HARTIK 3.0: a portable system for developing real-time applications

Lamastra, G.; Lipari, Giuseppe; Buttazzo, Giuseppe; Casile, Antonino; Conticelli, F.

doi:10.1109/rtcsa.1997.629172

Cited by 20 publications

(8 citation statements)

References 14 publications

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“…The elastic task model has been implemented on top of the HARTIK kernel [5], [11] to perform some experiments on multimedia applications and verify the results predicted by the theory. In particular, the elastic guarantee mechanism has been implemented as a high priority task, the QoS manager, activated by the other tasks when they are created or when they want to change their period.…”

Section: Resultsmentioning

confidence: 94%

“…Furthermore, the elastic mechanism can easily be implemented on top of classical real-time kernels and can be used under fixed or dynamic priority scheduling algorithms. The experimental results shown in this paper have been conducted by implementing the elastic mechanism on the HARTIK kernel [5], [11].…”

Section: Table 5 Task Set Parameters Used For the Second Experimentsmentioning

confidence: 99%

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Elastic scheduling for flexible workload management

Buttazzo

Lipari

Caccamo

et al. 2002

IEEE Trans. Comput.

Self Cite

218

179

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AbstractÐAn increasing number of real-time applications, related to multimedia and adaptive control systems, require greater flexibility than classical real-time theory usually permits. In this paper, we present a novel scheduling framework in which tasks are treated as springs with given elastic coefficients to better conform to the actual load conditions. Under this model, periodic tasks can intentionally change their execution rate to provide different quality of service and the other tasks can automatically adapt their periods to keep the system underloaded. The proposed model can also be used to handle overload conditions in a more flexible way and to provide a simple and efficient mechanism for controlling a system's performance as a function of the current load.

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Section: Resultsmentioning

confidence: 94%

Section: Table 5 Task Set Parameters Used For the Second Experimentsmentioning

confidence: 99%

Elastic scheduling for flexible workload management

Buttazzo

Lipari

Caccamo

et al. 2002

IEEE Trans. Comput.

Self Cite

218

179

View full text Add to dashboard Cite

show abstract

“…The proposed CBS algorithm has been implemented on the HARTIK kernel (Buttazzo, 1993;Lamastra et al, 1997), to support some sample multimedia applications. The algorithm can also be easily implemented in different real-time kernels where time accounting is provided.…”

Section: Implementation and Experimental Resultsmentioning

confidence: 99%

Resource Reservation in Dynamic Real-Time Systems

2004

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Abstract. This paper focuses on the problem of providing ef®cient run-time support to multimedia applications in a real-time system, where different types of tasks (characterized by different criticality) can coexist. Whereas critical real-time tasks (hard tasks) are guaranteed based on worst-case execution times and minimum interarrival times, multimedia tasks are served based on mean parameters. A novel bandwidth reservation mechanism (the constant bandwidth server) allows real-time tasks to execute in a dynamic environment under a temporal protection mechanism, so that each task will never exceed a prede®ned bandwidth, independently of its actual requests. The paper also discusses how the proposed server can be used for handling aperiodic tasks ef®ciently and how a statistical analysis can be applied to perform a probabilistic guarantee of soft tasks. The performance of the proposed method is compared with that of similar service mechanisms (dynamic real-time servers and proportional share schedulers) through extensive simulation experiments.

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“…Both benefits are mainly due to the CSP's early blocking, a feature shown to be especially appropriate in a system where hard and soft tasks must share memory. As a curiosity, it is interesting to note that Lamastra et al [Lam97] reached a similar conclusion in their operating system, HARTIK, which also mixes hard and soft tasks but uses a different scheduling paradigm (Earliest Deadline First) and a different synchronization protocol (Stack Resource Protocol). …”

Section: High-level Evaluationmentioning

confidence: 83%

“…However, typical research studies in FRTS do not address the issue of communication among tasks of different criticality, but define soft tasks (or even all types of tasks) to be independent. Exception of this are the Open System architecture [Den97], which proposes the Non-Preemptable Critical Section (NPS) protocol as a mechanism for safely sharing global data, and the HARTIK operating system [Lam97], in which the Stack Resource Protocol [Bak91] has been adapted in order to allow both hard and soft tasks to share memory.…”

Section: Introductionmentioning

confidence: 99%

Flexible Real-Time Linux a New Environment for Flexible Hard Real-Time Systems

Barrena¹,

Martín²

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A Ana, por su eterna (im)paciencia, y en memoria de nuestro amigo LucasI have never begun a novel with more misgiving. If I call it a novel it is only because I don't know what else to call it. I have little story to tell and I end neither with a death nor a marriage. W. SOMERSET MAUGHAM:The razor's edge /* * Buddy system. Hairy. You really aren't * expected to understand this * * Hint: -mask = 1+˜mask */ LINUS TORVALDS:/usr/src/linux/mm/page alloc.c AbstractThis thesis proposes a new general framework for building flexible hard real-time systems, that is, systems featuring both hard timing constraints and flexible behaviour. The proposed framework is capable of integrating tasks with different criticality levels as well as combining different scheduling paradigms into the same system. As a result, the framework completely guarantees the timing requirements of hard tasks, while also allowing for an adaptive and intelligent scheduling of non-hard tasks. The framework is divided into a computational model, a software architecture and a set of services. The computational model proposes building a flexible real-time application as a set of tasks, with each task being structured as a sequence of mandatory and optional components. The software architecture proposes separating the execution of task components into two scheduling levels, one level for scheduling the task mandatory components by means of a hard real-time policy and another level for scheduling the task optional components by means of a sort of utility-based policy. The set of services actually includes both a facility for communicating mandatory and optional components inside an application and a group of mechanisms for explicitly detecting and handling run-time timing exceptions.The proposed framework is also shown to be realizable in practice. In particular, this thesis presents the design and implementation of a real run-time support system which supports all the features proposed by the framework. This run-time system, called Flexible Real-Time Linux (FRTL), has been developed by enhancing the original capabilities of the Real-Time Linux (RT-Linux) operating system. Finally, an exact timing characterization of the FRTL run-time system and actual measurements of its overhead are also provided. The timing characterization allows for the development of a complete feasibility analysis of the entire system, which can be then used for verifying the timing constraints of any FRTL-based application. The overhead measurements show that the FRTL has been designed and implemented very efficiently. Overall, FRTL is shown to be both predictable and efficient, which actually proves that it can be useful in building real flexible real-time systemsThe work presented in this thesis has been developed in the context of the following rei ii ABSTRACT search projects, which have been funded by the Spanish government: "Entornos de sistemas basados en el conocimiento de tiempo real" (TAP94-0511-C02-01), "ARTIS: herramienta para el desarrollo de sistemas inteligentes en tie...

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HARTIK 3.0: a portable system for developing real-time applications

Cited by 20 publications

References 14 publications

Elastic scheduling for flexible workload management

Elastic scheduling for flexible workload management

Resource Reservation in Dynamic Real-Time Systems

Flexible Real-Time Linux a New Environment for Flexible Hard Real-Time Systems

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