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  • 51.
    Becker, Matthias
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Nicolic, Borislav
    Technische Universität Braunschweig, Germany.
    Dasari, Dakshina
    Robert Bosch GmbH, Renningen, Germany.
    Åkesson, Benny
    CISTER/INESC-TEC, ISEP, Portugal.
    Nélis, Vincent
    CISTER/INESC-TEC, ISEP, Portugal.
    Behnam, Moris
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Partitioning and Analysis of the Network-on-Chip on a COTS Many-Core Platform2017In: 23rd IEEE Real-Time and Embedded Technology and Applications Symposium RTAS'17, 2017, p. 101-112Conference paper (Refereed)
    Abstract [en]

    Many-core processors can provide the computational power required by future complex embedded systems. However, their adoption is not trivial, since several sources of interference on COTS many-core platforms have adverse effects on the resulting performance. One main source of performance degradation is the contention on the Network-on-Chip, which is used for communication among the compute cores via the off- chip memory. Available analysis techniques for the traversal time of messages on the NoC do not consider many of the architectural features found on COTS platforms. In this work, we target a state-of-the-art many-core processor, the Kalray MPPA R . A novel partitioning strategy for reducing the contention on the NoC is proposed. Further, we present an analysis technique dedicated to the proposed partitioning strategy, which considers all architectural features of the COTS NoC. Additionally, it is shown how to configure the parameters for flow-regulation on the NoC, such that the Worst-Case Traversal Time (WCTT) is minimal and buffers never overflow. The benefits of our approach are evaluated based on extensive experiments that show that contention is significantly reduced compared to the unconstrained case, while the proposed analysis outperforms a state-of-the-art analysis for the same platform. An industrial case study shows the tightness of the proposed analysis.

  • 52.
    Becker, Matthias
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Sandström, K.
    ABB Corporate Research, Västerås, Sweden .
    Behnam, Moris
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Limiting temperature gradients on many-cores by adaptive reallocation of real-time workloads2014In: 19th IEEE International Conference on Emerging Technologies and Factory Automation, ETFA 2014, 2014, p. Article number 7005241-Conference paper (Refereed)
    Abstract [en]

    The advent of many-core processors came with the increase in computational power needed for future applications. However new challenges arrived at the same time, especially for the real-time community. Each core on such a processor is a heat source and uneven usage can lead to hot spots on the processor, affecting its lifetime and reliability. For real-time systems, it is therefore of paramount importance to keep the temperature differences between the individual cores below critical values, in order to prevent premature failure of the system. We argue that this problem can not be solved by traditional approaches, since the growing number of cores makes them intractable. We rather argue to split the problem in the spacial domain and control the temperature on core level. The cores control their temperature by rearranging the load in a predictable manner during runtime. To achieve this, a feedback controller is implemented on each core. We conclude our work with a simulation based evaluation of the proposed approach comparing its performance against a previously presented algorithm. 

  • 53.
    Becker, Matthias
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Sandström, Kristian
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Behnam, Moris
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    A Many-Core based Execution Framework for IEC 61131-32015In: IECON 2015 - 41st Annual Conference of the IEEE Industrial Electronics Society, 2015, p. 4525-4530, article id 7392805Conference paper (Refereed)
    Abstract [en]

    Programmable logic controllers are widely used for the control of automationsystems. The standard IEC 61131-3 defines the execution model as well as theprogramming languages for such systems. Nowadays, actuators and sensorsconnect to the programmable logic controller via automation buses. While suchbuses, as well as the sensors and actuators, become more and more powerful, ashift away from the current distributed operation of automation systems, closeto the field level, becomes possible. Instead, execution of complex controlfunctions can be relocated to more powerful hardware, and technologies. Thispaper presents an execution framework for IEC 61131-3, based on a many-coreprocessors. The presented execution model exploits the characteristics of theIEC 61131-3 applications as well as the characteristics of the many-core processor,yielding a predictable execution. We present the platform architectureand an algorithm to allocate a number of IEC 61131-3 conform applications.Experimental as well as simulation based evaluation is provided.

  • 54.
    Becker, Matthias
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Sandström, Kristian
    ABB Corporate Research, Västerås, Sweden.
    Behnam, Moris
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Dynamic Power Management for Thermal Control of Many-Core Real-Time Systems2014In: Sigbed Review, ISSN 1551-3688, Vol. 11, no 3, p. 26-29Article in journal (Refereed)
    Abstract [en]

    Many-Core systems, processors incorporating numerous cores interconnected by a Network on Chip (NoC), provide the computing power needed by future applications. High power density caused by the steadily shrinking transistor size, which is still following Moore's law, leads to a number of problems such as overheating cores, affecting processor reliability and lifetime. Embedded real-time systems are exposed to a changing ambient temperature and thus need to adapt their configuration in order to keep the individual core temperature below critical values. %Targeting embedded real-time systems, systems need to adapt to changing environments. In our approach a hysteresis controller is implemented on each core, triggering a redistribution of the cores and the transition into idle state allowing the core to cool down. We propose two approaches, one global and one local approach, to redistribute the tasks and relive overheating cores during runtime. We evaluate the two proposed approaches by comparing them against each other based on simulations.

  • 55.
    Becker, Matthias
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Sandström, Kristian
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Behnam, Moris
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Increased Reliability of Many-Core Platforms through Thermal Feedback Control2014In: Performance, Power and Predictability of Many-Core Embedded Systems 3PMCES'14, Dresden, Germany, 2014Conference paper (Refereed)
    Abstract [en]

    In this paper we present a low overhead thermal management approach to increase reliability of many-core embedded real-time systems. Each core is controlled by a feedback controller. We adapt the utilization of the core in order to decrease the dynamic power consumption and thus the corresponding heat development. Sophisticated control mechanisms allow us to migrate the load in advance, before reaching critical temperature values and thus we can migrate in a safe way with a guarantee to meet all deadlines.

  • 56.
    Becker, Matthias
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Sandström, Kristian
    ABB Corporate Research.
    Behnam, Moris
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Mapping Real-Time Tasks onto Many-Core Systems considering Message Flows2014In: Proceedings of the Work-in-Progress Session of the 20th IEEE Real-Time and Embedded Technology and Applications Symposium, Berlin, Germany, 2014, p. 17-18Conference paper (Refereed)
    Abstract [en]

    In this work we focus on the task mapping problem for many-core real-time systems. The growing number of cores connected by a Network-on-Chip (NoC) calls for sophisticated mapping techniques to meet the growing demands of real-time applications. Hardware should be used in an efficient way such that unnecessary resource usage is avoided. Because of the NP-hardness of the problem, heuristic and meta-heuristic techniques are used to find good solutions. We further consider periodic communication between tasks and we focus on a static mapping solution.

