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Träfflista för sökning "WFRF:(Behnam Moris) ;pers:(J. Bril Reinder)"

Sökning: WFRF:(Behnam Moris) > J. Bril Reinder

  • Resultat 1-10 av 14
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1.
  • Afshar, Sara, et al. (författare)
  • Flexible Spin-Lock Model for Resource Sharing in Multiprocessor Real-Time Systems
  • 2014
  • Ingår i: 9th IEEE International SIES SIES'14. - Pisa, Italy.
  • 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 multiprocessor 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 spinbased 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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2.
  • Afshar, Sara, et al. (författare)
  • Per Processor Spin-Lock Priority for Partitioned Multiprocessor Real-Time Systems
  • 2014
  • Rapport (övrigt vetenskapligt)abstract
    • Two traditional approaches exist for a task that is blocked on a global resource; a task either performs a non-preemptive busy wait, i.e., spins, or suspends and releases the processor. Previously, we have shown that both approaches can be viewed as spinning either at the highest priority HP or at the lowest priority on the processor LP, respectively. Based on this view, previously we have generalized a task's blocking behavioral model, as spinning at any arbitrary priority level. In this paper, we focus on a particular class of spin-lock protocols from the introduced flexible spin-lock model where spinning is performed at a priority equal to or higher than the highest local ceiling of the global resources accessed on a processor referred to as CP spin-lock approach. In this paper, we assume that all tasks of a specific processor are spinning on the same priority level. Given this class and assumption, we show that there exists a spin-lock protocol in this range that dominates the classic spin-lock protocol which tasks spin on highest priority level (HP). However we show that this new approach is incomparable with the CP spin-lock approach. Moreover, we show that there may exist an intermediate spin-lock approach between the priority used by CP spin-lock approach and the new introduced spin-lock approach that can make a task set schedulable when those two cannot. We provide an extensive evaluation results comparing the HP, CP and the new proposed approach.
3.
  • Ashjaei, Mohammad, et al. (författare)
  • Reduced Buffering Solution for Multi-Hop HaRTES Switched Ethernet Networks
  • 2014
  • Ingår i: The 20th IEEE International Conference on embedded and Real-Time Computing Systems and Applications RTCSA'14. - 978-1479939534 ; s. Article number 6910504
  • Konferensbidrag (refereegranskat)abstract
    • In the context of switched Ethernet networks, multi-hop communication is essential as the networks in industrial applications comprise a high amount of nodes, that is far beyond the capability of a single switch. In this paper, we focus on multi-hop communication using HaRTES switches. The HaRTES switch is a modified Ethernet switch that provides real-time traffic scheduling, dynamic Quality-of-Service and temporal isolation between real-time and non-real-time traffic. Herein, we propose a method, called Reduced Buffering Scheme, to conduct the traffic through multiple HaRTES switches in a multi-hop HaRTES architecture. In order to enable the new scheduling method we propose to modify the HaRTES switch structure. Moreover, we develop a response time analysis for the new method. We also compare the proposed method with a method previously proposed, called Distributed Global Scheduling, based on their traffic response times. We show that, the new method forwards all types of traffic including the highest, the medium and the lowest priority, faster than the previous method in most of the cases. Furthermore, we show that the new method performs even better for larger networks compared with the previous one.
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5.
  • Behnam, Moris, et al. (författare)
  • Improved SIRAP analysis for synchronization in hierarchical scheduled real-time systems
  • 2009
  • Ingår i: Proceedings of 14th IEEE International Conference on Emerging Techonologies and Factory (ETFA'09). - 9781424427284
  • Konferensbidrag (refereegranskat)abstract
    • We present our ongoing work on synchronization in hierarchical scheduled real-time systems, where tasks are scheduled using fixed-priority pre-emptive scheduling. In this paper, we show that the original local schedulability analysis of the synchronization protocol SIRAP is very pessimistic when tasks of a subsystem access many global shared resources. The analysis therefore suggests that a subsystem requires more CPU resources than necessary. A new way to perform the schedulability analysis is presented which can make the SIRAP protocol more efficient in terms of calculated CPU resource needs.
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7.
  • Keskin, Ugur, et al. (författare)
  • Improving the global schedulability analysis of overrun without payback
  • 2010
  • Ingår i: Proceedings of the Work-In-Progress (WIP) session of the 22nd Euromicro Conference on Real-Time Systems (ECRTS'10).
  • Konferensbidrag (refereegranskat)abstract
    • Overrun without payback has been proposed asa mechanism for a stack resource policy (SRP) based synchronizationprotocol for hierarchical scheduling frameworks(HSFs). In this paper we reconsider the global schedulabilityanalysis of an HSF based on two-level fixed-priority preemptivescheduling (FPPS) using overrun without payback asa mechanism. Improved analysis is presented based on theobservation that there is no need to guarantee the overrunbudget before the end of the budget period, because thatadditional amount of resources is only meant to prevent depletionof a budget during global resource access. The resultingimprovement is illustrated by means of an example. Thepossibility to discard the remainder of an overrun budget upona replenishment is briefly considered as a further improvementand its potential is shown using the same example.
8.
  • Nemati, Farhang, et al. (författare)
  • Investigation of Implementing a Synchronization Protocol under Multiprocessors Hierarchical Scheduling
  • 2009
  • Ingår i: Proceedings of the Work-In-Progress (WIP) session of 14th IEEE International Conference on Emerging Techonologies and Factory (ETFA'09). - 9781424427284
  • 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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10.
  • Sandström, Kristian, et al. (författare)
  • On Jitter in Time Partitioned Real-Time Systems
  • 2012
  • Ingår i: IEEE Symposium on Emerging Technologies and Factory Automation, ETFA 2012. - 978-146734737-2
  • Konferensbidrag (refereegranskat)abstract
    • Recent trends towards adopting hypervisors, hierarchical scheduling, and other virtualization technologies that achieve partitioned access to the CPU and other resources impose significant impact with respect to jitter performance in embedded real-time systems. In this paper we make a first step towards characterization, modeling and calculation of this jitter.
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