MultiPARTES: Multicore Virtualization for Mixed-Criticality Systems

Modern embedded applications typically integrate a multitude of functionalities with potentially different criticality levels into a single system. Without appropriate preconditions, the integration of mixed-criticality subsystems can lead to a significant and potentially unacceptable increase of engineering and certification costs. A promising solution is to incorporate mechanisms that establish multiple partitions with strict temporal and spatial separation between the individual partitions. In this approach, subsystems with different levels of criticality can be placed in different partitions and can be verified and validated in isolation. The MultiPARTES FP7 project aims at supporting mixed- criticality integration for embedded systems based on virtualization techniques for heterogeneous multicore processors. A major outcome of the project is the MultiPARTES XtratuM, an open source hypervisor designed as a generic virtualization layer for heterogeneous multicore. MultiPARTES evaluates the developed technology through selected use cases from the offshore wind power, space, visual surveillance, and automotive domains. The impact of MultiPARTES on the targeted domains will be also discussed. In a number of ongoing research initiatives (e.g., RECOMP, ARAMIS, MultiPARTES, CERTAINTY) mixed-criticality integration is considered in multicore processors. Key challenges are the combination of software virtualization and hardware segregation and the extension of partitioning mechanisms to jointly address significant non-functional requirements (e.g., time, energy and power budgets, adaptivity, reliability, safety, security, volume, weight, etc.) along with development and certification methodology

Implementation of Timing-Event Affinities in Ada/Linux

© Sáez Barona, S.; Real Sáez, J. V.; Crespo, A. | ACM, 2015. This is the author's version of the work. It is posted here for your personal use. Not for redistribution. The definitive Version of Record was published in Adda Letters, http://dx.doi.org/10.1145/2870544.2870546Ada 2012 has introduced mechanisms for exploiting multiprocessor platforms at the application level. These include task affinity control and definition of dispatching domains. However, there are other executable entities defined in the language for which there is no such support to affinity control: event handlers. With event handlers we mean both timing-event and interrupt handlers. This paper discusses the consequences of this lack of functionality and explores implementation issues related with this ability. We propose a working implementation for affinity of timing-event handlers on top of Linux.Sáez Barona, S.; Real Sáez, JV.; Crespo Lorente, A. (2015). Implementation of Timing-Event Affinities in Ada/Linux. Ada Letters. 35(1):80-92. doi:10.1145/2870544.2870546S8092351M. Aldea, A. Burns, M. Gutirrez, and M. González Harbour. Incorporating the deadline floor protocol in Ada. ACM SIGAda Ada Letters -- Proc. of IRTAW 16, XXXIII(2):49--58, 2013.B.B. Brandenburg and J.H. Anderson. Feather-trace: A light-weight event tracing toolkit. In Proc. OSPERT, 2007.A. Burns. A Deadline-Floor Inheritance Protocol for EDF Scheduled Real-Time Systems with Resource Sharing. Technical Report YCS-2012-476, Department of Computer Science, University of York, UK, 2012.A. Burns, M. Gutierrez, M. Aldea, and M. González Harbour. A deadlinefloor inheritance protocol for EDF scheduled embedded real-time systems with resource sharing. IEEE Transactions on Computers, (Online PrePrints), 2014.H. Franke, R. Russell, and M. Kirkwood. Fuss, futexes and furwocks: Fast userlevel locking in linux. In AUUG Conference Proceedings, pages 85--97. AUUG, Inc., 2002.C. Li, C. Ding, and K. Shen. Quantifying the cost of context switch. In Proceedings of the 2007 Workshop on Experimental Computer Science, ExpCS '07. ACM, 2007.R. Spliet, M. Vanga, B.B. Brandenburg, and S. Dziadek. Fast on average, predictable in the worst case: Exploring real-time futexes in litmus. In Proc. IEEE Real-Time Systems Symposium, pages 96--105. IEEE, 2014

