Hierarchical scheduling frameworks have lately received a lot of attention for component-based design of complex real-timesystems. the specification of the resource reservation policy play a dominant role in such fra...
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ISBN:
(纸本)0769526764
Hierarchical scheduling frameworks have lately received a lot of attention for component-based design of complex real-timesystems. the specification of the resource reservation policy play a dominant role in such frameworks. In this context, the notion of real-time virtual resources results a very flexible representation of resource reservation schemes. We intend to combine the advantages offered by virtual resource scheduling with very general event models specified using real-time calculus. Our proposed framework permits resource partitioning to be extended to multiple levels and handles a wider range of scheduling algorithms and task models. In addition, it allows the handling of data dependencies between tasks from different task groups in the hierarchy.
Functional safety is aimed at avoiding unacceptable risks and safety damages due to system functional failures, and it is a critical demand for the automotive embeddedsystems. For safety-critical distributed automoti...
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ISBN:
(纸本)9781538637906
Functional safety is aimed at avoiding unacceptable risks and safety damages due to system functional failures, and it is a critical demand for the automotive embeddedsystems. For safety-critical distributed automotive functions, reliability is an important functional safety requirement and reliability goal should be assured. In general, the key of reliability goal assurance method is to transfer the reliability goal of a distributed function to that of each task. this study proposes an effective reliability goal assurance method called RGAGM for automotive functional safety. the core idea of this method is defining two kinds of geometric mean for tasks and function, respectively, and preassigning geometric mean-based reliability values for unassigned tasks, thereby saving more resources for systems. the correctness of the proposed RGAGM method is proved. Experiment results on the real-life automotive function and the randomly generated distributed automotive functions show that the proposed method can effectively ensure the reliability goal and reduce resource consumption cost compared withthe stateof-the-art MRCRG method.
In this paper, we study the problem of scheduling periodic task sets defined under Quality of Service (QoS) constraints. In our approach, periodic tasks allow occasional skips of instances. A new algorithm, called RLP...
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ISBN:
(纸本)0769523463
In this paper, we study the problem of scheduling periodic task sets defined under Quality of Service (QoS) constraints. In our approach, periodic tasks allow occasional skips of instances. A new algorithm, called RLP (Red tasks as Late as Possible) based on the Skip-Over model and the EDL (Earliest Deadline as Late as Possible) scheduling strategy, is proposed to enhance the QoS observed for periodic tasks, i.e, the ratio of periodic tasks which complete before their deadline. We prove that our results are never worse than those obtained in previous work. Experimental results also show significant improvement achieved by our algorithm over RTO and BWP.
Energy management is becoming an increasingly important problem in application domains ranging from embedded devices to data centers. In many such systems, multi-core processors are projected as a promising technology...
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ISBN:
(纸本)9780769545028
Energy management is becoming an increasingly important problem in application domains ranging from embedded devices to data centers. In many such systems, multi-core processors are projected as a promising technology to achieve improved performance with a lower power envelope. Managing the application power consumption under timing constraints poses significant challenges in these emerging platforms. In this paper, we study the energy-efficient scheduling of periodic realtime tasks with implicit deadlines on chip multi-core processors (CMPs). We specifically consider processors with a single voltage and clock frequency domain, such as the state-of-the-art embedded multi-core NVIDIA Tegra 2 processor and enterprise-class processors such as Intel's Itanium 2, i5, i7 and IBM's Power 6 and Power 7 series. the major contributions of this work are (i) we prove that Worst-Fit-Decreasing (WFD) task partitioning when Rate-Monotonic Scheduling (RMS) is used has an approximation ratio of 1.71 for the problem of minimizing the schedulable operating frequency with partitioned fixed-priority scheduling, (ii) we illustrate the major shortcoming of WFD with RMS resulting from not considering task periods during allocation, and (iii) we propose a Single-clock domain multi-processor Frequency Assignment Algorithm (SFAA) that determines a globally energy-efficient frequency while including task period relationships. Our evaluation results show that SFAA provides significant energy gains when compared to WFD. In fact SFAA is shown to save up to 55% more power compared to WFD for an octa-core processor.
Under limited parallelism, processes competing for a single processor may issue at any time operations on remote co-processors, during which the processor is not idled but granted to other ready processes instead. We ...
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ISBN:
(纸本)0769523463
Under limited parallelism, processes competing for a single processor may issue at any time operations on remote co-processors, during which the processor is not idled but granted to other ready processes instead. We reduce the pessimism in existing Worst-case Response time (WCRT) analysis for such systems by examining temporal patterns of local/remote execution. We extend to multi-CPU variants of the model and offer a WCRT-based feasibility test for Symmetric Multiprocessor (SMP) systems.
. the real-time implementation of a controller typically introduces artefacts like delay and jitters that have not been considered at the design stage. As a consequence, the system behaves in a non-periodic manner, an...
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ISBN:
(纸本)0769526764
. the real-time implementation of a controller typically introduces artefacts like delay and jitters that have not been considered at the design stage. As a consequence, the system behaves in a non-periodic manner, and the real performance is degraded with respect to the expected response. this paper proposes a hybrid task model to reduce the impact of the scheduling on the control performance. For a large batch of typical plants, we analyze how sensitive the control system is to jitter when the sampling rate is slow or fast compared to the bandwidth of the system.
real-timesystems could be modeled using AOP based on UML. Timing requirements could be separated from the system according the separation of concerns techniques, expressed as a time-aspect independence of the system,...
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ISBN:
(纸本)0769523463
real-timesystems could be modeled using AOP based on UML. Timing requirements could be separated from the system according the separation of concerns techniques, expressed as a time-aspect independence of the system, and designed occurrence. So a timing model could be created to describe the time of the system. Finally the timing model could be woven into the system to compose a real-time system based on the AOP technology only when needed for a particular application. Also UML had been extended to express AOP and the time model. the real-timesystems could be modeled from the static structure, dynamic behaviors and weaving of the time-aspect, and an elevator case had been given as an example.
We consider a resource synthesis technique for real-timesystems where dynamic voltage scaling is supported, the energy budget is limited, and the performance of the system depends on how resources and energy are used...
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ISBN:
(纸本)9780769529752
We consider a resource synthesis technique for real-timesystems where dynamic voltage scaling is supported, the energy budget is limited, and the performance of the system depends on how resources and energy are used We propose a resource synthesis technique that derives boththe supply voltages and the resource allocation of the tasks in the system to maximize system performance. the resulting system satisfies real-time schedulability and energy requirements.
timeliness and accuracy are two major concerns in many real-timeembeddedsystems working in dynamic environments. It has been emphasized in the literature that in various real-timeapplications such as control system...
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In this paper we analyze the influence of the urgency in the timed transitions, and as consequence, in the test suite generation. As result, we formalize rules to generate sequences where the messages exchanged may be...
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ISBN:
(纸本)9780769529752
In this paper we analyze the influence of the urgency in the timed transitions, and as consequence, in the test suite generation. As result, we formalize rules to generate sequences where the messages exchanged may be instantaneous or delayed. In addition, the generated scenarios are able to detect timing faults. For test generation, we use a prototype tool called HJ2IF It is based on a test purpose algorithm, called Hit-or-Jump and it is applied for systems specified using Intermediate Format language (IF).
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