| 1. |
- Abdullah, Syed Md Jakaria, et al.
(författare)
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Towards Implementation of Virtual-Clustered Multiprocessor Scheduling in Linux
- 2013
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Ingår i: Proceedings of the 8th IEEE International Symposium on Industrial Embedded Systems, SIES 2013. - 9781479906581 ; , s. 97-100
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Konferensbidrag (refereegranskat)abstract
- Cluster based multiprocessor scheduling can be seen as a hybrid approach combining benefits of both partitioned and global scheduling. Virtual clustering further enhances it by providing dynamic cluster resource allocation and applying hierarchical scheduling techniques. Over the years, the study of virtual cluster scheduling has been limited to theoretical analysis. In this paper, we present our initial ideas about implementing virtual cluster scheduling in Linux. The purpose of this implementation is twofold: (i) we would like to demonstrate the feasibility of its implementation in an operating system, without modifying the kernel source code, (ii) we present practical insights on the overhead of implementing this framework.
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| 2. |
- Afshar, Sara, et al.
(författare)
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Flexible spin-lock model for resource sharing in multiprocessor real-time systems
- 2014
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Ingår i: Proc. IEEE Int. Symp. Ind. Embedded Syst., SIES. - 9781479940233 ; , s. 41-51
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Konferensbidrag (refereegranskat)abstract
- Various approaches can be utilized upon resource locking for mutually exclusive resource access in multiprocessor platforms. So far two conventional approaches exist for dealing with tasks that are blocked on a global resource in a multi-processor platform. Either the blocked task performs a busy wait, i.e. spins, at the highest priority level until the resource is released, or it is suspended. Although both approaches provide mutually exclusive access to resources, they can introduce long blocking delays to tasks, which may be unacceptable for many industrial applications. In this paper, we propose a general spin-based model for resource sharing in multiprocessor platforms in which the priority of the blocked tasks during spinning can be selected arbitrarily. Moreover, we provide the analysis for two selected spin-lock priorities and we show by means of a general comparison as well as specific examples that these solutions may provide a better performance for higher priority tasks.
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| 3. |
- Afshar, Sara, et al.
(författare)
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Integrating independently developed real-time applications on a shared multi-core architecture
- 2013
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Ingår i: ACM SIGBED Review, v. 10, n. 3. - : Association for Computing Machinery (ACM). ; , s. 49-56
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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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| 4. |
- Afshar, Sara, et al.
(författare)
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Intra-component Resource Sharing on a Virtual Multiprocessor Platform
- 2016
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Ingår i: ACM SIGBED Review. - : Association for Computing Machinery (ACM). - 1551-3688. ; , s. 31-32
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Konferensbidrag (refereegranskat)abstract
- Component-based software development facilitates the development process of large and complex software systems. By the advent of multiprocessors, the independently developed components can be integrated on a multi-core platform to achieve an efficient use of system hardware and a decrease in system power consumption and costs. In this paper, we consider a virtual multiprocessor platform where each component can be dynamically allocated to any set of processors of the platform with a maximum concurrency level. Global-EDF is used for intra-component scheduling. The existing analysis for such systems have assumed that tasks are independent. In this paper, we enable intra-component resource sharing for this platform. We investigate using a spin-based resource sharing protocol with the accompanying analysis that extends the existing analysis for independent tasks. We briefly illustrate and evaluate our initial results with an example.
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| 5. |
- Afshar, Sara, et al.
(författare)
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Resource Sharing among Prioritized Real-Time Applications on Multiprocessors
- 2015
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Ingår i: ACM SIGBED Review - Special Issue on the 6th International Workshop on Compositional Theory and Technology for Real-Time Embedded Systems. - : Association for Computing Machinery (ACM). ; , s. 46-55
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Konferensbidrag (refereegranskat)abstract
- In this paper, we propose a new protocol for handling resource sharing among prioritized real-time applications composed on a multiprocessor platform. We propose an optimal priority assignment algorithm which assigns unique priorities to the applications based on information in their interfaces. We have performed experimental evaluations to compare the proposed protocol (called MSOS-Priority) to the current state of the art locking protocols under multiprocessor partitioned scheduling, i.e., MPCP, MSRP, FMLP, MSOS, and OMLP. The valuations show that MSOS-Priority mostly performs significantly better than alternative approaches.
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| 6. |
- Afshar, Sara, et al.
(författare)
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Resource sharing in a hybrid partitioned/global scheduling framework for multiprocessors
- 2015
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Ingår i: IEEE International Conference on Emerging Technologies and Factory Automation, ETFA. - 9781467379298
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Konferensbidrag (refereegranskat)abstract
- For resource-constrained embedded real-time systems, resource-efficient approaches are very important. Such an approach is presented in this paper, targeting systems where a critical application is partitioned on a multi-core platform and the remaining capacity on each core is provided to a noncritical application using resource reservation techniques. To exploit the potential parallelism of the non-critical application, global scheduling is used for its constituent tasks. Previously, we enabled intra-application resource sharing for such a framework, i.e. each application has its own dedicated set of resources. In this paper, we enable inter-application resource sharing, in particular between the critical application and the non-critical application. This effectively enables resource sharing in a hybrid partitioned/global scheduling framework on multiprocessors. For resource sharing, we use a spin-based synchronization protocol. We derive blocking bounds and extend existing schedulability analysis for such a system.
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| 7. |
- Afshar, Sara, et al.
(författare)
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Resource Sharing Under Global Scheduling with Partial Processor Bandwidth
- 2015
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Ingår i: 2015 10th IEEE International Symposium on Industrial Embedded Systems, SIES 2015 - Proceedings. - 9781467377119 ; , s. 195-206
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Konferensbidrag (refereegranskat)abstract
- Resource efficient approaches are of great importance for resource constrained embedded systems. In this paper, we present an approach targeting systems where tasks of a critical application are partitioned on a multi-core platform and by using resource reservation techniques, the remaining bandwidth capacity on each core is utilized for one or a set of non-critical application(s). To provide a resource efficient solution and to exploit the potential parallelism of the extra applications on the multi-core processor, global scheduling is used to schedule the tasks of the non-critical applications. Recently a specific instantiation of such a system has been studied where tasks do not share resources other than the processor. In this paper, we enable semaphore-based resource sharing among tasks within critical and non-critical applications using a suspension-based synchronization protocol. Tasks of non-critical applications have partial access to the processor bandwidth. The paper provides the systems schedulability analysis where blocking due to resource sharing is bounded. Further, we perform experimental evaluations under balanced and unbalanced allocation of tasks of a critical application to cores.
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| 8. |
- 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). - : IEEE. - 9781467330176 - 9780769548241 ; , 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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| 9. |
- 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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| 10. |
- 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). - : IEEE. - 9781467326834 - 9781467326858 ; , 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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