  • 57.
    Becker, Matthias
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Schmidt, Adriaan
    Fraunhofer Institute for Embedded Systems and Communication Technologies ESK, Germany.
    Orehek, Martin
    University of Applied Sciences Munich, Germany.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Saving Energy by Means of Dynamic Load Management in Embedded Multicore Systems2014In: Proceedings of the 9th IEEE International Symposium on Industrial Embedded Systems, SIES 2014, 2014, p. 11-20Conference paper (Refereed)
    Abstract [en]

    Load balancing is widely used to optimize response times and throughput of software systems. When considering embedded systems, however, additional optimization goals like energy consumption become relevant. In this paper, we explore the use of load balancing in embedded multicore applications. We present extensions to three prominent load balancing schemes, enabling them to dynamically scale the number of active cores. We integrated the algorithms in a proprietary operating system targeting multicore embedded systems. Our evaluation, which is based on a telecommunication (VoIP) scenario, shows that a significant reduction in energy consumption is possible.

  • 58.
    Begum, Shahina
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Behnam, Moris
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Larsson, Thomas B
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Sandström, Kristian
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Towards a Compositional Service Architecture for Real-Time Cloud Robotics2016In: ACM SIGBED Review, E-ISSN 1551-3688, p. 63-64Article in journal (Refereed)
    Abstract [en]

    In this paper we present our ongoing work towards a compositional service architecture that integrates cloud technology for computational capacity targeting real-time robotics applications. In particular we take a look at the challenges inherent within the data center where the services are executing. We outline characteristics of the services used in the real-time cloud robotics application, along with the service management and corresponding task model used to execute services. We identify several key central challenges that must be addressed towards integrating cloud technology in real-time robotics.

  • 59.
    Behnam, Moris
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Inam, Rafia
    Mälardalen University, School of Innovation, Design and Engineering.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering.
    Sjödin, Mikael
    Mälardalen University, School of Innovation, Design and Engineering.
    Multi-core Composability in the Face of Memory Bus Contention2012Conference paper (Refereed)
    Abstract [en]

    In this paper we describe the problem of achieving composability of independently developed real-time subsystems to be executed on a multicore platform.We evaluate existing work for achieving real-time performance on multicores and illustrate their lack with respect to composability. To better address composability we present a multi-resource server-based scheduling technique to provide predictable performance when composing multiple subsystems on a multicore platform. To achieve composability also on multicore platforms, we propose to add memory-bandwidth as an additional server resource. Tasks within our multi-resource servers are guaranteed both CPU- and memory-bandwidth; thus the performance of a server will become independent of resource usage by tasks in other servers. We are currently implementing multi-resource servers for the Enea’s OSE operating system for a P4080 8-core processor to be tested with software for a 3G-basestation.

  • 60.
    Behnam, Moris
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Nemati, Farhang
    Mälardalen University, School of Innovation, Design and Engineering.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering.
    Grahn, Håkan
    Blekinge Institute of Technology.
    Towards an Efficient Approach for Resource Sharing in Real-Time Multiprocessor Systems2011In: SIES 2011 - 6th IEEE International Symposium on Industrial Embedded Systems, Conference Proceedings, IEEE , 2011, p. 99-102Conference paper (Refereed)
    Abstract [en]

    Supporting resource sharing in multiprocessor architectures is one of the problems which may limit the benefits that can be archived using this type of architecture. Many approaches and algorithms have been proposed to support resource sharing, however, most of them impose either high blocking times on tasks or require a large memory size. In this paper we investigate the possibility of combining the lock-based approaches and wait-free approaches (using multiple buffers) in order to decrease both the blocking time that may affect the schedulability of tasks and the required memory. To achieve this, we propose a solution based on evaluating the maximum allowed blocking time on each task according to the schedulability analysis, and then find the minimum memory requirement for each resource such that it limits the blocking times on tasks to be less than the maximum allowed blocking times.

  • 61.
    Behnam, Moris
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering.
    Bril, Reinder
    Eindhoven University of Technology, The Netherlands.
    Bounding the number of self-blocking occurrences of SIRAP2010In: Proceedings - Real-Time Systems Symposium, 2010, p. 61-72Conference paper (Refereed)
    Abstract [en]

    This paper presents a new schedulability analysis for hierarchically scheduled real-time systems executing on a single processor using SIRAP; a synchronization protocol for inter subsystem task synchronization. We show that it is possible to bound the number of self-blocking occurrences that should be taken into consideration in the schedulability analysis of subsystems. Correspondingly, we present two novel schedulability analysis approaches with proof of correctness for SIRAP. An evaluation suggests that this new schedulability analysis can decrease the analytical subsystem utilization significantly

  • 62.
    Behnam, Moris
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering.
    Bril, Reinder
    Eindhoven University of Technology, The Netherlands.
    Refining SIRAP with a Dedicated Resource Ceiling for Self-Blocking2009In: 9th ACM & IEEE International Conference on Embedded Software, 2009, p. 157-166Conference paper (Refereed)
  • 63.
    Behnam, Moris
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering.
    Bril, Reinder
    Eindhoven University of Technology, The Netherlands.
    Schedulability analysis of synchronization protocols based on overrun without payback for hierarchical scheduling frameworks revisited2010Report (Other academic)
    Abstract [en]

    In this paper, we show that both global as well as local schedulability analysis of synchronization protocols based on the stack resource protocol (SRP) and overrun without payback for hierarchical scheduling frameworks based on fixed-priority pre-emptive scheduling (FPPS) are pessimistic.We present improved global and local schedulability analysis,illustrate the improvements by means of examples, and show that the improved global analysis is both uniform and sustainable.We evaluate the improved global and local schedulabilityanalysis based on an extensive simulation study and comparethe results with the existing analysis.

  • 64.
    Behnam, Moris
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering.
    Fisher, Nathan
    Department of Computer Science, Wayne State University.
    On Optimal Real-time Subsystem-Interface Generation in the Presence of Shared Resources2010In: Proceedings of the 15th IEEE International Conference on Emerging Technologies and Factory Automation, ETFA 2010, Bilbao, Spain, 2010Conference paper (Refereed)
    Abstract [en]

    The Hierarchical Scheduling Framework (HSF) has been introduced as a design-time framework enabling compositional schedulability analysis of embedded software systems with real-time properties. However, supporting resource sharing in HSF is a major challenge, since it increases the amount of CPU resources required to guarantee schedulability of the hard real time tasks, and it decreases the composability at the system level. In this paper, we focus on a compositional framework called the bounded-delay resource open environment (BROE) server, and we identify key parameters of this framework that have a great effect on how the framework will utilize CPU resources. In addition, we show how to select optimal values for these parameters in order to reduce the required CPU resource

