| 21. |
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| 22. |
- Sandström, Kristian, et al.
(författare)
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On Jitter in Time Partitioned Real-Time Systems
- 2012
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Ingår i: Emerging Technologies & Factory Automation (ETFA), 2012 IEEE 17th Conference on. - 9781467347358 ; , s. 1-4
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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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| 23. |
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| 24. |
- Van Den Heuvel, M. M. H. P., et al.
(författare)
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Optimal and fast composition of resource-sharing components in hierarchical real-time systems
- 2014
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Ingår i: RTCSA 2014 - 20th IEEE International Conference on Embedded and Real-Time Computing Systems and Applications. - 9781479939534 ; , s. Article number 6910547-
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Konferensbidrag (refereegranskat)abstract
- In this paper we consider various flavors of the stack resource policy (SRP) for arbitrating access to shared resources in a hierarchical scheduling framework (HSF) upon a uni-processor. We propose algorithms for exploring and selecting the (local) resource ceilings within components, such that it results in an optimal composition of resource-sharing components in an HSF. Existing methods are non-optimal, because (i) they optimize just the length of global non-preemptive execution of tasks and (ii) they do not detect whether or not resources are shared globally (i.e., between tasks of different components). Lifting these limitations leads to an exponential growth of the design space. This paper contributes a fast three-step methodology which lifts these limitations, i.e., we apply the SRP at each level of the HSF to just the resources being shared. Our algorithm selects those component interfaces (i.e., by fixing the local resource ceilings of each component) that minimize the system load.
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| 25. |
- van den Heuvel, Martijn, et al.
(författare)
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Opaque Analysis for Resource Sharing in Compositional Real-Time Systems
- 2011
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Ingår i: 4th Workshop on Compositional Theory and Technology for Real-Time Embedded Systems (CRTS'11).
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Konferensbidrag (refereegranskat)abstract
- In this paper we propose opaque analysis methods to integrate dependent real-time components into hierarchical fixed-priority scheduled systems. To arbitrate mutually exclusive resource access between components, we consider two existing protocols: HSRP - comprising overrun with and without payback - and SIRAP. An opaque analysis allows to postpone the choice of a synchronization protocol until component integration time. First, we identify the sources of pessimism in the existing analysis techniques and we conclude that both protocols assume different models in their local analysis. In particular, the compo- sitional analysis for overrun with payback (OWP) is not opaque and is pessimistic. The latter makes OWP expensive compared to its counter part without a payback mechanism (ONP). This paper presents an opaque and less pessimistic OWP analysis. Secondly, SIRAP requires more timing information to perform a task-level schedulability analysis. In many practical situations, however, detailed timing characteristics of tasks are hard to obtain. We introduce an opaque analysis for SIRAP using the analysis of ONP to reduce the required timing information during the local analysis. We show that the analysis for ONP cannot deem systems schedulable which are infeasible with SIRAP. The SIRAP analysis may therefore reduce the required system resources of a component by sacrificing the choice for an arbitrary synchronization protocol at system integration time.
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| 26. |
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| 27. |
- Åsberg, Mikael, et al.
(författare)
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Implementation of Overrun and Skipping in VxWorks
- 2010
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Ingår i: Proceedings of the 6th International Workshop on Operating Systems Platforms for Embedded Real-Time Applications. - Brussels, Belgium.
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Konferensbidrag (refereegranskat)
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