No abstract

RésuméCet article est la continuation d'un portefeuille de recherche sur la sécurité des composants sur étagère, dont l'utilisation se répand dans les systèmes avioniques complexes (Condra, 2014). Parmi les composants complexes sur étagère, les processeurs multicoeurs sont l'un des plus étudiés pour leur impact potentiel sur la sécurité associée à l'indéterminisme (Bieth, 2013). Un article précédent (Jean, 2015) discuta des aspects temporels ainsi que des méthodes pour déterminer le Worst-case Execution Time (WCET). Cet article se concentre sur la détermination des types d'erreurs spécifiques des processeurs multicoeurs, la détermination de leurs effets, les moyens de détection et de mitigation de ces erreurs, ainsi que l'existence de critères pour contenir la panne résultante ou pour récupérer de cette erreur. SummaryThis paper is a continuation of a research thrust on safety assurance for Commercial Off-the-Shelf (COTS) which use is becoming widely spread in complex avionics (Condra, 2014). Among complex COTS, multicore processors are one of the components being investigated in terms of their potential safety impacts relative to non-determinism (Bieth, 2013). A previous paper (Jean, 2015) addressed timing issues and the methods to determine Worst-case Execution Time (WCET). The present paper focuses on the determination of error types specific to multicore processors, the determination of the effects of these failure modes, the means of detection and mitigation of these errors, and the existence of criteria for containment of the resulting failure or recovery from the error.

Most safety-critical avionics systems are defined as "hard real time". That means they must deliver their function within pre-defined deadlines. Missing a single deadline at system level is considered as a failure condition that may be catastrophic. At software level, this is a single failure that must be mitigated with appropriate means to prevent that failure condition. Real-time requirements are addressed in software components by Worst Case Execution Time (WCET) evaluations. Several methods have been explored in the literature, for which classifications have been proposed according to their techniques and precision of their results. However, these classifications do not consider the contribution of WCET evaluation techniques to safety processes. In this paper, we present a safety process that integrates WCET evaluation on embedded software. This process allows us to highlight the benefits and limits that WCET evaluation methods bring in industrial practices.

No abstract

Most safety-critical avionics systems are defined as "hard real time". That means they must deliver their function within pre-defined deadlines. Missing a single deadline at system level is considered as a failure condition that may be catastrophic. At software level, this is a single failure that must be mitigated with appropriate means to prevent that failure condition. Real-time requirements are addressed in software components by Worst Case Execution Time (WCET) evaluations. Several methods have been explored in the literature, for which classifications have been proposed according to their techniques and precision of their results. However, these classifications do not consider the contribution of WCET evaluation techniques to safety processes. In this paper, we present a safety process that integrates WCET evaluation on embedded software. This process allows us to highlight the benefits and limits that WCET evaluation methods bring in industrial practices.