| 11. |
- Balasubramanian, S.M.N, et al.
(författare)
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A dual shared stack for FSLM in Erika enterprise
- 2017
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Ingår i: The 23rd IEEE International Conference on Embedded and Real-Time Computing Systems and Applications - WiP Session RTCSA'17.
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Konferensbidrag (refereegranskat)abstract
- Recently, the flexible spin-lock model (FSLM) has been introduced, unifying spin-based and suspension-based resource sharing protocols for real-time multi-core platforms. Unlike the multiprocessor stack resource policy (MSRP), FSLM doesn’t allow tasks on a core to share a single stack, however. In this paper, we present a hypothesis claiming that for a restricted range of spin-lock priorities, FSLM requires only two stacks. We briefly describe our implementation of a dual stack for FSLM in the Erika Enterprise RTOS as instantiated on an Altera Nios II platform using 4 soft-core processors.
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| 12. |
- Balasubramanian, S.M.N, et al.
(författare)
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Incorporating implementation overheads in the analysis for the flexible spin-lock model
- 2017
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Ingår i: IECON 2017 - 43RD ANNUAL CONFERENCE OF THE IEEE INDUSTRIAL ELECTRONICS SOCIETY. - 9781538611272 ; , s. 411-8418
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Konferensbidrag (refereegranskat)abstract
- The flexible spin-lock model (FSLM) unifies suspension-based and spin-based resource sharing protocols for partitioned fixed-priority preemptive scheduling based real-time multiprocessor platforms. Recent work has been done in defining the protocol for FSLM and providing a schedulability analysis without accounting for the implementation overheads. In this paper, we extend the analysis for FSLM with implementation overheads. Utilizing an initial implementation of FSLM in the OSEK/VDX-compliant Erika Enterprise RTOS on an Altera Nios II platform using 4 soft-core processors, we present an improved implementation. Given the design of the implementation, the overheads are characterized and incorporated in specific terms of the existing analysis. The paper also supplements the analysis with measurement results, enabling an analytical comparison of FSLM with the natively provided multiprocessor stack resource policy (MSRP), which may serve as a guideline for the choice of FSLM or MSRP for a specific application.
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| 13. |
- Balasubramanian, S. M. N., et al.
(författare)
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Practical challenges for FSLM
- 2018
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Ingår i: Proceedings - 2018 IEEE 24th International Conference on Embedded and Real-Time Computing Systems and Applications, RTCSA 2018. - : Institute of Electrical and Electronics Engineers Inc.. - 9781538677599 ; , s. 238-239
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Konferensbidrag (refereegranskat)abstract
- The flexible spin-lock model (FSLM) unifies suspension-based and spin-based resource access protocols for partitioned fixed-priority preemptive scheduling based real-time multi-core platforms. Recent work has been done in defining the protocol for FSLM, providing schedulability analysis, and investigating the practical consequences of the theoretical model. FSLM complies to the AUTOSAR standard for the automotive industry, and prototype implementations of FSLM in the OSEK/VDX-complaint Erika Enterprise Real-Time Operating System have been realized. In this paper, we briefly describe some practical challenges to improve efficiency and generality.
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| 14. |
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| 15. |
- Behnam, Moris, et al.
(författare)
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Improved SIRAP analysis for synchronization in hierarchical scheduled real-time systems
- 2009
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Ingår i: Proceedings of 14th IEEE International Conference on Emerging Techonologies and Factory (ETFA'09). - 9781424427284
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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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| 16. |
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| 17. |
- Bril, Reinder J., et al.
(författare)
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Integrating Cache-Related Pre-emption Delays into Analysis of Fixed Priority Scheduling with Pre-emption Thresholds
- 2015
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Ingår i: Proceedings - Real-Time Systems Symposium. - 9781479972890 ; , s. 161-172
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Konferensbidrag (refereegranskat)abstract
- Cache-related pre-emption delays (CRPD) have been integrated into the schedulability analysis of sporadic tasks with constrained deadlines for fixed-priority pre-emptive scheduling (FPPS). This paper generalizes that work by integrating CRPD into the schedulability analysis of tasks with arbitrary deadlines for fixed-priority pre-emption threshold scheduling (FPTS). The analysis is complemented by an optimal threshold assignment algorithm that minimizes CRPD. The paper includes a comparative evaluation of the schedulability ratios of FPPS and FPTS, for constrained-deadline tasks, taking CRPD into account.
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| 18. |
- J. Bril, Reinder, et al.
(författare)
-
Fixed priority scheduling with pre-emption thresholds and cache-related pre-emption delays : integrated analysis and evaluation
- 2017
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Ingår i: Real-time systems. - : Springer Science and Business Media LLC. - 0922-6443 .- 1573-1383. ; 53:4, s. 403-466
-
Tidskriftsartikel (refereegranskat)abstract
- Commercial off-the-shelf programmable platforms for real-time systems typically contain a cache to bridge the gap between the processor speed and main memory speed. Because cache-related pre-emption delays (CRPD) can have a significant influence on the computation times of tasks, CRPD have been integrated in the response time analysis for fixed-priority pre-emptive scheduling (FPPS). This paper presents CRPD aware response-time analysis of sporadic tasks with arbitrary deadlines for fixed-priority pre-emption threshold scheduling (FPTS), generalizing earlier work. The analysis is complemented by an optimal (pre-emption) threshold assignment algorithm, assuming the priorities of tasks are given. We further improve upon these results by presenting an algorithm that searches for a layout of tasks in memory that makes a task set schedulable. The paper includes an extensive comparative evaluation of the schedulability ratios of FPPS and FPTS, taking CRPD into account. The practical relevance of our work stems from FPTS support in AUTOSAR, a standardized development model for the automotive industry. [(This paper forms an extended version of Bril et al. (in Proceedings of 35th IEEE real-time systems symposium (RTSS), 2014). The main extensions are described in Sect. 1.2.].
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| 19. |
- Keskin, Ugur, et al.
(författare)
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Improving the global schedulability analysis of overrun without payback
- 2010
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Ingår i: Proceedings of the Work-In-Progress (WIP) session of the 22nd Euromicro Conference on Real-Time Systems (ECRTS'10).
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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.
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| 20. |
- Nemati, Farhang, Senior Lecturer, 1975-, et al.
(författare)
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Investigation of Implementing a Synchronization Protocol under Multiprocessors Hierarchical Scheduling
- 2009
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Ingår i: 2009 IEEE Conference on Emerging Technologies & Factory Automation. - : IEEE. - 9781424427277 - 9781424427284
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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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