  • 65.
    Behnam, Moris
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering.
    J. Bril, Reinder
    Mälardalen University, School of Innovation, Design and Engineering.
    A new approach for global synchronization in hierarchical scheduled real-time systems2009In: Work-in-Progress (WiP) session of the 21st Euromicro Conference on Real-Time Systems (ECRTS'09), 2009Conference paper (Refereed)
  • 66.
    Behnam, Moris
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering.
    J. Bril, Reinder
    Technische Universiteit Eindhoven.
    Improved SIRAP analysis for synchronization in hierarchical scheduled real-time systems2009In: Proceedings of 14th IEEE International Conference on Emerging Techonologies and Factory (ETFA'09), 2009Conference paper (Refereed)
    Abstract [en]

    We present our ongoing work on synchronization in hierarchical scheduled real-time systems, where tasks are scheduled using fixed-priority pre-emptive scheduling. In this paper, we show that the original local schedulability analysis of the synchronization protocol SIRAP is very pessimistic when tasks of a subsystem access many global shared resources. The analysis therefore suggests that a subsystem requires more CPU resources than necessary. A new way to perform the schedulability analysis is presented which can make the SIRAP protocol more efficient in terms of calculated CPU resource needs.

  • 67.
    Behnam, Moris
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering.
    J. Bril, Reinder
    Technische Universiteit Eindhoven.
    Tighter Schedulability Analysis of Synchronization Protocols Based on Overrun Without Payback for Hierarchical Scheduling Frameworks2011In: 16th IEEE International Conference on Engineering of Complex Computer Systems (ICECCS'11), Los Alamitos: IEEE Computer Society, 2011, p. 35-44Conference paper (Refereed)
  • 68.
    Behnam, Moris
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering.
    Shin, Insik
    Mälardalen University, School of Innovation, Design and Engineering.
    A Hierarchical Approach for Reconfigurable and Adaptive Embedded Systems2008In: APRES'08 Adaptive and Reconfigurable Embedded Systems: First International Workshop on Adaptive and Reconfigurable Embedded Systems, 2008, p. 51-54Conference paper (Refereed)
    Abstract [en]

    Adaptive and reconfigurable embedded systems have been gaining an increasing interest in the past year from both academics and industry. This paper presents our work on hierarchical scheduling frameworks (HSF) intended as a backbone architecture facilitating the implementation of operating system support for adaptability and reconfigurability.

  • 69.
    Behnam, Moris
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering.
    Shin, Insik
    Åsberg, Mikael
    Mälardalen University, School of Innovation, Design and Engineering.
    Bril, Reinder
    Technische Universiteit Eindhoven.
    Towards Hierarchical Scheduling in VxWorks2008In: OSPERT 2008, Proceedings of the Fourth International Workshop on Operating Systems Platforms for Embedded Real-Time Applications, 2008, p. 63-72Conference paper (Refereed)
    Abstract [en]

    Over the years, we have worked on hierarchical schedulingframeworks from a theoretical point of view. In thispaper we present our initial results of the implementationof our hierarchical scheduling framework in a commercialoperating system VxWorks. The purpose of the implementationis twofold: (1) we would like to demonstrate feasibilityof its implementation in a commercial operating system,without having to modify the kernel source code, and (2) wewould like to present detailed figures of various key propertieswith respect to the overhead of the implementation.During the implementation of the hierarchical scheduler,we have also developed a number of simple task schedulers.We present details of the implementation of Rate-Monotonic(RM) and Earliest Deadline First (EDF) schedulers. Finally,we present the design of our hierarchical schedulingframework, and we discuss our current status in the project.

  • 70.
    Behnam, Moris
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering.
    Sjödin, Mikael
    Mälardalen University, School of Innovation, Design and Engineering.
    Overrun Methods for Semi-Independent Real-Time Hierarchical Scheduling2009Report (Other academic)
    Abstract [en]

    The Hierarchical Scheduling Framework (HSF) has been introduced as a design-time framework to enable compositional schedulability analysis of embedded software systems with real-time properties. In this paper a software system consists of a number of semi-independent components called subsystems. Subsystems are developed independently and later integrated to form a system. To support this design process, in the paper, the proposed methods allow non-intrusive configuration and tuning of subsystem timing-behaviour via subsystem interfaces for selecting scheduling parameters. This paper considers three methods to handle overruns due to resource sharing between subsystems in the HSF. For each one of these three overrun methods corresponding scheduling algorithms The work in this paper is supported by the Swedish Foundation for Strategic Research (SSF), via the research programme PROGRESS. and associated schedulability analysis are presented together with analysis that shows under what circumstances one or the other is preferred. The analysis is generalized to allow for both Fixed Priority Scheduling (FPS) and Earliest Deadline First (EDF) scheduling. Also, a further contribution of the paper is the technique of calculating resource-holding times within the framework under different scheduling algorithms. The resource holding times being an important parameter in the global schedulability analysis.

  • 71.
    Behnam, Moris
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering.
    Sjödin, Mikael
    Mälardalen University, School of Innovation, Design and Engineering.
    Shin, Insik
    Department of Computer Science, KAIST University , Korea.
    Overrun Methods and Resource Holding Times for Hierarchical Scheduling of Semi-Independent Real-Time Systems2010In: IEEE Transactions on Industrial Informatics, ISSN 1551-3203, Vol. 6, no 1, p. 93-104Article in journal (Refereed)
    Abstract [en]

    The Hierarchical Scheduling Framework (HSF) has been introduced as a design-time framework toenable compositional schedulability analysis of embedded software systems with real-time properties. Inthis paper a software system consists of a number of semi-independent components called subsystems.Subsystems are developed independently and later integrated to form a system. To support this designprocess, in the paper, the proposed methods allow non-intrusive configuration and tuning of subsystemtiming-behaviour via subsystem interfaces for selecting scheduling parameters.This paper considers three methods to handle overruns due to resource sharing between subsystemsin the HSF. For each one of these three overrun methods corresponding scheduling algorithms and associatedschedulability analysis are presented together with analysis that shows under what circumstances one or the other is preferred. The analysis is generalized to allow for both Fixed Priority Scheduling (FPS)and Earliest Deadline First (EDF) scheduling. Also, a further contribution of the paper is the techniqueof calculating resource-holding times within the framework under different scheduling algorithms; theresource holding times being an important parameter in the global schedulability analysis.

