingredients required for the specification of MCRTS. We outline conceptually, how a system can take advantage of having MCRTS specifications available. We present some examples to show the usefulness of specifying MCRTS properties for real-life systems.Final Accepted Versio

ATMP: An Adaptive Tolerance-based Mixed-criticality Protocol for Multi-core Systems

© 2018 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted ncomponent of this work in other works.The challenge of mixed-criticality scheduling is to keep tasks of higher criticality running in case of resource shortages caused by faults. Traditionally, mixedcriticality scheduling has focused on methods to handle faults where tasks overrun their optimistic worst-case execution time (WCET) estimate. In this paper we present the Adaptive Tolerance based Mixed-criticality Protocol (ATMP), which generalises the concept of mixed-criticality scheduling to handle also faults of other nature, like failure of cores in a multi-core system. ATMP is an adaptation method triggered by resource shortage at runtime. The first step of ATMP is to re-partition the task to the available cores and the second step is to optimise the utility at each core using the tolerance-based real-time computing model (TRTCM). The evaluation shows that the utility optimisation of ATMP can achieve a smoother degradation of service compared to just abandoning tasks