Volume
OASIcs, Volume 8
8th International Workshop on Worst-Case Execution Time Analysis (WCET'08)
-
Part of:
Series:
Open Access Series in Informatics (OASIcs)
Conference: Workshop on Worst-Case Execution Time Analysis (WCET)
Event
WCET 2008, July 1, 2008, Prague, Czech RepublicEditor
Publication Details
- published at: 2008-11-13
- Publisher: Schloss Dagstuhl – Leibniz-Zentrum für Informatik
- ISBN: 978-3-939897-10-1
- DBLP: db/conf/wcet/wcet2008
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Complete Volume
OASIcs, Volume 8, WCET'08, Complete Volume
Abstract
OASIcs, Volume 8, WCET'08, Complete Volume
Cite as
8th International Workshop on Worst-Case Execution Time Analysis (WCET'08). Open Access Series in Informatics (OASIcs), Volume 8, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2012)
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@Proceedings{kirner:OASIcs.WCET.2008,
title = {{OASIcs, Volume 8, WCET'08, Complete Volume}},
booktitle = {8th International Workshop on Worst-Case Execution Time Analysis (WCET'08)},
series = {Open Access Series in Informatics (OASIcs)},
ISBN = {978-3-939897-10-1},
ISSN = {2190-6807},
year = {2012},
volume = {8},
editor = {Kirner, Raimund},
publisher = {Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
address = {Dagstuhl, Germany},
URL = {https://drops-dev.dagstuhl.de/entities/document/10.4230/OASIcs.WCET.2008},
URN = {urn:nbn:de:0030-drops-35701},
doi = {10.4230/OASIcs.WCET.2008},
annote = {Keywords: Performance of Systems, Software/Program Verification}
}
Document
Front Matter
WCET 2008 Abstracts Collection -- 8th Intl. Workshop on Worst-Case Execution Time (WCET) Analysis
Abstract
The workshop on Worst-Case Execution Time Analysis is a satellite event to
the annual Euromicro Conference on Real-Time Systems. It brings together
people that are interested in all aspects of timing analysis for real-time
systems. In the 2008 edition, 13 papers were presented, organized into four
sessions: methods for WCET computation, low-level analysis, system-level
analysis and flow-analysis. The workshop was also the opportunity to report
from the 2007 WCET tool challenge.
Cite as
8th International Workshop on Worst-Case Execution Time Analysis (WCET'08). Open Access Series in Informatics (OASIcs), Volume 8, pp. i-x, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2008)
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@InProceedings{kirner:OASIcs.WCET.2008.1671,
author = {Kirner, Raimund},
title = {{WCET 2008 Abstracts Collection -- 8th Intl. Workshop on Worst-Case Execution Time (WCET) Analysis}},
booktitle = {8th International Workshop on Worst-Case Execution Time Analysis (WCET'08)},
pages = {i--x},
series = {Open Access Series in Informatics (OASIcs)},
ISBN = {978-3-939897-10-1},
ISSN = {2190-6807},
year = {2008},
volume = {8},
editor = {Kirner, Raimund},
publisher = {Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
address = {Dagstuhl, Germany},
URL = {https://drops-dev.dagstuhl.de/entities/document/10.4230/OASIcs.WCET.2008.1671},
URN = {urn:nbn:de:0030-drops-16712},
doi = {10.4230/OASIcs.WCET.2008.1671},
annote = {Keywords: Worst-case execution time, real-time systems, timing analysis}
}
Document
WCET 2008 -- Report from the Tool Challenge 2008 -- 8th Intl. Workshop on Worst-Case Execution Time (WCET) Analysis
Abstract
Following the successful WCET Tool Challenge in 2006, the second event in this series was organized in 2008, again with support from the ARTIST2 Network of Excellence. The WCET Tool Challenge 2008 (WCC'08) provides benchmark programs and poses a number of "analysis problems" about the dynamic, run-time properties of these programs. The participants are challenged to solve these problems with their program analysis tools. Two kinds of problems are defined: WCET problems, which ask for bounds on the execution time of chosen parts (subprograms) of the benchmarks, under given constraints on input data; and flow-analysis problems, which ask for bounds on the number of times certain parts of the benchmark can be executed, again under some constraints. We describe the organization of WCC'08, the benchmark programs, the participating tools, and the general results, successes, and failures. Most participants found WCC'08 to be a useful test of their tools. Unlike the 2006 Challenge, the WCC'08 participants include several tools for the same target (ARM7, LPC2138), and tools that combine measurements and static analysis, as well as pure static-analysis tools.