  • 72.
    Behnam, Moris
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering.
    Åsberg, Mikael
    Mälardalen University, School of Innovation, Design and Engineering.
    Bril, Reinder
    Eindhoven University of Technology, The Netherlands.
    Overrun and Skipping in Hierarchically Scheduled Real-Time Systems2009In: 15th IEEE International Conference on Embedded and Real-Time Computing Systems and Applications, 2009, p. 519-526Conference paper (Refereed)
  • 73.
    Behnam, Moris
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering.
    Åsberg, Mikael
    Mälardalen University, School of Innovation, Design and Engineering.
    Shin, Insik
    Mälardalen University, School of Innovation, Design and Engineering.
    Synchronization protocols for hierarchical real-time scheduling frameworks2008In: Proceedings of the 1st Workshop on Compositional Theory and Technology for Real-Time Embedded Systems (CRTS'08) in conjunction with the 29th IEEE International Real-Time Systems Symposium (RTSS'08), Barcelona, Spain, 2008Conference paper (Refereed)
  • 74.
    Behnam, Moris
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Shin, Insik
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering.
    Nolin, Mikael
    Mälardalen University, School of Innovation, Design and Engineering.
    Scheduling of Semi-Independent Real-Time Components: Overrun Methods and Resource Holding Times2008In: Proceedings of the 13th IEEE International Conference on Emerging echnologies and Factory Automation (ETFA’08), 2008, p. 575-582Conference paper (Refereed)
    Abstract [en]

    The Hierarchical Scheduling Framework (HSF) has been introduced as a design-time framework enabling compositional schedulability analysis of embedded software systems with real-time properties. In this paper a system consists of a number of semi-independent components called subsystems. Subsystems are developed independently and later integrated to form a system. To support this design process, our proposed methods allow nonintrusive configuration and tuning of subsystem timing behaviour via subsystem interfaces for selecting scheduling parameters. This paper considers two methods to handle overruns due to resource sharing between subsystems in the HSF. We present the scheduling algorithms for overruns and their associated schedulability analysis, together with analysis that shows under what circumstances one or the other overrun method is preferred. Furthermore, we show how to calculate resource-holding times within our framework.

  • 75.
    Behnam, Moris
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Shin, Insik
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering.
    Nolin, Mikael
    Mälardalen University, School of Innovation, Design and Engineering.
    SIRAP: A Synchronization Protocol for Hierarchical Resource Sharing in Real-Time Open Systems2007In: EMSOFT'07: Proceedings of the Seventh ACM and IEEE International Conference on Embedded Software, 2007, p. 279-288Conference paper (Refereed)
    Abstract [en]

    This paper presents a protocol for resource sharing in a hierarchical real-time scheduling framework. Targeting real-time open systems, the protocol and the scheduling framework significantly reduce the efforts and errors associated with integrating multiple semi-independent subsystems on a single processor. Thus, our proposed techniques facilitate modern software development processes, where subsystems are developed by independent teams (or subcontractors) and at a later stage integrated into a single product. Using our solution, a subsystem need not know, and is not dependent on, the timing behaviour of other subsystems; even though they share mutually exclusive resources. In this paper we also prove the correctness of our approach and evaluate its efficiency.

  • 76.
    Behnam, Moris
    et al.
    Mälardalen University, Department of Computer Science and Electronics.
    Shin, Insik
    Mälardalen University, Department of Computer Science and Electronics.
    Nolte, Thomas
    Mälardalen University, Department of Computer Science and Electronics.
    Sjödin, Mikael
    Mälardalen University, Department of Computer Science and Electronics.
    Independent Abstraction and Dynamic Slack Reclaiming in Hierarchical Real-Time Open Systems2007In: Proceedings of the Work-In-Progress (WIP) session of the 19th Euromicro Conference on Real-Time Systems (ECRTS'07), Pisa, Italy, 2007, p. 1-4Conference paper (Refereed)
    Abstract [en]

    Independent subsystem abstraction allows subsystems to be developed and validated separately and supports an easier subsystem integration. In particular, this approach is desirable in open systems, since it does not require knowledge of temporal behaviour of other subsystems. However, independent

    abstraction, assuming the worst-case CPU supply pattern, requires extra CPU allocations. We present our work in progress on dynamic slack reclamation, which keeps track of such extra CPU allocations at run time. We are also investigating how to utilize those extra resources for supporting soft real-time tasks.

  • 77.
    Behnam, Moris
    et al.
    Mälardalen University, Department of Computer Science and Electronics.
    Shin, Insik
    Mälardalen University, Department of Computer Science and Electronics.
    Nolte, Thomas
    Mälardalen University, Department of Computer Science and Electronics.
    Sjödin, Mikael
    Mälardalen University, Department of Computer Science and Electronics.
    Real-Time Subsystem Integration in the Presence of Shared Resources2006In: Proceedings of the Work-In-Progress (WIP) session of the 27th IEEE Real-Time Systems Symposium (RTSS'06), Rio de Janeiro, Brazil: 27th IEEE International Real-Time Systems Symposium (RTSS 2006) Rio deJaneiro, Brazil, 5-8 December 2006, 2006Conference paper (Refereed)
    Abstract [en]

    We present our ongoing work to support the difficult, time consuming, and error-prone process of subsystem integration in the real-time domain. Our work will result in methods where independently developed subsystems, including both hard real-time and soft real-time functions, can be easily integrated without resulting unpredictable timing behaviour. The methods will also facilitate subsystem reuse, since a subsystem can easily be integrated in a new environment. Related research and methods are presented, together with our ongoing work in the area.

  • 78.
    Behnam, Moris
    et al.
    Mälardalen University, Department of Computer Science and Electronics.
    Shin, Insik
    Mälardalen University, Department of Computer Science and Electronics.
    Nolte, Thomas
    Mälardalen University, Department of Computer Science and Electronics.
    Sjödin, Mikael
    Mälardalen University, Department of Computer Science and Electronics.
    SIRAP: A Global Resource Sharing Protocol Facilitating Integration of Semi-independent Real-Time Systems2007Report (Other academic)
    Abstract [en]

    This paper presents a protocol for resource sharing in a hierarchical real-time scheduling framework. Together, the protocol and the scheduling framework significantly reduce the efforts and errors associated with integrating multiple semi-independent subsystems on a single processor. Thus, our proposed techniques facilitate modern software development processes, where subsystems are developed by independent teams (or subcontractors) and at a later stage integrated into a single product. Using our solution, a subsystem need not know, and is not dependent on, the timing behaviour of other subsystems; even though they share mutually exclusive resources. In this paper we also prove the correctness of our approach and evaluate its efficiency.

