| 1. |
- Afshar, Sara, et al.
(författare)
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Integrating independently developed real-time applications on a shared multi-core architecture
- 2012
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Ingår i: 5th International Workshop on Compositional Theory and Technology for Real-Time Embedded Systems (CRTS'12). - San Juan, Puerto Rico.
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Konferensbidrag (refereegranskat)abstract
- The shift towards multi-core platforms has become inevitable from an industry perspective, therefore proper techniques are needed to deal with challenges related to this migration from single core architectures to a multi-core architecture. One of the main concerns for the system developers in this context is the migration of legacy real-time systems to multi-core architectures. To address this concern and to simplify migration, independently developed subsystems are abstracted with an interface, such that when working with multiple independently-developed subsystems to be integrated on a shared platform, one does not need to be aware of information or policies used in other subsystems in order to determine subsystem-level schedulability. Instead schedulability can be checked through their interfaces at the time of integration on a shared multi-core architecture. In this paper we propose a solution for the case where some of the independently-developed subsystems are distributed over more than one processor and we propose an approach to generate interfaces of subsystems that may share mutually exclusive resources.
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| 2. |
- Afshar, Sara, et al.
(författare)
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Resource Sharing under Multiprocessor Semi-Partitioned Scheduling
- 2012
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Ingår i: 18th IEEE International Conference on Embedded and Real-Time Computing Systems and Applications (RTCSA'12). - 978-1-4673-3017-6 ; s. 290-299
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Konferensbidrag (refereegranskat)abstract
- Semi-partitioned scheduling has become the subject of recent interest for multiprocessors due to better utilization results, compared to conventional global and partitioned scheduling algorithms. Under semi-partitioned scheduling, a major group of tasks are assigned to fixed processors while a low number of tasks are allocated to more than one processor. Various task assigning techniques have recently been proposed in a semi-partitioned environment. However, a synchronization mechanism for resource sharing among tasks in semi-partitioned scheduling has not yet been investigated. In this paper we propose and evaluate two methods for handling resource sharing under semi-partitioned scheduling in multiprocessor platforms. The main challenge addressed in this paper is to serve the resource requests of tasks that are assigned to different processors.
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| 3. |
- Afshar, Sara, et al.
(författare)
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Towards Resource Sharing under Multiprocessor Semi-Partitioned Scheduling
- 2012
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Ingår i: 7th IEEE International Symposium on Industrial Embedded Systems (SIES'12) : Conference Proceedings. - 978-1-4673-2683-4 ; s. 315-318
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Konferensbidrag (refereegranskat)abstract
- Semi-partitioned scheduling has been the subject of recent interest, compared with conventional global and partitioned scheduling algorithms for multiprocessors, due to better utilization results. In semi-partitioned scheduling most tasks are assigned to fixed processors while a low number of tasks are split up and allocated to different processors. Various techniques have recently been proposed to assign tasks in a semi-partitioned environment. However, an appropriate resource sharing mechanism for handling the resource requests between tasks in semi-partitioned scheduling has not yet been investigated. In this paper we propose two methods for handling resource sharing under semi-partitioned scheduling in multiprocessor platforms. The main challenge is to handle the resource requests of tasks that are split over multiple processors.
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| 4. |
- 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: 9th Int. Workshop on Factory Communication Systems (WFCS’12) Work-in-Progress (WiP) session. - Detmold/Lemgo, Germany.
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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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| 5. |
- 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. - 978-146731573-9 ; 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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| 6. |
- Ashjaei, Mohammad, et al.
(författare)
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The Design and Implementation of a Simulator for Switched Ethernet Networks
- 2012
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Ingår i: 3rd International Workshop on Analysis Tools andMethodologies for Embeddedand Real-time Systems. ; s. 57-62
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Konferensbidrag (refereegranskat)abstract
- In the context of Switched Ethernet, the Flexible Time-Triggered Switched Ethernet protocol (FTT-SE) was proposed to overcome the limitations and related problems of using COTS switches in real-time networks, such as overflow of switch queues due to uncontrolled arrival of packets. Although the FTT-SE protocol has been validated by several experiments on real applications, evaluation of different architectures as well as evaluation of large scale networks is not straightforward. Therefore, a simulator to evaluate different network architectures based on the FTT-SE protocol is useful. In this paper we present such a simulator. We address the extended FTT-SE protocol using multiple switches and we present a modular simulator based on Simulink/Matlab to visualize message transmissions and to evaluate end-to-end delay bounds of messages.
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| 7. |
- Ashjaei, Mohammad, et al.
(författare)
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Worst-Case Delay Analysis of Master-Slave Switched Ethernet Networks
- 2012
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Ingår i: 2nd International Workshop on Worst-Case Traversal Time (WCTT'12). - San Juan, Puerto Rico.
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Konferensbidrag (refereegranskat)abstract
- Switched Ethernet is increasingly used in real-time communication due to its intrinsic features such as micro segmentation and high throughput. However, COTS switches may impose long blocking times due to their FIFO queues and can also experience buffer overflow in outgoing queues due to uncontrolled packets arrival. Reconciling the use of ordinary switches with the needs of real-time communication requires an adequate overlay protocol. In this paper we focus on using a Master-Slave technique to overcome the COTS switch limitations in real-time applications, namely the FTT-SE protocol. We extend the protocol for large scale networks and we present the worst-case delay analysis using the Network Calculus formalism for such a network. Moreover, we assess the end-to-end delay of traffic with simulation.
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| 8. |
- Ashjaei, M., et al.
(författare)
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Worst-case delay analysis of master-slave switched ethernet networks
- 2012
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Ingår i: Proceeings of the 2nd International Workshop on Worst-Case Traversal Time : Proceeding. - 9781450316866 ; s. 15-21
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Konferensbidrag (refereegranskat)abstract
- Switched Ethernet is increasingly used in real-time communication due to its intrinsic features such as micro segmentation and high throughput. However, COTS switches may impose long blocking times due to their FIFO queues and can also experience buffer overflow in outgoing queues due to uncontrolled packets arrival. The FTT-SE protocol uses a Master-Slave technique to overcome the COTS switch limitations in real-time applications. Recently, we extended the protocol for large scale networks and in this paper we present the worst-case delay analysis using the Network Calculus formalism for such a network. Moreover, we assess the end-to-end delay of traffic with simulation concluding that the obtained analytical results present a good match with the observed delays, providing uppers bounds that vary between 0% and 50% above the maximum measured values. © 2012 ACM.
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| 9. |
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| 10. |
- Behnam, Moris, et al.
(författare)
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A Hierarchical Approach for Reconfigurable and Adaptive Embedded Systems
- 2008
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Ingår i: Proceedings of the Workshop on Adaptive and Reconfigurable Embedded Systems (APRES'08), Cyber Physical Systems Week, St. Louis, MO, USA. ; s. 51-54
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Konferensbidrag (refereegranskat)abstract
- 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.
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