| 1. |
- Bohlin, Markus, et al.
(författare)
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Safe Shared Stack Bounds in Systems with Offsets and Precedences
- 2008
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The paper presents two novel methods to bound the stack memory used in preemptive, shared stack, real-time systems. The first method is based on branch-and-bound search for possible preemption patterns, and the second one approximates the first in polynomial time. The work extends previous methods by considering a more general taskmodel, in which all tasks can share the same stack. In addition, the new methods account for precedence and offset relations. Thus, the methods give tight bounds for a large set of realistic systems. The methods have been implemented and a comprehensive evaluation, comparing our new methods against each other and against existing methods, is presented. The evaluation shows that our exact method can significantly reduce the amount of stack memory needed. In our simulations, a decrease in the order of 40% was typical, with a runtime in the order of seconds. Our polynomial approximation consequently yields about 20% higher bound than the exact method.
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| 2. |
- Hänninen, Kaj
(författare)
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Efficient Memory Utilization in Resource Constrained Real-Time Systems
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis presents design and run-time techniques for efficient memory utilization in embedded real-time systems. The proposed techniques give developers means to reduce the memory consumption in the systems. Altogether, this gives possibilities to increases the added value of industrial systems, in the sense that more features can be fitted on existing hardware.The thesis begins by presenting the results of a series of interviews concerning common requirements in development of embedded real-time systems. Based on these results, the thesis presents a novel component model for development of resource constrained real-time systems. The model supports efficient memory usage through stack sharing and is formal enough to enable predictability of the resulting stack usage. To provide run-time support for stack sharing, the thesis presents an integration of the stack sharing strategy in an operating system for the component model. To determine the resulting memory usage under stack sharing, a novel analysis method is presented. In an evaluation, the thesis show that the analysis method is both fast and that it gives tight bounds on the resulting stack usage, which makes it suitable for industrial use. The thesis ends with a presentation showing the integration of the proposed analysis technique in an integrated development environment.The proposed techniques have been integrated in the commercial tool Rubus-ICE from Arcticus Systems. The techniques will be available for developers in the upcoming release of Rubus-ICE.
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| 3. |
- Hänninen, Kaj, 1970-
(författare)
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Introducing a Memory Efficient Execution Model in a Tool-Suite for Real-Time Systems
- 2006
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis shows how development of embedded real-time systems can be made more efficient by introduction of an memory efficient execution model in a commercial development suite. To identify the need of additional support for execution models in development tools, the thesis investigate by a series of interviews, the common requirements in development of industrial embedded real-time systems. The results indicate that there exist functionality in industrial systems that could be more efficiently implemented in other execution models than the currently supported ones. The thesis then presents how use of multiple execution models (hybrid scheduling) can reduce processor utilization in real-world applications. Furthermore, the thesis presents an integration of an memory efficient execution model in an industrially used real-time operating system. In addition, the thesis describes an efficient technique to analyze memory consumptions of functionality executing under the introduced execution model.Embedded computers play an important role in peoples everyday life. Nowadays, we can find computers in product such as microwave ovens, washing machines, DVD players, cellular phones and cars, to mention a few examples. For example, a modern car may have more than 70 embedded control units handling functionality such as airbags, anti-lock braking, traction control etc. In addition, there is a clear trend indicating that the amount of computer controlled functionality in products will continue to increase. Many of today’s embedded systems are resource constrained and the software for them is developed for a few execution models. Even though researchers has proposed a numerous number of different execution models for embedded real-time systems, in practice however, only a few of the proposed execution models are supported in industrial development tools. This implies that developers often force fit functionality to be executed under these models, resulting in poor resource utilization and increasing complexity in software.
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| 4. |
- Hänninen, Kaj, et al.
(författare)
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Introducing a Plug-In Framework for Real-Time Analysis in Rubus-ICE
- 2008
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- In this paper, we present the development of a plug-in framework for integration of real-time analysis methods in the Rubus Integrated Component Environment (Rubus-ICE). We also present the implementation, and evaluate the integration, of two state of the art analysis techniques (i) response-time analysis for tasks with offsets and (ii) shared stack analysis, as plug-ins, in the Rubus-ICE framework.The paper shows that the proposed framework is well suited for integration of complex analysis methods. However, experience also show that analysis methods are not easily transferred from an academic environment to industry. The main reason for this, we believe, originates from differences in requirements and assumptions between industry and academia.
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| 5. |
- Hänninen, Kaj, et al.
(författare)
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Supporting Engineering Requirements in the Rubus Component Model
- 2008
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- In this paper we present a component model for development of distributed real-time systems.The model is developed to support development of embedded control systems for ground vehicles. The model aims at supporting three important activities in real-time development, (i) design, (ii) analysis and (iii) synthesis. These activities emphasise different and sometimes conflicting requirements that need to be balanced. For example, developers desire freedom in designing to solve complex tasks, analysis tools require the design to be formal enough for analysis and synthesis need to be efficient for low run-time footprint. We have considered industrial requirements for these activities and developed the RubusCMv3 component model. The model has been developed in close cooperation with industrial partners and it is currently being evaluated on real systems.
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| 6. |
- Mäki-Turja, Jukka, et al.
(författare)
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Efficient Development of Real-Time Systems Using Hybrid Scheduling
- 2005
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Ingår i: Proceedings of the 2005 International Conference on Embedded Systems and Applications, ESA'05. - 9781932415537 ; , s. 53-59
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- This paper will show how advanced embedded realtime systems, with functionality ranging from time-triggered control functionality to event-triggered user interaction, can be made more efficient. Efficient with respect to development effort as well as run-time resource utilization. This is achieved by using a hybrid, static and dynamic, scheduling strategy. The approach is applicable even for hard real-time systems since tight response time guarantees can be given by the response time analysis method for tasks with offsets. An industrial case study will demonstrate how this approach enables more efficient use of computational resources, resulting in a cheaper or more competitive product since more functionality can be fitted into legacy, resource constrained, hardware.
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