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International audienceWhen integrating mixed critical systems on a multi/many-core, one challenge is to ensure predictability for high crit-icality tasks and an increased utilization for low criticality tasks. In this paper, we address this problem when several high criticality tasks with different deadlines, periods and offsets are concurrently executed on the system. We pro-pose a distributed run-time WCET controller that works as follows: (1) locally, each critical task regularly checks if the interferences due to the low criticality tasks can be toler-ated, otherwise it decides their suspension; (2) globally, a master suspends and restarts the low criticality tasks based on the received requests from the critical tasks. Our ap-proach has been implemented as a software controller on a real multi-core COTS system with significant gains 1

Mixed-criticality systems are promoted in industry due to their potential to reduce size, weight, power, and cost. Nonetheless, deploying mixed-criticality applications on commercial multi-core platforms remains a highly challenging problem. To name a few reasons: (i) Industrial mixed-criticality applications are usually complex reactive applications, which cannot be specified by traditional, e.g., dataflow-based, models of computation. Appropriate mixed-criticality models of computation built upon Vestal's assumptions are missing; (ii) Scheduling such applications on multicores with shared resources, such as memory buses, requires that any timing interference among applications of different criticality is bounded in order to guarantee-the necessary for certification-temporal isolation and to enable incremental design; (iii) The implementation of isolation-preserving mixed-criticality schedulers is itself subject to certification. Hence, it needs to be not only efficient, but also provably correct. This paper proposes, for the first time, a complete design flow covering all aspects from specification, using a novel mixed-criticality aware model of computation (DOL-Critical), to correct-by-construction implementation, using the principle 'what you verify is what you generate' which is based on a novel variant of task automata (BIP). We demonstrate the applicability of our design flow with an industrial avionic test case on the state-of-the-art Kalray MPPA R-256. Keywords real-time systems • mixed-criticality systems • multi-core scheduling • rigorous design • software synthesis • avionics

Work for this paper was executed within the SAFURE project. The project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 644080.

Abstract:Mixed-criticality systems (MCS) aim at boosting the integration density in safety-critical systems, resulting into efficient systems, while simultaneously providing increased performance. The DREAMS project provides a cross-domain architectural style for MCS based on networked, virtualized multicores controlled by hierarchical resource managers. However, the availability of a platform is only one side of the coin: deploying mixed-critical applications to shared resources typically requires design-time configurations (e.g., to ensure real-time constraints or separation constraints mandated by safety regulations). These configurations are the outcome of complex optimization problems which are intractable in a manual process that also hardly can guarantee the consistency of all deployable artefacts nor their traceability to the requirements. However, existing toolchains lack support for MCS integration, and particularly DREAMS' advanced platform capabilities. We present an integrated model-driven toolchain and the underlying metamodels covering all relevant aspects of MCS including applications, timing, platforms, deployments, configurations and annotations for extra-functional properties such as safety. The approach focuses on the left branch of the V-cycle, and ranges from product-line and design space exploration to resource allocation and configuration generation. We report on the integration of exploration tools and a reconfiguration graph synthesizer, and evaluate the resulting toolchains in two use cases consisting of a product-line of wind power control applications and an avionic subsystem respectively