  • 79.
    Behnam, Moris
    et al.
    Mälardalen University, Department of Computer Science and Electronics.
    Shin, Insik
    Mälardalen University, Department of Computer Science and Electronics.
    Nolte, Tomas
    Mälardalen University, Department of Computer Science and Engineering.
    Nolin, Mikael
    Mälardalen University, Department of Computer Science and Electronics.
    An overrun method to support composition of semi-independent real-time components2008In: Proceedings - International Computer Software and Applications Conference, 2008, p. 1347-1352Conference paper (Refereed)
    Abstract [en]

    Engineers of embedded software systems rely on efficient design techniques and tools along with efficient run-time support. In the design of complex embedded real-time systems, the Hierarchical Scheduling Framework (HSF) has been introduced as a design-time framework enabling compositional schedulability analysis of embedded software systems with real-time properties. Moreover, the HSF provides a run-time framework guaranteeing that these non-functional requirements are met. In this paper a system consists of a number of semi-independent components called subsystems, and these subsystems are allowed to share logical resources. The HSF makes sure that the individual subsystems respect their allocated CPU budgets. However, as semi-independent sub-systems share logical resources, extra complexity is introduced. Specifically, the contribution of this paper is a novel method to allow for budget overruns; a common scenario when a subsystem utilizes shared logical resources. This proposed method is not only more resource efficient than existing methods, but it is also more appropriate for supporting composability of independently developed real-time subsystems.

  • 80.
    Benzi, Francesco
    et al.
    University of Pavia.
    Facchinetti, Tullio
    University of Pavia.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering.
    Almeida, Luis
    Universidade de Aveiro.
    Towards the Powerline Alternative in Automotive Applications2008In: Proceedings of the Work-In-Progress (WIP) session of the 7th IEEE International Workshop on Factory Communication Systems (WFCS'08), Dresden, Germany, 2008, p. 259-262Conference paper (Refereed)
    Abstract [en]

    The Power Line technology has received an increasing attention in the last decades due to its inherent benefits, mainly related to the reduction of cabling and associated costs. Power Line Communication (PLC) was first employed in power utilities and since the 80s in home automation, too. However, its use in the automotive field received relatively little attention. This paper revisits the related work in using PLC technology for communication within the automotive domain and outlines its possible benefits. Then, it focuses on the issues that need to be addressed when introducing the PLC in the automotive domain. The final goal of this work is to carry out a practical assessment of the PLC technology in the referred domain that may open the way for future use in industrial scale.

  • 81.
    Bohlin, markus
    et al.
    SICS.
    Lu, Yue
    Mälardalen University, School of Innovation, Design and Engineering.
    Kraft, Johan
    Mälardalen University, School of Innovation, Design and Engineering.
    Kreuger, Per
    SICS, Sweden.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering.
    Best-Effort Simulation-Based Timing Analysis using Hill-Climbing with Random Restarts2009In: In Proc. of RTCSA, Aug. 2009., 2009Conference paper (Refereed)
  • 82.
    Bohlin, Markus
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Lu, Yue
    Mälardalen University, School of Innovation, Design and Engineering.
    Kraft, Johan
    Mälardalen University, School of Innovation, Design and Engineering.
    Kreuger, Per
    Mälardalen University, School of Innovation, Design and Engineering.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering.
    Simulation-Based Timing Analysis of Complex Real-Time Systems2009In: 2009 15TH IEEE INTERNATIONAL CONFERENCE ON EMBEDDED AND REAL-TIME COMPUTING SYSTEMS AND APPLICATIONS, PROCEEDINGS, 2009, p. 321-328Conference paper (Refereed)
    Abstract [en]

    This paper presents an efficient best-effort approach for simulation-based timing analysis of complex real- time systems. The method can handle in principle any software design that can be simulated, and is based on controlling simulation input using a simple yet novel hill- climbing algorithm. Unlike previous approaches, the new algorithm directly manipulates simulation parameters such as execution times, arrival jitter and input. An evaluation is presented using six different simulation models, and two other simulation methods as reference: Monte Carlo simulation and MABERA. The new method proposed in this paper was 4-11% more accurate while at the same time 42 times faster, on average, than the reference methods.

  • 83.
    Bril, Reinder
    et al.
    Eindhoven University of Technology, The Netherlands.
    Keskin, Ugur
    Eindhoven University of Technology, The Netherlands.
    Behnam, Moris
    Mälardalen University, School of Innovation, Design and Engineering.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering.
    Schedulability analysis of synchronization protocols based on overrun without payback for hierarchical scheduling frameworks revisited2009Conference paper (Refereed)
  • 84.
    Danielsson, Jakob
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Ashjaei, Seyed Mohammad Hossein
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Behnam, Moris
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Sörensen, Thomas
    Westermo Teleindustri AB, Västerås, Sweden.
    Sjödin, Mikael
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Performance Evaluation of Network Convergence Time Measurement Techniques2017In: International Conference on Emerging Technologies And Factory Automation ETFA'17, 2017, p. 1-7Conference paper (Refereed)
    Abstract [en]

    In this paper we evaluate solutions that provide measurements for the network convergence time in switched Ethernet networks when links failures happen. We evaluate three solutions to measure the network convergence time in a faulty situation. Compared to the commercially available solutions, our proposals are cost-effective, portable, and open source. Thus, they are easy to deploy on many testbeds. We show the performance of the solutions by measuring different metrics including jitter, network convergence time and packet loss during the network recovery time. Our measurements indicate that it is possible to accurately measure the network convergence time using a packet sender which does not suffer interference from the overlying operating system. Furthermore, we noticed that the packet sniffer TShark did not suffer from kernel interrupts from overlying operating systems.

  • 85.
    Faragardi, H. R.
    et al.
    University of Innsbruck, Innsbruck, Austria.
    Vahabi, Maryam
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Fotouhi, Hossein
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Fahringer, T.
    University of Innsbruck, Innsbruck, Austria.
    An efficient placement of sinks and SDN controller nodes for optimizing the design cost of industrial IoT systems2018In: Software, practice & experience, ISSN 0038-0644, E-ISSN 1097-024X, Vol. 48, no 10, p. 1893-1919Article in journal (Refereed)
    Abstract [en]

    Recently, a growing trend has emerged toward using Internet of Things (IoT) in the context of industrial systems, which is referred to as industrial IoT. To deal with the time-critical requirements of industrial applications, it is necessary to consider reliability and timeliness during the design of an industrial IoT system. Through the separation of the control plane and the data plane, software-defined networking provides control units (controllers) coexisting with sink nodes, efficiently coping with network dynamics during run-time. It is of paramount importance to select a proper number of these devices (i.e., software-defined networking controllers and sink nodes) and locate them wisely in a network to reduce deployment cost. In this paper, we optimize the type and location of sinks and controllers in the network, subject to reliability and timeliness as the prominent performance requirements in time-critical IoT systems through ensuring that each sensor node is covered by a certain number of sinks and controllers. We propose PACSA-MSCP, an algorithm hybridizing a parallel version of the max-min ant system with simulated annealing for multiple-sink/controller placement. We evaluate the proposed algorithm through extensive experiments. The performance is compared against several well-known methods, and it is shown that our approach outperforms those methods by lowering the total deployment cost by up to 19%. Moreover, the deviation from the optimal solution achieved by CPLEX is shown to be less than 2.7%.

