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Nemati, F., Behnam, M. & Nolte, T. (2011). Independently-Developed Real-Time Systems on Multi-Cores with Shared Resources. In: 2011 23rd Euromicro Conference on Real-Time Systems: Proceedings. Paper presented at 23rd Euromicro Conference on Real-Time Systems (ECRTS 2011), Porto, Portugal, July 5-8, 2011 (pp. 251-261). IEEE
Open this publication in new window or tab >>Independently-Developed Real-Time Systems on Multi-Cores with Shared Resources
2011 (English)In: 2011 23rd Euromicro Conference on Real-Time Systems: Proceedings, IEEE, 2011, p. 251-261Conference paper, Published paper (Refereed)
Abstract [en]

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.

Place, publisher, year, edition, pages
IEEE, 2011
Series
Euromicro Conference on Real-Time Systems (ECRTS), ISSN 1068-3070, E-ISSN 2377-5998
National Category
Computer and Information Sciences
Identifiers
urn:nbn:se:oru:diva-77151 (URN)10.1109/ECRTS.2011.31 (DOI)000323257300023 ()2-s2.0-80053001354 (Scopus ID)978-1-4577-0643-1 (ISBN)
Conference
23rd Euromicro Conference on Real-Time Systems (ECRTS 2011), Porto, Portugal, July 5-8, 2011
Available from: 2019-10-10 Created: 2019-10-10 Last updated: 2019-10-17Bibliographically approved
Nemati, F., Behnam, M. & Nolte, T. (2011). Sharing Resources among Independently-developed Systems on Multi-cores. ACM SIGBED Review, 8(1), 46-53
Open this publication in new window or tab >>Sharing Resources among Independently-developed Systems on Multi-cores
2011 (English)In: ACM SIGBED Review, ISSN 1551-3688, Vol. 8, no 1, p. 46-53Article in journal (Refereed) Published
Abstract [en]

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.

Place, publisher, year, edition, pages
New York: ACM SIGBED, 2011
National Category
Computer and Information Sciences
Identifiers
urn:nbn:se:oru:diva-77154 (URN)10.1145/1967021.1967027 (DOI)
Available from: 2019-10-10 Created: 2019-10-10 Last updated: 2019-10-17Bibliographically approved
Behnam, M., Nemati, F., Nolte, T. & Grahn, H. (2011). Towards an Efficient Approach for Resource Sharing in Real-Time Multiprocessor Systems. In: 2011 6th IEEE International Symposium on Industrial and Embedded Systems: Conference Proceedings. Paper presented at 6th IEEE International Symposium on Industrial Embedded Systems (SIES 2011), Västerås, Sweden, June 15-17, 2011 (pp. 99-102). IEEE
Open this publication in new window or tab >>Towards an Efficient Approach for Resource Sharing in Real-Time Multiprocessor Systems
2011 (English)In: 2011 6th IEEE International Symposium on Industrial and Embedded Systems: Conference Proceedings, IEEE , 2011, p. 99-102Conference paper, Published 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.

Place, publisher, year, edition, pages
IEEE, 2011
Series
Symposium on Industrial Embedded Systems proceedings, ISSN 2150-3109, E-ISSN 2150-3117
National Category
Computer Sciences
Identifiers
urn:nbn:se:oru:diva-77145 (URN)10.1109/SIES.2011.5953690 (DOI)2-s2.0-80051957053 (Scopus ID)978-1-61284-818-1 (ISBN)978-1-61284-819-8 (ISBN)
Conference
6th IEEE International Symposium on Industrial Embedded Systems (SIES 2011), Västerås, Sweden, June 15-17, 2011
Funder
Knowledge Foundation
Available from: 2019-10-10 Created: 2019-10-10 Last updated: 2019-10-18Bibliographically approved
Nemati, F., Nolte, T. & Behnam, M. (2010). Partitioning Real-Time Systems on Multiprocessors with Shared Resources. In: Lu, CY; Masuzawa, T; Mosbah, M (Ed.), Principles of Distributed Systems: . Paper presented at 14th International Conference on Principles of Distributed Systems (OPODIS 2010), Tozeur, Tunisia, December 14-17, 2010 (pp. 253-269). Springer, 6490
Open this publication in new window or tab >>Partitioning Real-Time Systems on Multiprocessors with Shared Resources
2010 (English)In: Principles of Distributed Systems / [ed] Lu, CY; Masuzawa, T; Mosbah, M, Springer , 2010, Vol. 6490, p. 253-269Conference paper, Published paper (Refereed)
Abstract [en]

