| 11. |
- Afshar, Sara, et al.
(författare)
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Semi-partitioning under a Blocking-Aware Task Allocation
- 2015
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Ingår i: Proceedings - Real-Time Systems Symposium. - 9781467395076 ; , s. 379-379
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Konferensbidrag (refereegranskat)abstract
- Semi-partitioned scheduling is a resource efficient scheduling approach compared to the conventional multiprocessor scheduling approaches in terms of system utilization and migration overhead. Semi-partitioned scheduling can better utilize processor bandwidth compared to the partitioned scheduling while introducing less overhead compared to the global scheduling. Various techniques have been proposed to schedule tasks in a semi-partitioned environment, however, they have used blockingagnostic allocation mechanisms in presence of resource sharing protocols. Since, the allocation mechanism can highly affect the system schedulability, in this paper we provide a blocking-aware allocation mechanism for semi-partitioned scheduling framework under a suspension-based resource sharing protocol. We have applied new heuristics for sorting the tasks in the algorithm that shows improvements upon system schedulability. Finally, we present our preliminary results.
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| 12. |
- Afshar, Sara Zargari, et al.
(författare)
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An optimal spin-lock priority assignment algorithm for real-time multi-core systems
- 2017
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Ingår i: The 23th IEEE International Conference on Embedded and Real-Time Computing Systems and Applications RTCSA'17.
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Konferensbidrag (refereegranskat)abstract
- Support for exclusive access to shared (global) resources is instrumental in the context of embedded real-time multi-core systems, and mechanisms for achieving such access must be deterministic and efficient. There exist two traditional approaches for multiprocessors when a task requests a global resource that is locked by a task on a remote core: a spin-based approach, i.e. non-preemptive busy waiting for the resource to become available, and a suspension-based approach, i.e. the task relinquishes the processor. A suspension-based approach can be viewed as a spin-based approach where the lowest priority on a core is used during spinning, similar to a non-preemptive spin-based approach where the highest priority on a core is used. By taking such a view, we previously provided a general model for spinning, where any arbitrary priority can be used for spinning, i.e. from the lowest to the highest priority on a core. Targeting partitioned fixed-priority preemptive scheduled multiprocessors and spin-based approaches that use a fixed priority for spinning per core for all tasks, we aim at increasing the schedulability of multiprocessor systems by using the spin-lock priority per core as parameter. In this paper, we present (i) a generalization of the traditional worst-case response-time analysis for non-preemptive spin-based approaches addressing an arbitrary but fixed spin-lock priority per core, (ii) an optimal spin-lock priority assignment (OSPA) algorithm per core, i.e. an algorithm that will find a fixed spin-lock priority per core that will make the system schedulable, whenever such an assignment exists and, (iii) comparative evaluations of the OSPA algorithm with the spin-based and suspension-based approaches where OSPA showed up to 38% improvement compared to both approaches.
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| 13. |
- Aglianò, Simone, et al.
(författare)
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Resource Management and Control in Virtualized SDN Networks
- 2018
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Ingår i: CSI International Symposium on Real-Time and Embedded Systems and Technologies REST'18. - 9781538614754 ; , s. 47-53
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Konferensbidrag (refereegranskat)abstract
- Software defined networking and network virtual-ization are widely considered promising techniques for reducing the complexity of network management in many contexts that require high Quality of Service (QoS) and the support for heterogeneous architectures. In this paper we address a network architecture, here called a virtualized SDN network, that combines the benefits of SDN and virtualization. To cope with the demand for efficiently sharing a platform among several services, here a resource management mechanism to reserve and control network resources among various services in the virtualized SDN networks is proposed. The mechanism is implemented on an SDN controller and a set of experiments show the effectiveness of the proposed approach.
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| 14. |
- Al-Dulaimy, Auday, et al.