Adding multiprocessor and mode change support to the Ada real-time framework

© ACM, 2013. This is the author's version of the work. It is posted here by permission of ACM for your personal use. Not for redistribution. The definitive version was published in Ada Letters, April 2013, Volume XXXIII, Number 1. http://doi.acm.org/10.1145/2492312.2492324[EN] Based on a previous proposal of an Ada 2005 framework of real-time utilities, this paper deals with the extension of that framework to include support for multiprocessor platforms and multiple operating modes and mode changes. The design of the proposed framework is also intended to be amenable to automatic code generation.This work is partly funded by the Vicerrectorado de Investigacion of Universitat Politècnica de València under grant PAID-06-10-2397 and the Europan Commission’s OVERSEE project (FP7-ICT-2009-4, Project ID 248333).Sáez Barona, S.; Real Sáez, JV.; Crespo Lorente, A. (2013). Adding multiprocessor and mode change support to the Ada real-time framework. Ada Letters. 33(1):116-127. https://doi.org/10.1145/2492312.2492324S11612733

Combined Scheduling of Time-Triggered Plans and Priority Scheduled Task Sets

© Owner/Author (2016). This is the author's version of the work. It is posted here for your personal use. Not for redistribution. The definitive Version of Record was published in ACM SIGAda Ada Letters, 36(1), 68-76, http://dx.doi.org/10.1145/10.1145/2971571.2971580.[EN] Preemptive, priority-based scheduling on the one hand, and time-triggered scheduling on the other, are the two major techniques in use for development of real-time and embedded software. Both have their advantages and drawbacks with respect to the other, and are commonly adopted in mutual exclusion. In a previous paper, we proposed a software architecture that enables the combined and controlled execution of time-triggered plans and priority-scheduled tasks. The goal was to take advantage of the best of both approaches by providing deterministic, jitter-controlled execution of time-triggered tasks (e.g., control tasks), coexisting with a set of priority-scheduled tasks, with less demanding jitter requirements. In this paper, we briefly describe the approach, in which the time-triggered plan is executed at the highest priority level, controlled by scheduling decisions taken only at particular points in time, signalled by recurrent timing events. The rest of priority levels are used by a set of concurrent tasks scheduled by static or dynamic priorities. We also discuss several open issues such as schedulability analysis, use of the approach in multiprocessor architectures, usability in mixed-criticality systems and needed changes to make this approach Ravenscar compliant.This work has been partly supported by the Spanish Government’s project M2C2 (TIN2014-56158-C4-1-P-AR) and the European Commission’s project EMC2 (ARTEMIS-JU Call 2013 AIPP-5, Contract 621429).Real Sáez, JV.; Sáez Barona, S.; Crespo Lorente, A. (2016). Combined Scheduling of Time-Triggered Plans and Priority Scheduled Task Sets. Ada Letters. 36(1):68-76. https://doi.org/10.1145/2971571.2971580S6876361T. P. Baker and A. Shaw. The cyclic executive model and Ada. In Proceedings IEEE Real Time Systems Symposium 1988, Huntsville, Alabama, pages 120--129, 1988.P. Balbastre, I. Ripoll, J. Vidal, and A. Crespo. A Task Model to Reduce Control Delays. Real-Time Systems, 27(3):215--236, September 2004.A. Burns and R. Davis. Mixed Criticality Systems - A Review. Technical report, Depatment of Computer Science, University of York, 2013.A. Cervin. Integrated Control and Real-Time Scheduling. PhD thesis, Lund Institute of Technology, April 2003.R. Dobrin. Combining Offline Schedule Construction and Fixed Priority Scheduling in Real-Time Computer Systems. PhD thesis, Mälardalen University, 2005.S. Hong, X. Hu, and M. Lemmon. Reducing Delay Jitter of Real-Time Control Tasks through Adaptive Deadline Adjustments. In IEEE Computer Society, editor, 22nd Euromicro Conference on Real-Time Systems -- ECRTS, pages 229--238, 2010.J. W. S. Liu. Real-Time Systems. Prentice-Hall Inc., 2000.J. Palencia and M. González-Harbour. Schedulability Analysis for Tasks with Static and Dynamic Offsets. In 9th IEEE Real-Time Systems Symposium, 1998.M. J. Pont. The Engineering of Reliable Embedded Systems: LPC1769 edition. Number ISBN: 978-0-9930355-0-0. SafeTTy Systems Limited, 2014.J. Real and A. Crespo. Incorporating Operating Modes to an Ada Real-Time Framework. Ada Letters, 30(1):73--85, April 2010.J. Real, S. Sáez, and A. Crespo. Combining time-triggered plans with priority scheduled task sets. In M. Bertogna and L. M. Pinho, editors, Reliable Software Technologies -- Ada-Europe 2016, volume 9695 of Lecture Notes in Computer Science. Springer, June 2016.S. Sáez, J. Real, and A. Crespo. An integrated framework for multiprocessor, multimoded real-time applications. In M. Brorsson and L. Pinho, editors, Reliable Software Technologies -- Ada-Europe 2012, volume 7308, pages 18--34. Springer-Verlag, June 2012.S. Sáez, J. Real, and A. Crespo. Implementation of Timing-Event Anities in Ada/Linux. Ada Letters, 35(1), April 2015.A. J. Wellings and A. Burns. A Framework for Real-Time Utilities for Ada 2005. Ada Letters, XXVII(2), August 2007