There are two main approaches to task scheduling on multiprocessor/multi-core platforms; 1) global scheduling, under which migration of tasks among processors is allowed, and 2) partitioned scheduling under which tasks are allocated onto processors and task migration is not allowed. Under global scheduling a higher utilization bound can be achieved, but in practice the overheads of migrating tasks is high. On the other hand under partitioned scheduling, besides simplicity and efficiency, existing scheduling and synchronization methods developed for uniprocessor platforms can more easily be extended to partitioned scheduling. However the partitioned scheduling protocols suffer from the problem of partitioning tasks among processors/cores which is a bin-packing problem. Therefore, several heuristic algorithms have been developed for partitioning a task set on multiprocessor platforms. However, these algorithms typically assume independent tasks while in practice real-time systems often contain tasks that share resources and hence may block each other.

In this paper we propose a blocking-aware partitioning algorithm which allocates a task~set onto processors in a way that the overall amount of blocking times of tasks are decreased. The algorithm reduces the total utilization which, in turn, has the potential to decrease the total number of required processors (cores). In this paper we evaluate our algorithm and compare it with an existing similar algorithm. The comparison criteria includes both number of schedulable systems as well as processor reduction performance.

Place, publisher, year, edition, pages
Springer, 2010
Series
Lecture Notes in Computer Science, ISSN 0302-9743 ; 6490
National Category
Computer Sciences
Identifiers
urn:nbn:se:oru:diva-77166 (URN)10.1007/978-3-642-17653-1_20 (DOI)000290495600020 ()2-s2.0-78650872347 (Scopus ID)978-3-642-17652-4 (ISBN)978-3-642-17653-1 (ISBN)
Conference
14th International Conference on Principles of Distributed Systems (OPODIS 2010), Tozeur, Tunisia, December 14-17, 2010
Funder
Swedish Foundation for Strategic Research
Available from: 2019-10-10 Created: 2019-10-10 Last updated: 2019-10-17Bibliographically approved
Nemati, F., Behnam, M. & Nolte, T. (2009). An Investigation of Synchronization under Multiprocessors Hierarchical Scheduling. In: Proceedings of the Work-In-Progress (WIP) session of the 21st Euromicro Conference on Real-Time Systems (ECRTS'09): . Paper presented at Work-In-Progress (WIP) session of the 21st Euromicro Conference on Real-Time Systems (ECRTS'09), Dublin, Ireland, July 1-3, 2009.
Open this publication in new window or tab >>An Investigation of Synchronization under Multiprocessors Hierarchical Scheduling
2009 (English)In: Proceedings of the Work-In-Progress (WIP) session of the 21st Euromicro Conference on Real-Time Systems (ECRTS'09), 2009Conference paper, Published paper (Refereed)
Abstract [en]

In the multi-core and multiprocessor research community, considerable work has been done on real-time multiprocessor scheduling algorithms where it is assumed the tasks are independent. However in practice a typical real-time system includes tasks that share resources. On the other hand, synchronization in the multiprocessor context has not received enough attention.

In this paper we propose an extension to multiprocessor hierarchical scheduling to support resource sharing. We extend the scheduling framework with an existing synchronization protocol for global scheduling in multi-core systems.