Cite as
Niklas Holsti, Jan Gustafsson, Guillem Bernat, Clément Ballabriga, Armelle Bonenfant, Roman Bourgade, Hugues Cassé, Daniel Cordes, Albrecht Kadlec, Raimund Kirner, Jens Knoop, Paul Lokuciejewski, Nicholas Merriam, Marianne de Michiel, Adrian Prantl, Bernhard Rieder, Christine Rochange, Pascal Sainrat, and Markus Schordan. WCET 2008 -- Report from the Tool Challenge 2008 -- 8th Intl. Workshop on Worst-Case Execution Time (WCET) Analysis. In 8th International Workshop on Worst-Case Execution Time Analysis (WCET'08). Open Access Series in Informatics (OASIcs), Volume 8, pp. 1-23, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2008)
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@InProceedings{holsti_et_al:OASIcs.WCET.2008.1663,
author = {Holsti, Niklas and Gustafsson, Jan and Bernat, Guillem and Ballabriga, Cl\'{e}ment and Bonenfant, Armelle and Bourgade, Roman and Cass\'{e}, Hugues and Cordes, Daniel and Kadlec, Albrecht and Kirner, Raimund and Knoop, Jens and Lokuciejewski, Paul and Merriam, Nicholas and de Michiel, Marianne and Prantl, Adrian and Rieder, Bernhard and Rochange, Christine and Sainrat, Pascal and Schordan, Markus},
title = {{WCET 2008 -- Report from the Tool Challenge 2008 -- 8th Intl. Workshop on Worst-Case Execution Time (WCET) Analysis}},
booktitle = {8th International Workshop on Worst-Case Execution Time Analysis (WCET'08)},
pages = {1--23},
series = {Open Access Series in Informatics (OASIcs)},
ISBN = {978-3-939897-10-1},
ISSN = {2190-6807},
year = {2008},
volume = {8},
editor = {Kirner, Raimund},
publisher = {Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
address = {Dagstuhl, Germany},
URL = {https://drops-dev.dagstuhl.de/entities/document/10.4230/OASIcs.WCET.2008.1663},
URN = {urn:nbn:de:0030-drops-16637},
doi = {10.4230/OASIcs.WCET.2008.1663},
annote = {Keywords: WCET analysis, benchmark}
}
Document
A tool for average and worst-case execution time analysis
Abstract
We have developed a new programming paradigmwhich, for conforming programs, allows the average-case execution time (ACET) to be obtained automatically by a static analysis. This is achieved by tracking the data structures and their distributions that will exist during all possible executions of a program. This new programming paradigm is called MOQA and the tool which performs the static analysis is called Distritrack. In this paper we give an overview of both MOQA and Distritrack. We then discuss the possibility of extending Distritrack for static worst-case execution time (WCET) analysis ofMOQA programs using the tight tracking of data structures already being performed.
The authors wish to acknowledge the support of SFI grant SFI 02/IN.1/I181.
Cite as
David Hickey, Diarmuid Early, and Michel Schellekens. A tool for average and worst-case execution time analysis. In 8th International Workshop on Worst-Case Execution Time Analysis (WCET'08). Open Access Series in Informatics (OASIcs), Volume 8, pp. 1-12, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2008)
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@InProceedings{hickey_et_al:OASIcs.WCET.2008.1668,
author = {Hickey, David and Early, Diarmuid and Schellekens, Michel},
title = {{A tool for average and worst-case execution time analysis}},
booktitle = {8th International Workshop on Worst-Case Execution Time Analysis (WCET'08)},
pages = {1--12},
series = {Open Access Series in Informatics (OASIcs)},
ISBN = {978-3-939897-10-1},
ISSN = {2190-6807},
year = {2008},
volume = {8},
editor = {Kirner, Raimund},
publisher = {Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
address = {Dagstuhl, Germany},
URL = {https://drops-dev.dagstuhl.de/entities/document/10.4230/OASIcs.WCET.2008.1668},
URN = {urn:nbn:de:0030-drops-16680},
doi = {10.4230/OASIcs.WCET.2008.1668},
annote = {Keywords: Tool, static timing, worst-case, average-case, execution time}
}
Document
Applying WCET Analysis at Architectural Level
Abstract
Real-Time embedded systems must enforce strict timing constraints. In this context, achieving precise Worst Case Execution Time is a prerequisite to apply scheduling analysis and verify system viability.
WCET analysis is usually a complex and time-consuming activity. It becomes increasingly complex when one also considers code generation strategies from high-level models. In this paper, we present an experiment made on the coupling of the WCET analysis tool Bound-T and our AADL to code generator OCARINA. We list the different steps to successfully apply WCET analysis directly from model, to limit user intervention.