  • 86.
    Faragardi, Hamid Reza
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Dehnavi, Saed
    University of Tehran, Iran.
    Kargahi, Mehdi
    University of Tehran, Iran.
    Papadopoulos, Alessandro
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems. IS (Embedded Systems).
    A Time-Predictable Fog-Integrated Cloud Framework: One Step Forward in the Deployment of a Smart Factory2018In: CSI International Symposium on Real-Time and Embedded Systems and Technologies REST'18, 2018, p. 54-62Conference paper (Refereed)
    Abstract [en]

    This paper highlights cloud computing as one of the principal building blocks of a smart factory, providing a huge data storage space and a highly scalable computational capacity. The cloud computing system used in a smart factory should be time-predictable to be able to satisfy hard real-time requirements of various applications existing in manufacturing systems. Interleaving an intermediate computing layer-called fog-between the factory and the cloud data center is a promising solution to deal with latency requirements of hard real-time applications. In this paper, a time-predictable cloud framework is proposed which is able to satisfy end-to-end latency requirements in a smart factory. To propose such an industrial cloud framework, we not only use existing real-time technologies such as Industrial Ethernet and the Real-time XEN hypervisor, but we also discuss unaddressed challenges. Among the unaddressed challenges, the partitioning of a given workload between the fog and the cloud is targeted. Addressing the partitioning problem not only provides a resource provisioning mechanism, but it also gives us a prominent design decision specifying how much computing resource is required to develop the fog platform, and how large should the minimum communication bandwidth be between the fog and the cloud data center.

  • 87.
    Faragardi, Hamid Reza
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Dehnavi, Saed
    University of Tehran, Iran.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Kargahi, Mehdi
    An Energy-Aware Time-Predictable Cloud Data CenterIn: Software, practice & experience, ISSN 0038-0644, E-ISSN 1097-024XArticle in journal (Refereed)
  • 88.
    Faragardi, Hamid Reza
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems. Univ Innsbruck, Innsbruck, Austria.
    Dehnavi, Saeid
    Univ Tehran, Sch Elect & Comp Engn, Coll Engn, Tehran, Iran..
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Kargahi, Mehdi
    Univ Tehran, Sch Elect & Comp Engn, Coll Engn, Tehran, Iran.;Inst Res Fundamental Sci IPM, Sch Comp Sci, Tehran, Iran..
    Fahringer, Thomas
    Univ Innsbruck, Inst Comp Sci, Distributed & Parallel Syst Grp, Innsbruck, Austria.
    An energy-aware resource provisioning scheme for real-time applications in a cloud data center2018In: Software, practice & experience, ISSN 0038-0644, E-ISSN 1097-024X, Vol. 48, no 10, p. 1734-1757Article in journal (Refereed)
    Abstract [en]

    Based on a pay-as-you-go model, cloud computing provides the possibility of hosting pervasive applications from both academic and business domains. However, data centers hosting cloud applications consume huge amounts of electrical energy, contributing to high operational costs and large carbon footprints to the environment. Energy-aware resource provisioning is an effective solution to diminish the energy consumption of cloud data centers. Recently, a growing trend has emerged, where cloud technology is used to run periodic real-time applications such as multimedia, telecommunication, video gaming, and industrial applications. In order for a real-time application to be able to use cloud services, cloud providers have to be able to provide timing guarantees. In this paper, we introduce an energy-aware resource provisioning mechanism for cloud data centers, which are capable of serving real-time periodic tasks following the Software as a Service model. The proposed method is compared against an energy-aware version of the RT-OpenStack. RT-OpenStack is a recently proposed approach to provide a time-predictable version of OpenStack. The experimental results manifest that our proposed resource provisioning method outperforms energy-aware version of the RT-OpenStack by 16.01%, 25.45%, and 25.45% in terms of energy consumption, number of used servers, and average utilization of used servers, respectively. Moreover, from the scalability perspective, the preference of the proposed method for large-scale data centers is more considerable.

  • 89.
    Faragardi, Hamid Reza
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Fotouhi, Hossein
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Rahmani, Rahim
    Stockholm University, Stockholm, Sweden.
    A Cost Efficient Design of a Multi-Sink Multi-ControllerWSN in a Smart Factory2017In: Proceedings - 2017 IEEE 19th Intl Conference on High Performance Computing and Communications, HPCC 2017, 2017 IEEE 15th Intl Conference on Smart City, SmartCity 2017 and 2017 IEEE 3rd Intl Conference on Data Science and Systems, DSS 2017, 2017, p. 594-602Conference paper (Refereed)
    Abstract [en]

    Internet of Things (IoT), one of the key elementsof a smart factory, is dubbed as Industrial IoT (IIoT). Softwaredefined networking is a technique that benefits network managementin IIoT applications by providing network reconfigurability.In this way, controllers are integrated within the networkto advertise routing rules dynamically based on network andlink changes. We consider controllers within Wireless SensorNetworks (WSNs) for IIoT applications in such a way to providereliability and timeliness. Network reliability is addressed for thecase of node failure by considering multiple sinks and multiplecontrollers. Real-time requirements are implicitly applied bylimiting the number of hops (maximum path-length) betweensensors and sinks/controllers, and by confining the maximumworkload on each sink/controller. Deployment planning of sinksshould ensure that when a sink or controller fails, the networkis still connected. In this paper, we target the challenge ofplacement of multiple sinks and controllers, while ensuring thateach sensor node is covered by multiple sinks (k sinks) andmultiple controllers (k' controllers). We evaluate the proposedalgorithm using the benchmark GRASP-MSP through extensiveexperiments, and show that our approach outperforms thebenchmark by lowering the total deployment cost by up to24%. The reduction of the total deployment cost is fulfilled notonly as the result of decreasing the number of required sinksand controllers but also selecting cost-effective sinks/controllersamong all candidate sinks/controllers.

  • 90.
    Faragardi, Hamid Reza
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Lisper, Björn
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Towards a Communication-efficient Mapping of AUTOSAR Runnables on Multi-cores2013Conference paper (Refereed)
    Abstract [en]

    Multi-core technology is recognized as a key component to develop new cost-efficient products. It can lead to reduction of the overall hardware cost through hardware consolidation. However, it also results in tremendous challenges related to the combination of predictability and performance. The AUTOSAR consortium has developed as the worldwide standard for automotive embedded software systems. One of the prominent aspects of this consortium is to support multi-core systems. In this paper, the ongoing work on addressing the challenge of achieving a resource efficient and predictable mapping of AUTOSAR runnables onto a multi-core system is discussed. The goal is to minimize the runnables’ communication cost besides meeting timing and precedence constraints of the runnables. The basic notion utilized in this research is to consider runnable granularity, which leads to an increased flexibility in allocating runnables to various cores, compared of task granularity in which all of the runnables hosted on a task should be allocated on the same core. This increased flexibility can potentially enhance communication cost. In addition, a heuristic algorithm is introduced to create a task set according to the mapping of runnables on the cores. In our current work, we are formulating the problem as an Integer Linear Programming (ILP). Therefore, conventional ILP solvers can be easily applied to derive a solution.

