How windows size and number can influence the schedulability of hierarchically-scheduled time-partitioned distributed real-time systems

Partitioning techniques are implemented in the development of safety-critical applications to ensure isolation among components. An adequate scheduling of the execution of such partitions is a key challenge so that applications meet the hard deadlines imposed. In this work, we study the effect of different partition window configuration parameters, with the aim of analyzing their impact in the worst-case response times of system tasks. This is the first step in the development of an algorithm for optimizing partition windows in hierarchically-scheduled time-partitioned distributed systems

Optimization in Heterogeneous Distributed Real-Time Systems based on Partitioning

In this work, a solution that can be applied to the RTSS 2022’s Industry Challenge is proposed. It relies on a real-time system model and a set of schedulability analysis and optimization tools, enabling the design of safety-critical applications compliant with timing requirements. The presented toolchain is enhanced with a novel task allocation technique, which leverages sensitivity analysis and that can be applied to heterogeneous systems, to provide promising solutions that improve state-of-the-art algorithms’ performance.This work was supported in part by MCIN/ AEI /10.13039/501100011033/ FEDER “Una manera de hacer Europa” under grant PID2021-124502OB-C42 (PRESECREL)

Response-Time Analysis of Multipath Flows in Hierarchically-Scheduled Time-Partitioned Distributed Real-Time Systems

Modern industrial cyberphisical systems exhibit increasingly complex execution patterns like multipath end-to-end flows, that force the real-time community to extend the schedulability analysis methods to include these patterns. Only then it is possible to ensure that applications meet their deadlines even in the worst-case scenario. As a driving motivation, we present a real industrial application with safety requirements, that needs to be re-factored in order to leverage the features of new execution paradigms such as time partitioning. In this context we develop a new response-time analysis technique that provides the capacity of obtaining the worst-case response time of multipath flows in time-partitioned hierarchical schedulers and also in general fixed-priority (FP) real-time systems. We show that the results obtained with the new analysis reduce the pessimism of the currently used holistic analysis approach.This work was supported in part by the Doctorados Industriales 2018 program from the University of Cantabria and the Spanish Government and FEDER funds (AEI/FEDER, UE) under Grant TIN2017-86520-C3-3-R (PRECON-I4)

A review on optimization techniques for the deployment and scheduling of distributed real-time systems

RESUMEN: En las ultimas tres décadas, se ha realizado un gran número de propuestas sobre la optimización del despliegue y planificación de sistemas de tiempo real distribuidos bajo diferentes enfoques algorítmicos que aportan soluciones aceptables a este problema catalogado como NP-difícil. En la actualidad, la mayor parte de los sistemas utilizados en el sector industrial son sistemas de criticidad mixta en los que se puede usar la planificación cíclica, las prioridades fijas y el particionado, que proporciona aislamiento temporal y espacial a las aplicaciones. Así, en este artículo se realiza una revisión de los trabajos publicados sobre este tema y se presenta un análisis de las diferentes soluciones aportadas para sistemas de tiempo real distribuidos basados en las políticas de planificación que se están usando en la práctica. Como resultado de la comparación, se presenta una tabla a modo de guía en la que se relacionan los trabajos revisados y se caracterizan sus soluciones.ABSTRACT: In the last three decades, a large number of proposals has been carried out for the optimization of the deployment and scheduling of distributed real-time systems under different algorithmic approaches that provide acceptable solutions for this NP-hard problem. Nowadays, most of the systems used in industry are mixed-criticallity systems which use cyclic scheduling, fixed-priority scheduling and partitioning, which provides both temporal and spatial isolation in the execution of applications. Thus, in this work a review of the works published on this topic is performed, as well as an analysis of the different proposed solutions for distributed real-time systems based on the scheduling policies that are used in practice. As a result of the comparison, a table intended as a guide is elaborated in which all the reviewed works are reported and their solutions are characterized.Este trabajo ha sido financiado en parte por el Gobierno de España y los fondos FEDER (AEI /FEDER, UE) en el proyecto TIN2017-86520-C3-3-R (PRECON-I4)