| 1. |
- Axer, Philip, et al.
(författare)
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Building Timing Predictable Embedded Systems
- 2012
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- A large class of embedded systems is distinguished from general purpose computing systems by the need to satisfy strict requirements on timing, often under constraints on available resources. Predictable system design is concerned with the challenge of building systems for which timing requirements can be guaranteed a priori. Perhaps paradoxically, this problem has become more difficult by the introduction of performance-enhancing architectural elements, such as caches, pipelines, and multithreading, which introduce a large degree of nondeterminism and make guarantees harder to provide. The intention of this paper is to summarize current state-of-the-art in research concerning how to build predictable yet performant systems. We suggest precise definitions for the concept of “predictability”, and present predictability concerns at different abstractions levels in embedded software design. First, we consider timing predictability of processor instruction sets. Thereafter, We consider how programming languages can be equipped with predictable timing semantics, covering both a language-based approach based on the synchronous paradigm, as well as an environment that provides timing semantics for a mainstream programming language (in this case C). We present techniques for achieving timing predictability on multicores. Finally we discuss how to handle predictability at the level of networked embedded systems, where randomly occurring errors must be considered.
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| 2. |
- Fuhrmann, Insa, et al.
(författare)
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Time for Reactive System Modeling : Interactive Timing Analysis with Hotspot Highlighting
- 2016
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Ingår i: In Proceedings of the 24th International Conference on Real-Time Networks and Systems (RTNS 2016). - New York, NY, USA : ACM Press. - 9781450347877
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Konferensbidrag (refereegranskat)abstract
- Modeling tools typically provide no information about timing properties and costly parts of the system under development. In this paper we propose a generic approach to integrate timing analysis and modeling tools. This approach includes visual highlighting to guide the user to worst-case execution time hotspots, detailed timing information for specific model elements, and the separation of di↵erent types of timing val- ues. Our solution includes both a way to keep track of model elements subject to timing analysis during the compilation process, and a flexible and formally defined timing analysis interface for communicating timing information between a high-level modeling tool and a lower-level timing analysis tool. We present a complete open-source, Eclipse-based pro- totype tool chain that is evaluated both using a systematic benchmark suite and a user study.
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| 3. |
- Fuhrmann, Insa, et al.
(författare)
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Towards Interactive Timing Analysis for Designing Reactive Systems
- 2014
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Reactive systems are increasingly developed using high-level modeling tools. Such modeling tools may facilitate formal reasoning about concurrent programs, but provide little help when timing-related problems arise and deadlines are missed when running a real system. In these cases, the modeler has typically no information about timing properties and costly parts of the model; there is little or no guidance on how to improve the timing characteristics of the model. In this paper, we propose a design methodology where interactive timing analysis is an integral part of the modeling process. This methodology concerns how to aggregate timing values in a user-friendly manner and how to define timing analysis requests. We also introduce and formalize a new timing analysis interface that is designed for communicating timing information between a high-level modeling tool and a lower-level timing analysis tool.
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| 4. |
- Ungureanu, George
(författare)
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ForSyDe-Atom: Design of Heterogeneous Embedded Systems : Taming Complexity with Layers, Atoms and Patterns
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The design of embedded systems is inherently complex for two main reasons. Firstly, it entails the combined knowledge and results from a vast set of mature, well-established, yet separate disciplines, such as electrical engineering, computer science, mechanical engineering, etc. Secondly, it needs to account for the collective behavior of computing elements, infrastructure and physical environment. This behavior cannot be derived from the sum of its constituent components, rather it emerges from the manifold feedback interactions between them. One of the main tools that have enabled engineers to guide the development of systems with unprecedented complexity is abstraction, that is, capturing essential properties of phenomena into mathematical, well-behaved analyzable models. Yet combining models from different disciplines is largely limited due to the fact that these models, although well-acknowledged, are most often incompatible. In a system design process, this leads to the discovery and understanding of unwanted or hazardous behaviors during later stages such as prototyping or deployment phases, when design reiterations are extremely costly.This thesis introduces ForSyDe-Atom, a formal framework intended as an entry point for the disciplined design of embedded systems. This framework provides a set of rules for combining several domain specific languages as structured, enclosing layers in order to orthogonalize the many aspects of system behavior, yet study their interaction in tandem. It enables systematic exploitation of design properties in a system design flow by facilitating the step-wise projection of certain layers of interest, the isolated analysis and refinement on projections and the seamless reconstruction of a system model from (possibly refined) projections. As examples of languages hosted by this framework, five layers are presented: one for capturing timed interactions in heterogeneous systems, one for extending behaviors with controlled effects, one for structured parallelism, one for modeling uncertainty and one for describing component properties. The modeling capabilities are demonstrated through numerous didactic examples and four large case studies from the application domains of digital signal processing and avionics. A set of strategies for parallelizing timed simulation models, together with a preliminary component-based synthesis flow towards embedded platforms further highlight the potential of this framework as an entry point to system design.
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| 5. |
- von Hanxleden, Reinhard, et al.
(författare)
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WCET Tool Challenge 2011: Report
- 2011
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Ingår i: Proc. 11th International Workshop on Worst-Case Execution Time (WCET) Analysis (WCET 2011). - 9781632663153 ; , s. 104-138
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Konferensbidrag (refereegranskat)abstract
- Following the successful WCET Tool Challenges in 2006 and 2008, the third event in this series was organized in 2011, again with support from the ARTIST DESIGN Network of Excellence. Following the practice established in the previous Challenges, the WCET Tool Challenge 2011 (WCC'11) defined two kinds of problems to be solved by the Challenge participants with their tools, WCET problems, which ask for bounds on the execution time, and flow-analysis problems, which ask for bounds on the number of times certain parts of the code can be executed. The benchmarks to be used in WCC'11 were debie1, PapaBench, and an industrial-strength application from the automotive domain provided by Daimler. Two default execution platforms were suggested to the participants, the ARM7 as "simple target" and the MPC5553/5554 as a "complex target", but participants were free to use other platforms as well. Ten tools participated in WCC'11: aiT, AstrEe, Bound-T, FORTAS, METAMOC, OTAWA, SWEET, TimeWeaver, TuBound and WCA.
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