  • 91.
    Faragardi, Hamid Reza
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Lisper, Björn
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Sandström, K.
    ABB Corporate Research, Västeräs, Sweden.
    Nolte, Thomas
    ABB Corporate Research, Västerås, Sweden.
    A communication-aware solution framework for mapping AUTOSAR runnables on multi-core systems2014In: 19th IEEE International Conference on Emerging Technologies and Factory Automation, ETFA 2014, 2014, p. Article number 7005244-Conference paper (Refereed)
    Abstract [en]

    An AUTOSAR-based software application contains a set of software components, each of which encapsulates a set of runnable entities. In fact, the mission of the system is fulfilled as result of the collaboration between the runnables. Several trends have recently emerged to utilize multi-core technology to run AUTOSAR-based software. Not only the overhead of communication between the runnables is one of the major performance bottlenecks in multi-core processors but it is also the main source of unpredictability in the system. Appropriate mapping of the runnables onto a set of tasks (called mapping process) along with proper allocation of the tasks to processing cores (called task allocation process) can significantly reduce the communication overhead. In this paper, three solutions are suggested, each of which comprises both the mapping and the allocation processes. The goal is to maximize key performance aspects by reducing the overall inter-runnable communication time besides satisfying given timing and precedence constraints. A large number of randomly generated experiments are carried out to demonstrate the efficiency of the proposed solutions.

  • 92.
    Faragardi, Hamid Reza
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Lisper, Björn
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Sandström, Kristian
    RISE SICS, Västerås, Sweden.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    A resource efficient framework to run automotive embedded software on multi-core ECUs2018In: Journal of Systems and Software, ISSN 0164-1212, E-ISSN 1873-1228, p. 64-83Article in journal (Refereed)
    Abstract [en]

    The increasing functionality and complexity of automotive applications requires not only the use of more powerful hardware, e.g., multi-core processors, but also efficient methods and tools to support design decisions. Component-based software engineering proved to be a promising solution for managing software complexity and allowing for reuse. However, there are several challenges inherent in the intersection of resource efficiency and predictability of multi-core processors when it comes to running component-based embedded software. In this paper, we present a software design framework addressing these challenges. The framework includes both mapping of software components onto executable tasks, and the partitioning of the generated task set onto the cores of a multi-core processor. This paper aims at enhancing resource efficiency by optimizing the software design with respect to: 1) the inter-software-components communication cost, 2) the cost of synchronization among dependent transactions of software components, and 3) the interaction of software components with the basic software services. An engine management system, one of the most complex automotive sub-systems, is considered as a use case, and the experimental results show a reduction of up to 11.2% total CPU usage on aquad-core processor, in comparison with the common framework in the literature. 

  • 93.
    Faragardi, Hamid Reza
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Lisper, Björn
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Sandström, Kristian
    ABB Corp. Research, Vasterås, Sweden.
    Nolte, Thomas
    ABB Corp. Research, Vasterås, Sweden.
    An efficient scheduling of AUTOSAR runnables to minimize communication cost in multi-core systems2014In: 2014 7th International Symposium on Telecommunications, IST 2014, 2014, p. 41-48Conference paper (Refereed)
    Abstract [en]

    The AUTOSAR consortium has developed as the worldwide standard for automotive embedded software systems. From a processor perspective, AUTOSAR was originally developed for single-core processor platforms. Recent trends have raised the desire for using multi-core processors to run AUTOSAR software. However, there are several challenges in reaching a highly efficient and predictable design of AUTOSAR-based embedded software on multi-core processors. In this paper a solution framework comprising both the mapping of runnables onto a set of tasks and the scheduling of the generated task set on a multi-core processor is suggested. The goal of the work presented in this paper is to minimize the overall inter-runnable communication cost besides meeting all corresponding timing and precedence constraints. The proposed solution framework is evaluated and compared with an exhaustive method to demonstrate the convergence to an optimal solution. Since the exhaustive method is not applicable for large size instances of the problem, the proposed framework is also compared with a well-known meta-heuristic algorithm to substantiate the capability of the frameworks to scale up. The experimental results clearly demonstrate high efficiency of the solution in terms of both communication cost and average processor utilization.

  • 94.
    Faragardi, Hamid Reza
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Rajabi, A.
    School of ECE, University of Tehran, Iran.
    Sandstrom, Kristian
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    EAICA: An energy-aware resource provisioning algorithm for Real-Time Cloud services2016In: IEEE International Conference on Emerging Technologies and Factory Automation, ETFA, 2016Conference paper (Refereed)
    Abstract [en]

    Cloud computing is receiving an increasing attention when it comes to providing a wide range of cost-effective services. In this context, energy consumption of communication and computing resources contribute to a major portion of the cost of services. On the other hand, growing energy consumption not only results in a higher operational cost, but it also causes negative environmental impacts. A large number of cloud applications in, e.g., telecommunication, multimedia, and video gaming, have real-time requirements. A cloud computing system hosting such applications, that requires a strict timing guarantee for its provided services, is denoted a Real-Time Cloud (RTC). Minimizing energy consumption in a RTC is a complicated task as common methods that are used for decreasing energy consumption can potentially lead to timing violations. In this paper, we present an online energy-aware resource provisioning framework to reduce the deadline miss ratio for real-time cloud services. The proposed provisioning framework not only considers the energy consumption of servers but it also takes the energy consumption of the communication network into account, to provide a holistic solution. An extensive range of simulation results, based on real data, show a noticeable improvement regarding energy consumption while keeping the number of timing violations less than 1% in average.

  • 95.
    Faragardi, Hamid Reza
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Rajabi, A.
    School of Electrical and Computer Engineering, University of Tehran, Tehran, Iran .
    Shojaee, R.
    School of Electrical and Computer Engineering, University of Tehran, Tehran, Iran .
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Towards energy-aware resource scheduling to maximize reliability in cloud computing systems2013In: Proc. - IEEE Int. Conf. High Perform. Comput. Commun., HPCC IEEE Int. Conf. Embedded Ubiquitous Comput., EUC, 2013, p. 1469-1479Conference paper (Refereed)
    Abstract [en]

    Cloud computing has become increasingly popular due to deployment of cloud solutions that will enable enterprises to cost reduction and more operational flexibility. Reliability is a key metric for assessing performance in such systems. Fault tolerance methods are extensively used to enhance reliability in Cloud Computing Systems (CCS). However, these methods impose extra hardware and/or software cost. Proper resource allocation is an alternative approach which can significantly improve system reliability without any extra overhead. On the other hand, contemplating reliability irrespective of energy consumption and Quality of Service (QoS) requirements is not desirable in CCSs. In this paper, an analytical model to analyze system reliability besides energy consumption and QoS requirements is introduced. Based on the proposed model, a new online resource allocation algorithm to find the right compromise between system reliability and energy consumption while satisfying QoS requirements is suggested. The algorithm is a new swarm intelligence technique based on imperialist competition which elaborately combines the strengths of some well-known meta-heuristic algorithms with an effective fast local search. A wide range of simulation results, based on real data, clearly demonstrate high efficiency of the proposed algorithm. 