uDDS: A Middleware for Real-time Wireless Embedded Systems

[EN] A Real-Time Wireless Distributed Embedded System (RTWDES) is formed by a large quantity of small devices with certain computing power, wireless communication and sensing/actuators capabilities. These types of networks have become popular as they have been developed for applications which can carry out a vast quantity of tasks, including home and building monitoring, object tracking, precision agriculture, military applications, disaster recovery, industry applications, among others. For this type of applications a middleware is used in software systems to bridge the gap between the application and the underlying operating system and networks. As a result, a middleware system can facilitate the development of applications and is designed to provide common services to the applications. The development of a middleware for sensor networks presents several challenges due to the limited computational resources and energy of the different nodes. This work is related with the design, implementation and test of a micro middleware for RTWDES; the proposal incorporates characteristics of a message oriented middleware thus allowing the applications to communicate by employing the publish/subscribe model. Experimental evaluation shows that the proposed middleware provides a stable and timely service to support different Quality of Service (QoS) levels. © 2011 Springer Science+Business Media B.V.This work was developed as a part of the D2ARS Project supported by CYTED. UNESCO code 120325;330417;120314;120305.González, A.; Mata, W.; Villaseñor, L.; Aquino, R.; Simó Ten, JE.; Chávez, M.; Crespo Lorente, A. (2011). uDDS: A Middleware for Real-time Wireless Embedded Systems. Journal of Intelligent and Robotic Systems. 64(3-4):489-503. https://doi.org/10.1007/s10846-011-9550-zS489503643-4Akyildiz, I.F., Su, W., Sankarasubramaniam, Y., Cayirci, E.: A survey on sensor networks. IEEE Commun. Mag. 40, 102–114 (2002)Aquino, R., González, A., Rangel, V., García, M. Villaseñor, L.A., Edwards-Block, A.: Wireless communication protocol based on EDF for wireless body sensor networks, k. Journal of Applied Sciences and Technology 6(2), 104–114 (2008)Bonnet, P., Gehrke, J.E., Seshadri, P.: Querying the physical world. IEEE Pers. Commun. 7(5), 10–15 (2000)Boonma, P., Suzuki, J.: TinyDDS: an interoperable and configurable publish/subscribe middleware for wireless sensor networks. In: Hinze, A., Buchmann, A. (eds.) Handbook of Research on Advanced Distributed Event-based Systems. Publish/Subscribe and Message Filtering Technologies, IGI Global (2009)Cerpa, A., Elson, J., Hamilton, M., Zhao, J.: Habitat monitoring: application driver for wireless communications technology. ACM SIGCOMM Workshop on Data Communications in Latin America and the Caribbean, Costa Rica (2002)Corsaro, A., Schmidt, D.C.: The design and performace of real-time java middleware. IEEE Trans. Parallel Distrib. Syst. 14(11), issn 1045–9219, 1155–1167 (2003)Culler, D.E., Hong, W.: Wireless sensor networks introduction. Commun. ACM 47(6), 30–33 (2004)Estrin, D., Govindan, R., Heidemann, J.S., Kumar, S.: Next century challenges: scalable coordination in sensor networks. In: Mobile Computing and Networking, pp. 263–270 (1999)Heinzelman, W.B., Murphy, A.L., Carvalho, H.S.: Middleware to support sensor network applications. IEEE Netw. 18, 