(författare)
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Fault Tolerance in Cloud Manufacturing : An Overview
- 2023
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Ingår i: Lecture Notes of the Institute for Computer Sciences, Social-Informatics and Telecommunications Engineering, LNICST. - : Springer Science and Business Media Deutschland GmbH. - 9783031318900 ; , s. 89-101
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Konferensbidrag (refereegranskat)abstract
- Utilizing edge and cloud computing to empower the profitability of manufacturing is drastically increasing in modern industries. As a result of that, several challenges have raised over the years that essentially require urgent attention. Among these, coping with different faults in edge and cloud computing and recovering from permanent and temporary faults became prominent issues to be solved. In this paper, we focus on the challenges of applying fault tolerance techniques on edge and cloud computing in the context of manufacturing and we investigate the current state of the proposed approaches by categorizing them into several groups. Moreover, we identify critical gaps in the research domain as open research directions. © 2023, ICST Institute for Computer Sciences, Social Informatics and Telecommunications Engineering.
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| 15. |
- Almeida, Luis, et al.
(författare)
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Managing end-to-end resource reservations
- 2014
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Ingår i: 7th International Workshop on Compositional Theory and Technology for Real-Time Embedded Systems CRTS'14.
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Konferensbidrag (refereegranskat)
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| 16. |
- Ashjaei, Mohammad, et al.
(författare)
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A Compact Approach to Clustered Master-Slave Ethernet Networks
- 2012
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Ingår i: IEEE International Workshop on Factory Communication Systems - Proceedings, WFCS. - 9781467315739 ; , s. 157-160
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Konferensbidrag (refereegranskat)abstract
- Ethernet switches are increasingly used in real-time distributed systems as a technical solution to guarantee the timeliness in communications. However, there are still limitations related to real-time behavior caused by the limited number of priority levels and the possibility of memory overruns with consequent message losses. These limitations can be eliminated using a master/slave technique such as proposed by the FTT paradigm. This led to the FTT-SE protocol that schedules transmissions centrally in a master node. While this protocol has already been well studied and investigated for small networks with a single switch, its extension to larger networks is still an open issue. In this paper we propose a compact clustered solution to scale the FTT-SE protocol to networks of multiple switches by organizing the network in sub-networks composed of one master and one switch each and which can be connected directly, without bridges. This paper also shows how the timeliness of the traffic can still be enforced. The validation is currently on-going.
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| 17. |
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| 18. |
- Ashjaei, Mohammad, et al.
(författare)
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Dynamic reconfiguration in HaRTES switched ethernet networks
- 2016
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Ingår i: IEEE International Workshop on Factory Communication Systems - Proceedings, WFCS. - 9781509023394
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Konferensbidrag (refereegranskat)abstract
- The ability of reconfiguring a system during runtime is essential for dynamic real-time applications in which resource usage is traded online for quality of service. The HaRTES switch, which is a modified Ethernet switch, holds this ability for the network resource, and at the same time it provides hard real-time support for both periodic and sporadic traffic. Although the HaRTES switch technologically caters this ability, a protocol to actually perform the dynamic reconfiguration is missing in multi-hop HaRTES networks. In this paper we introduce such a protocol that is compatible with the traffic scheduling method used in the architecture. We prove the correctness of the protocol using a model checking technique. Moreover, we conduct a set of simulation experiments to show the performance of the protocol and we also show that the reconfiguration process is terminated within a bounded time.
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| 19. |
- Ashjaei, Mohammad, et al.
(författare)
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Dynamic Reconfiguration in Multi-Hop Switched Ethernet Networks
- 2014
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Ingår i: ACM SIGBED Review. Special Issue on 6th Workshop on Adaptive and Reconfigurable Embedded Systems (APRES 2014). - : Association for Computing Machinery (ACM). - 1551-3688. ; 11:3, s. 62-65
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Tidskriftsartikel (refereegranskat)abstract
- The FTT-SE protocol provides adaptive real-time communication on Ethernet networks. To assure a continued real-time behavior, FTT-SE integrates admission control with a quality-of-service mechanism, which screen all adaptation and reconfiguration requests, accepting only those that do not compromise the system timeliness. The adaptability and reconfigurability have been deeply studied in the case of single switch FTT-SE architectures, whereas the extension of that for the multi-hop FTT-SE architecture was not yet investigated. Therefore, in this paper we study the challenges of enabling dynamic reconfiguration in multi-hop FTT-SE networks, we propose two methods (one centralized and one distributed) and we present a qualitative comparison between them.
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| 20. |
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