  • 96.
    Faragardi, Hamid Reza
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Rajabi, Aboozar
    University of Tehran, Tehran, Iran.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Heidarizadeh, Amir Hosein
    A Profit-aware Allocation of High Performance Computing Applications on Distributed Cloud Data Centers with Environmental Considerations2014In: CSI Journal on Computer Science and Engineering JCSE, Vol. 2, no 1, p. 28-38Article in journal (Refereed)
    Abstract [en]

    A Set of Geographically Distributed Cloud data centers (SGDC) is a promising platform to run a large number of High Performance Computing Applications (HPCAs) in a cost-efficient manner. Energy consumption is a key factor affecting the profit of a cloud provider. In a SGDC, as the data centers are located in different corners of the world, the cost of energy consumption and the amount of CO2 emission significantly vary among the data centers. Therefore, in such systems not only a proper allocation of HPCAs results in CO2 emission reduction, but it also causes a substantial increase of the provider's profit. Furthermore, CO2 emission reduction mitigates the destructive environmental impacts. In this paper, the problem of allocation of a set of HPCAs on a SGDC is discussed where a two-level allocation framework is introduced to deal with the problem. The proposed framework is able to reach a good compromise between CO2 emission and the providers' profit subject to satisfy HPCAs deadlines and memory constraints. Simulation results based on a real intensive workload demonstrate that the proposed framework enhances the CO2 emission by 17% and the provider's profit by 9% in average.

  • 97.
    Faragardi, Hamid Reza
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Rajabi, Aboozar
    University of Tehran, Tehran, Iran.
    Shojaee, Reza
    University of Tehran, Tehran, Iran.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering.
    Towards Energy-Aware Resource Scheduling to Maximize Reliability in Cloud Computing Systems2013Conference paper (Refereed)
    Abstract [en]

    Cloud computing has become increasingly popular due to deployment of cloud solutions that will enable enterprises to cost reduction and more operational flexibility. Reliability is a key metric for assessing performance in such systems. Fault tolerance methods are extensively used to enhance reliability in Cloud Computing Systems (CCS). However, these methods impose extra hardware and/or software cost. Proper resource allocation is an alternative approach which can significantly improve system reliability without any extra overhead. On the other hand, contemplating reliability irrespective of energy consumption and Quality of Service (QoS) requirements is not desirable in CCSs. In this paper, an analytical model to analyze system reliability besides energy consumption and QoS requirements is introduced. Based on the proposed model a new online resource allocation algorithm to find the right compromise between system reliability and energy consumption while satisfies QoS requirement is suggested. The algorithm is a new swarm intelligence technique based on imperialist competition which elaborately combines the strengths of some well-known meta-heuristic algorithms with an effective fast local search. A wide range of simulation results, based on real data clearly demonstrate high efficiency of the proposed algorithm.

  • 98.
    Fredriksson, Johan
    et al.
    Mälardalen University, Department of Computer Science and Electronics.
    Nolte, Thomas
    Mälardalen University, Department of Computer Science and Electronics.
    Ermedahl, Andreas
    Mälardalen University, Department of Computer Science and Electronics.
    Nolin, Mikael
    Mälardalen University, Department of Computer Science and Electronics.
    Clustering Worst-Case Execution Times for Software Components2007In: Proceedings of the 7th International Workshop on Worst Case Execution Time Analysis (WCET'07), Pisa, Italy, 2007, p. 19-25Conference paper (Refereed)
    Abstract [en]

    For component-based systems, classical techniques for WCET-estimation produce unacceptable overestimations of the WCET. This is because software components have more general behavior in order to support reuse. Existing tools and methods for component-based software engineering (CBSE) do not yet adequately consider reusable analyses.

    We present a method that allows different WCETs to be associated with subsets of the component behavior by clustering WCETs with respect to behavior. The method is intended to be used for facilitating reusable WCET analysis for reusable software components. We illustrate our technique and demonstrate its potential in achieving tight WCET-estimates for components with rich behavior.

  • 99.
    Fredriksson, Johan
    et al.
    Mälardalen University, Department of Computer Science and Electronics.
    Nolte, Thomas
    Mälardalen University, Department of Computer Science and Electronics.
    Ermedahl, Andreas
    Mälardalen University, Department of Computer Science and Electronics.
    Sjödin, Mikael
    Mälardalen University, Department of Computer Science and Electronics.
    Contract-Based Reusable Analysis for Software Components with Extra-Functional Properties2007In: Proceedings of the Work-In-Progress (WIP) session of the 19th Euromicro Conference on Real-Time Systems (ECRTS'07), Pisa, Italy, 2007, p. 57-60Conference paper (Refereed)
    Abstract [en]

    Component-based software engineering (CBSE) for embedded systems is currently gaining ground because of shortened time-to-market, reduced development costs and increased software quality. One main characteristic of CBSE that enable these benefits is its facilitation of component reuse. However, existing tools and methods do not consider reuse of extra-functional properties in these systems.

    In this paper we extend our previous work on contract-based reusable execution time predictions for software components with additional extra-functional properties, such as memory and energy consumption.

  • 100.
    Fredriksson, Johan
    et al.
    Mälardalen University, Department of Computer Science and Electronics.
    Nolte, Thomas
    Mälardalen University, Department of Computer Science and Electronics.
    Ermedahl, Andreas
    Mälardalen University, Department of Computer Science and Electronics.
    Sjödin, Mikael
    Mälardalen University, Department of Computer Science and Electronics.
    Worst-Case Execution Time Clustering for Software Components2007Report (Other academic)
    Abstract [en]

    For component-based systems, classical techniques for WCET-estimation produce unacceptable overestimations of the WCET. This is because software components have more general behavior in order to support reuse. Existing tools and methods for component-based software engineering (CBSE) do not yet adequately consider reusable analyses. We present a method that allows different WCETs to be associated with subsets of the component behavior by clustering WCETs with respect to behavior. The method is intended to be used for facilitating reusable WCET analysis for reusable software components. We illustrate our technique and demonstrate its potential in achieving tight WCET-estimates for components with rich behavior.

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