6–14 (2004)Hill, J., Szewczyk, R., Woo, A., Hollar, S., Culler, D., Pister, K.: System architecture directions for networked sensors. ACM SIGOPS Oper. Syst. Rev. 34(5), 93–104 (2000)Levis, P., Culler, D.: Mate: a tiny virtual machine for sensor networks. In: Proceedings of the 10th International Conference on Achitectural Support for Programming Languages and Operating Systems. San Jose, CA (2002)Liu, T., Martonosi, M.: Impala: a middleware system for managing autonomic, parallel sensor systems. In: Proceedings of the Ninth ACM SIGPLAN Symposium on Principles and Practice of Parallel Programming. San Diego, CA (2003)Mata, W., González, A., Aquino, R., Crespo, A., Ripoll, I., Capel, M.: A wireless networked embedded sistem with a new real-time Kernel PaRTiKle. Electronics, Robotics and Automotive Mechanics Conference, CERMA 2007. ISBN 0-7695-2974-7. Cuernavaca, México (2007)Mata, W., González, A., Crespo, A.: A proposal for real-time middleware for wireless sensor networks. Workshop on Sensor Networks and Applications (WseNA’08). Gramado, Brasil (2008)Mata, W., González, A., Fuentes, G., Fuentes, R., Crespo, A., Carr, D.: Porting jRate(RT-Java) to a POSIX real-time Linux Kernel. Tenth Real-Time Linux Workshop. Colotlán, Jalisco México (2008)MiLAN Project: Available: http://www.futurehealth.rochester.edu/milan (2008)OMG, Data Distribution Service for Real-Time Systems Version 1.2. OMG Technical Document (2007)OMG, Model Driven Architecture (MDA), Document Number ormsc/2001-07-01. Technical report, OMG (2001)OMG, Overview and guide to OMGs architecture, OMG Technical Document formal/03-06-01 (2003)Pardo-Castellote, G., Farabaugh, B., Warren, R.: An Introduction to DDS and Data-centric Communications. Available: http://www.omg.org/news/whitepapers/Intro_To_DDS.pdf (2005)Peiro, S., Masmano, M., Ripoll, I., Crespo, A.: PaRTiKle OS, a replacement of the core of RTLinux. In: 9th Real-Time Linux Workshop (2007)Peiro, S., Masmano, M., Ripoll, I., Crespo, A.: PaRTiKle LPC, port to the LPC2000. Tehth Real-Time Linux Workshop. Colotlán, Jalisco M’exico (2008)Pottie, G.J., Kaiser, W.J.: Wireless integrated networks sensors. Commun. ACM 43(5), 52–58 (2000)Souto, E., Guimaraes, G., Vasconcelos, G., Vieira, M., Rosa, N., Ferraz, C., Kelner, J.: Mires: a publish/subscribe middleware for sensor networks. 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Time and space partition platform for safe and secure flight software.

There are a number of research and development activities that are exploring Time and Space Partition (TSP) to implement safe and secure flight software. This approach allows to execute different real-time applications with different levels of criticality in the same computer board. In order to do that, flight applications must be isolated from each other in the temporal and spatial domains. This paper presents the first results of a partitioning platform based on the Open Ravenscar Kernel (ORK+) and the XtratuM hypervisor. ORK+ is a small, reliable real-time kernel supporting the Ada Ravenscar Computational model that is central to the ASSERT development process. XtratuM supports multiple virtual machines, i.e. partitions, on a single computer and is being used in the Integrated Modular Avionics for Space study. ORK+ executes in an XtratuM partition enabling Ada applications to share the computer board with other applications