National Category
Computer Systems
Identifiers
urn:nbn:se:oru:diva-77149 (URN)
Conference
Work-In-Progress (WIP) session of the 21st Euromicro Conference on Real-Time Systems (ECRTS'09), Dublin, Ireland, July 1-3, 2009
Funder
Swedish Foundation for Strategic Research
Available from: 2019-10-10 Created: 2019-10-10 Last updated: 2019-10-17Bibliographically approved
Nemati, F., Behnam, M. & Nolte, T. (2009). Efficiently Migrating Real-Time Systems to Multi-Cores. In: 2009 IEEE Conference on Emerging Technologies & Factory Automation: . Paper presented at 2009 IEEE Conference on Emerging Technologies and Factory Automation (ETFA 2009), Mallorca, Spain, September 22-26, 2009 (pp. 1205-1212). IEEE
Open this publication in new window or tab >>Efficiently Migrating Real-Time Systems to Multi-Cores
2009 (English)In: 2009 IEEE Conference on Emerging Technologies & Factory Automation, IEEE, 2009, p. 1205-1212Conference paper, Published paper (Refereed)
Abstract [en]

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.

Place, publisher, year, edition, pages
IEEE, 2009
Series
IEEE International Conference on Emerging Technologies and Factory Automation-ETFA, ISSN 1946-0740, E-ISSN 1946-0759
National Category
Computer Sciences
Identifiers
urn:nbn:se:oru:diva-77150 (URN)10.1109/ETFA.2009.5347136 (DOI)000355314000149 ()2-s2.0-77949885068 (Scopus ID)978-1-4244-2728-4 (ISBN)978-1-4244-2727-7 (ISBN)
Conference
2009 IEEE Conference on Emerging Technologies and Factory Automation (ETFA 2009), Mallorca, Spain, September 22-26, 2009
Available from: 2019-10-10 Created: 2019-10-10 Last updated: 2019-10-17Bibliographically approved
Nemati, F., Behnam, M., Nolte, T. & J. Bril, R. (2009). Investigation of Implementing a Synchronization Protocol under Multiprocessors Hierarchical Scheduling. In: 2009 IEEE Conference on Emerging Technologies & Factory Automation: . Paper presented at 2009 IEEE Conference on Emerging Technologies and Factory Automation (ETFA 2009), Mallorca, Spain, September 22-26, 2009. IEEE
Open this publication in new window or tab >>Investigation of Implementing a Synchronization Protocol under Multiprocessors Hierarchical Scheduling
2009 (English)In: 2009 IEEE Conference on Emerging Technologies & Factory Automation, IEEE, 2009Conference paper, Published paper (Refereed)
Abstract [en]

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.

Place, publisher, year, edition, pages
IEEE, 2009
Series
International Conference on Emerging Technologies and Factory Automation (ETFA), ISSN 1946-0740, E-ISSN 1946-0759
National Category
Computer Sciences
Identifiers
urn:nbn:se:oru:diva-77155 (URN)10.1109/ETFA.2009.5347221 (DOI)000355314000226 ()2-s2.0-77949901371 (Scopus ID)978-1-4244-2727-7 (ISBN)978-1-4244-2728-4 (ISBN)
Conference
2009 IEEE Conference on Emerging Technologies and Factory Automation (ETFA 2009), Mallorca, Spain, September 22-26, 2009
Available from: 2019-10-10 Created: 2019-10-10 Last updated: 2019-10-17Bibliographically approved
Nemati, F., Behnam, M. & Nolte, T. (2009). Multiprocessor Synchronization and Hierarchical Scheduling. In: Barolli, L; Feng, WC (Ed.), 2009 International Conference on Parallel Processing Workshops: Proceedings. Paper presented at 38th International Conference on Parallel Processing Location, Vienna, Austria, September 22-25, 2009 (pp. 58-64). IEEE
Open this publication in new window or tab >>Multiprocessor Synchronization and Hierarchical Scheduling
2009 (English)In: 2009 International Conference on Parallel Processing Workshops: Proceedings / [ed] Barolli, L; Feng, WC, IEEE, 2009, p. 58-64Conference paper, Published paper (Refereed)
Abstract [en]

Multi-core architectures have received significant interest as thermal and power consumption problems limit further increase of speed in single-cores. In the multi-core research community a considerable amount of work has been done on real-time multi-core scheduling algorithms where it is assumed tasks are independent. However, synchronization of dependent tasks executing on multi-cores has not received as much attention, even though typical real-time systems in practice include tasks that share resources.

