| 1. |
- Behnam, Moris, et al.
(författare)
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Towards an Efficient Approach for Resource Sharing in Real-Time Multiprocessor Systems
- 2011
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Ingår i: SIES 2011 - 6th IEEE International Symposium on Industrial Embedded Systems, Conference Proceedings. - IEEE. - 9781612848204 - 978-161284820-4 ; s. 99-102
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Konferensbidrag (refereegranskat)abstract
- 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.
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| 2. |
- Nemati, Farhang, et al.
(författare)
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An Investigation of Synchronization under Multiprocessors Hierarchical Scheduling
- 2009
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Ingår i: Proceedings of the Work-In-Progress (WIP) session of the 21st Euromicro Conference on Real-Time Systems (ECRTS'09). - Dublin, Ireland.
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Konferensbidrag (refereegranskat)abstract
- community, considerable work has been done on real-timemultiprocessor scheduling algorithms where it is assumedthe tasks are independent. However in practice a typicalreal-time system includes tasks that share resources. On theother hand, synchronization in the multiprocessor contexthas not received enough attention.In this paper we propose an extension to multiprocessorhierarchical scheduling to support resource sharing. Weextend the scheduling framework with an existingsynchronization protocol for global scheduling in multi-coresystems.
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| 3. |
- Nemati, Farhang, et al.
(författare)
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Efficiently Migrating Real-Time Systems to Multi-Cores
- 2009
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Ingår i: Proceedings of 14th IEEE International Conference on Emerging Techonologies and Factory (ETFA'09). ; s. 1205-1212
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Konferensbidrag (refereegranskat)abstract
- Power consumption and thermal problems limit a further increase of speed in single-core processors. Multi-core architectures have therefore received significant interest. However, a shift to multi-core processors is a big challenge for developers of embedded real-time systems, especially considering existing “legacy” systems which have been developed with uniprocessor assumptions. These systems have been developed and maintained by many developers over many years, and cannot easily be replaced due to the huge development investments they represent. An important issue while migrating to multi-cores is how to distribute tasks among cores to increase performance offered by the multi-core platform. In this paper we propose a partitioning algorithm to efficiently distribute legacy system tasks along with newly developed ones onto different cores. The target of the partitioning is increasing system performance while ensuring correctness.
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| 4. |
- Nemati, Farhang, et al.
(författare)
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Independently-Developed Real-Time Systems on Multi-Cores with Shared Resources
- 2011
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Ingår i: 23rd EUROMICRO Conference on Real-Time Systems (ECRTS'11). - Porto, Portugal. - 978-076954442-7 ; s. 251-261
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Konferensbidrag (refereegranskat)abstract
- In this paper we propose a synchronization protocol for resource sharing among independently-developed real-time systems on multi-coreplatforms. The systems may use different scheduling policies and they may have their own local priority settings. Each system is allocated on a dedicated processor (core). In the proposed synchronization protocol, each system is abstracted by an interface which abstracts the information needed for supporting global resources. The protocol facilitates the composability of various real-time systems with different scheduling and priority settings on a multi-core platform. We have performed experimental evaluations and compared the performance of our proposed protocol (MSOS) against the two existing synchronization protocols MPCP and FMLP. The results show that the new synchronization protocol enables composability without any significant loss of performance. In fact, in most cases the new protocol performs better than at least one of the other two synchronization protocols. Hence, we believe that the proposed protocol is a viable solution for synchronization among independently-developedreal-time systems executing on a multi-core platform.
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| 5. |
- Nemati, Farhang, et al.
(författare)
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Independently-developed Systems on Multi-cores with Shared Resources
- 2010
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Ingår i: 3rd Workshop on Compositional Theory and Technology for Real-Time Embedded Systems (CRTS'10) in conjunction with the 31th IEEE International Real-Time Systems Symposium (RTSS'10). - San Diego, CA, USA.
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Konferensbidrag (refereegranskat)abstract
- In this paper we propose a synchronization protocol for resource sharing among independently-developed real-time systems on multi-core platforms. The systems may use different scheduling policies and they may have arbitrary priority settings. When using this synchronization protocol each processor is abstracted by an interface which consists of a set of requirements. A requirement depends only on the worst-case time the processor may wait for resources, i.e., the maximum number of times that the resources can be blocked by other processors. We have derived schedulability conditions for each processor and based on the analysis we extract the interface of the processor. In this paper, we focus on the cases when each system is allocated on a dedicated processor.
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| 6. |
- Nemati, Farhang, et al.
(författare)
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Investigation of Implementing a Synchronization Protocol under Multiprocessors Hierarchical Scheduling
- 2009
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Ingår i: Proceedings of the Work-In-Progress (WIP) session of 14th IEEE International Conference on Emerging Techonologies and Factory (ETFA'09). - Mallorca, Spain.
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Konferensbidrag (refereegranskat)abstract
- In the multi-core and multiprocessor domain, there has been considerable work done on scheduling techniques assuming that real-time tasks are independent. In practice a typical real-time system usually share logical resources among tasks. However, synchronization in the multiprocessor area has not received enough attention. In this paper we investigate the possibilities of extending multiprocessor hierarchical scheduling to support an existing synchronization protocol (FMLP) in multiprocessor systems. We discuss problems regarding implementation of the synchronization protocol under the multiprocessor hierarchical scheduling.
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| 7. |
- Nemati, Farhang, et al.
(författare)
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Multiprocessor Synchronization and Hierarchical Scheduling
- 2009
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Ingår i: Proceedings of the First IEEE International Workshop on Real-time Systems on Multicore Platforms: Theory and Practice (XRTS-2009) in conjunction with ICPP'09. - Vienna, Austria.
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Konferensbidrag (refereegranskat)abstract
- Multi-core architectures have received significant interestas thermal and power consumption problems limit furtherincrease of speed in single-cores. In the multi-core researchcommunity a considerable amount of work has beendone on real-time multi-core scheduling algorithms whereit is assumed tasks are independent. However, synchronizationof dependent tasks executing on multi-cores has notreceived as much attention, even though typical real-timesystems in practice include tasks that share resources.In this paper we propose a synchronization protocol forhierarchically scheduledmulti-core systems, and we presenta comparison between the presented protocol and existingmulti-core synchronization protocols. The presented protocolgroups dependent tasks that directly or indirectly sharemutually exclusive resources into independent components.Within a component dependent tasks use classical uniprocessorsynchronization protocols, such as the Stack-basedResource allocation Protocol. The components are thenscheduled on the cores by a global scheduler.There are two major approaches for scheduling multicore:partitioned and global scheduling. While most existingmulti-core synchronization protocols support only onecategory, the protocol presented in this paper is developedto handle both scheduling approaches. The presented approachis developed to allow for co-execution of existinglegacy real-time applications along with new applications,i.e., a legacy application is put into one or more componentspreserving its own (original) scheduling and synchronizationprotocols.
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| 8. |
- Åsberg, Mikael, et al.
(författare)
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Towards Hierarchical Scheduling in AUTOSAR
- 2009
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Ingår i: Proceedings of 14th IEEE International Conference on Emerging Techonologies and Factory (ETFA'09). - Mallorca, Spain.
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Konferensbidrag (refereegranskat)
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