Time and space partitioning the EagleEye reference mission

We discuss experiences gained by porting a Software Validation Facility (SVF) and a satellite Central Software (CSW) to a platform with support for Time and Space Partitioning (TSP). The SVF and CSW are part of the EagleEye Reference mission of the European Space Agency (ESA). As a reference mission, EagleEye is a perfect candidate to evaluate practical aspects of developing satellite CSW for and on TSP platforms. The specific TSP platform we used consists of a simulate D LEON3 CPU controlled by the XtratuM separation micro-kernel. On top of this, we run five separate partitions. Each partition ru n s its own real-time operating system or Ada run-time kernel, which in turn are running the application software of the CSW. We describe issues related to partitioning; inter-partition communication; scheduling; I/O; and fault-detection, isolation, and recovery (FDIR

Real-time hierarchical systems with arbitrary scheduling at global level

[EN] Partitioned architectures isolate software components into independent partitions whose execution will not interfere with other partitions, preserving temporal and spatial isolation. Hierarchical scheduling can effectively be used to schedule these systems. Schedulability analysis of hierarchical real-time systems is based on prior knowledge of the local and the global scheduling algorithms. In a partitioned system with safety and security issues and certification assurance levels, global scheduling is usually generated using a static table. Therefore, each partition must allocate task jobs only in the temporal windows reserved for that partition. Even if the static table can come originally from a periodic server or other scheduling policy, the final plan may be modified due to changes in the system requirements. As a consequence, the CPU assignment to a partition does not have to correspond to any known policy. In this case, it is not possible to use existing scheduling analysis for hierarchical systems. This paper studies a new scheduling problem: a hierarchical system in which global policy is not known but provided as a set of arbitrary time windows.This work has been funded by the Spanish government under grant TIN2014-56158-C4-1-P-AR and by the European Commission under FP7-ICT-2013.3.4 Programme with grant 610640Guasque Ortega, A.; Balbastre, P.; Crespo, A. (2016). Real-time hierarchical systems with arbitrary scheduling at global level. Journal of Systems and Software. 119:70-86. https://doi.org/10.1016/j.jss.2016.05.040S708611

Real-Time Systems Overview

[ES] El enorme crecimiento de los sistemas empotrados en los últimos años ha repercutido en un renovado interés por los sistemas de tiempo real. En este artículo se pretende analizar los principales temas que tienen un fuerte impacto en el desarrollo de sistemas de tiempo real y apuntar algunos de los aspectos y propuestas más relevantes en este ámbito. Para ello, se realiza un recorrido por distintos temas tales como las políticas de planificación, los lenguajes más apropiados, los sistemas operativos y los sistemas distribuidos de tiempo real. Más que profundizar en cada uno de estos aspectos, se ha buscado el ofrecer los elementos básicos para tener una visión amplia de este tipo de sistemas.[EN] The great grow in the development of industrial embedded systems has caused a renewed interest on real-time systems. This paper tries to analyze the topics with higher impact in the development of real-time systems, and to identify some of the most important aspects and proposals in this domain. For this purpose, a description of main topics such as scheduling policies, programming languages, operating systems and distributed systems has been presented. The goal has been to provide an insight in the most basic topics, instead of give a deep perspective in some selected items. In this way, the reader can have a broader view of this interesting research area.Alonso, A.; Crespo Lorente, A. (2010). Una Panorámica de los Sistemas de Tiempo Real. Revista Iberoamericana de Automática e Informática industrial. 3(2):7-18. http://hdl.handle.net/10251/146387OJS7183

Propuesta para la Integración de Prácticas de Laboratorio en Intensificaciones de la titulación de ITIS

Los cambios en los planes de estudios de las ingenierías técnicas hacen que el profesorado en general se plantee cambios en la forma de impartir la docencia. En el presente artículo se propone la utilización de una plataforma común para la realización de actividades prácticas para asignaturas pertenecientes a una misma intensificación. Esto permite, por una parte, aunar esfuerzos a la hora de realizar la puesta en marcha de las prácticas, y, por otra, ofrecer al alumno una visión global a un problema complejo