In this paper we propose a synchronization protocol for hierarchically scheduledmulti-core systems, and we present a comparison between the presented protocol and existing multi-core synchronization protocols. The presented protocol groups dependent tasks that directly or indirectly share mutually exclusive resources into independent components. Within a component dependent tasks use classical uniprocessor synchronization protocols, such as the Stack-based Resource allocation Protocol. The components are then scheduled on the cores by a global scheduler.

There are two major approaches for scheduling multicore: partitioned and global scheduling. While most existing multi-core synchronization protocols support only one category, the protocol presented in this paper is developed to handle both scheduling approaches. The presented approach is developed to allow for co-execution of existing legacy real-time applications along with new applications, i.e., a legacy application is put into one or more components preserving its own (original) scheduling and synchronization protocols.

Place, publisher, year, edition, pages
IEEE, 2009
Series
Proceedings of the International Conference on Parallel Processing, ISSN 0190-3918, E-ISSN 2332-5690
National Category
Computer Sciences
Identifiers
urn:nbn:se:oru:diva-77153 (URN)10.1109/ICPPW.2009.44 (DOI)000289915300010 ()2-s2.0-77949505745 (Scopus ID)978-1-4244-4923-1 (ISBN)978-0-7695-3803-7 (ISBN)
Conference
38th International Conference on Parallel Processing Location, Vienna, Austria, September 22-25, 2009
Funder
Swedish Foundation for Strategic Research
Available from: 2019-10-10 Created: 2019-10-10 Last updated: 2019-10-17Bibliographically approved
Åsberg, M., Behnam, M., Nemati, F. & Nolte, T. (2009). Towards Hierarchical Scheduling in AUTOSAR. In: 2009 IEEE Conference on Emerging Technologies & Factory Automation: . Paper presented at 14th IEEE International Conference on Emerging Technologies and Factory Automation (ETFA 2009), Mallorca, Spain, September 2-26, 2009. IEEE, Article ID 5347133.
Open this publication in new window or tab >>Towards Hierarchical Scheduling in AUTOSAR
2009 (English)In: 2009 IEEE Conference on Emerging Technologies & Factory Automation, IEEE, 2009, article id 5347133Conference paper, Published paper (Refereed)
Abstract [en]

AUTOSAR [17] is a partnership between automotive manufactures and suppliers. It aims at standardizing the automotive software architecture and separating software and hardware. This approach makes software more independent, maintainable, reuseable, etc. Still there is much work to do in order for this standard to be usable. This paper focus on automotive software integration in AUTOSAR, with the use of hierarchical scheduling as an enabling technology. At this point, AUTOSARcomponents do not have any timing relation with its tasks [19, 20]. This causes an unpredictive runtime behavior which can only be analyzed and verified after integration phase. We will discuss how integration can be done in AUTOSAR, with runtime temporal isolation of components. This will enable schedulability analysis at the level of components rather than at the level of tasks.

Place, publisher, year, edition, pages
IEEE, 2009
Series
IEEE International Conference on Emerging Technologies and Factory Automation-ETFA, ISSN 1946-0740, E-ISSN 1946-0759
National Category
Engineering and Technology
Identifiers
urn:nbn:se:oru:diva-77168 (URN)10.1109/ETFA.2009.5347133 (DOI)000355314000146 ()2-s2.0-77949897314 (Scopus ID)978-1-4244-2728-4 (ISBN)978-1-4244-2727-7 (ISBN)
Conference
14th IEEE International Conference on Emerging Technologies and Factory Automation (ETFA 2009), Mallorca, Spain, September 2-26, 2009
Available from: 2019-10-10 Created: 2019-10-10 Last updated: 2019-10-15Bibliographically approved
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Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-1687-930X

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