Cite as
Olivier Gilles and Jérôme Hugues. Applying WCET Analysis at Architectural Level. In 8th International Workshop on Worst-Case Execution Time Analysis (WCET'08). Open Access Series in Informatics (OASIcs), Volume 8, pp. 1-9, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2008)
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@InProceedings{gilles_et_al:OASIcs.WCET.2008.1665,
author = {Gilles, Olivier and Hugues, J\'{e}r\^{o}me},
title = {{Applying WCET Analysis at Architectural Level}},
booktitle = {8th International Workshop on Worst-Case Execution Time Analysis (WCET'08)},
pages = {1--9},
series = {Open Access Series in Informatics (OASIcs)},
ISBN = {978-3-939897-10-1},
ISSN = {2190-6807},
year = {2008},
volume = {8},
editor = {Kirner, Raimund},
publisher = {Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
address = {Dagstuhl, Germany},
URL = {https://drops-dev.dagstuhl.de/entities/document/10.4230/OASIcs.WCET.2008.1665},
URN = {urn:nbn:de:0030-drops-16653},
doi = {10.4230/OASIcs.WCET.2008.1665},
annote = {Keywords: WCET, AADL, Bound-T, Ocarina}
}
Document
Computing time as a program variable: a way around infeasible paths
Abstract
Conditional branches connect the values of program variables with the execution paths and thus with the execution times, including the worst-case execution time (WCET). Flow analysis aims to discover this connection and represent it as loop bounds and other path constraints. Usually, a specific analysis of the dependencies between branch conditions and assignments to variables creates some representation of the feasible paths, for example as IPET execution-count constraints, from which a WCET bound is calculated. This paper explores another approach that uses a more direct connection between variable values and execution time. The execution time is modeled as a program variable. An analysis of the dependencies between variables, including the execution-time variable, gives a WCET bound that excludes many infeasible paths. Examples show that the approach often works, in principle. It remains to be seen if it is scalable to real programs.
Cite as
Niklas Holsti. Computing time as a program variable: a way around infeasible paths. In 8th International Workshop on Worst-Case Execution Time Analysis (WCET'08). Open Access Series in Informatics (OASIcs), Volume 8, pp. 1-11, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2008)
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@InProceedings{holsti:OASIcs.WCET.2008.1660,
author = {Holsti, Niklas},
title = {{Computing time as a program variable: a way around infeasible paths}},
booktitle = {8th International Workshop on Worst-Case Execution Time Analysis (WCET'08)},
pages = {1--11},
series = {Open Access Series in Informatics (OASIcs)},
ISBN = {978-3-939897-10-1},
ISSN = {2190-6807},
year = {2008},
volume = {8},
editor = {Kirner, Raimund},
publisher = {Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
address = {Dagstuhl, Germany},
URL = {https://drops-dev.dagstuhl.de/entities/document/10.4230/OASIcs.WCET.2008.1660},
URN = {urn:nbn:de:0030-drops-16608},
doi = {10.4230/OASIcs.WCET.2008.1660},
annote = {Keywords: WCET, flow analysis, infeasible paths, dependency analysis}
}
Document
Improving the WCET computation time by IPET using control flow graph partitioning
Abstract
Implicit Path Enumeration Technique (IPET) is currently largely used to compute Worst Case Execution Time (WCET) by modeling control flow and architecture using integer linear programming (ILP). As precise architecture effects requires a lot of constraints, the super-linear complexity of the ILP solver makes computation times bigger and bigger. In this paper, we propose to split the control flow of the program into smaller parts where a local WCET can be computed faster - as the resulting ILP system is smaller - and to combine these local results to get the overall WCET without loss of precision. The experimentation in our tool OTAWA with lp_solve solver has shown an average computation improvement of 6.5 times.
Cite as
Clément Ballabriga and Hugues Cassé. Improving the WCET computation time by IPET using control flow graph partitioning. In 8th International Workshop on Worst-Case Execution Time Analysis (WCET'08). Open Access Series in Informatics (OASIcs), Volume 8, pp. 1-9, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2008)
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@InProceedings{ballabriga_et_al:OASIcs.WCET.2008.1670,
author = {Ballabriga, Cl\'{e}ment and Cass\'{e}, Hugues},
title = {{Improving the WCET computation time by IPET using control flow graph partitioning}},
booktitle = {8th International Workshop on Worst-Case Execution Time Analysis (WCET'08)},
pages = {1--9},
series = {Open Access Series in Informatics (OASIcs)},
ISBN = {978-3-939897-10-1},
ISSN = {2190-6807},
year = {2008},
volume = {8},
editor = {Kirner, Raimund},
publisher = {Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
address = {Dagstuhl, Germany},
URL = {https://drops-dev.dagstuhl.de/entities/document/10.4230/OASIcs.WCET.2008.1670},
URN = {urn:nbn:de:0030-drops-16701},
doi = {10.4230/OASIcs.WCET.2008.1670},
annote = {Keywords: Static analysis, SESE regions, ILP}
}
Document
INFER: Interactive Timing Profiles based on Bayesian Networks
Abstract
We propose an approach for timing analysis of software-based embedded computer systems that builds on the established probabilistic framework of Bayesian networks. We envision an approach where we take (1) an abstract description of the control flow within a piece of software, and (2) a set of run-time traces, which are combined into a Bayesian network that can be seen as an interactive timing profile. The obtained profile can be used by the embedded systems engineer not only to obtain a probabilistic estimate of the WCET, but also to run interactive timing simulations, or to automatically identify software configurations that are likely to evoke noteworthy timing behavior, like, e.g., high variances of execution times, and which are therefore candidates for further inspection.
Cite as
Michael Zolda. INFER: Interactive Timing Profiles based on Bayesian Networks. In 8th International Workshop on Worst-Case Execution Time Analysis (WCET'08). Open Access Series in Informatics (OASIcs), Volume 8, pp. 1-13, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2008)
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@InProceedings{zolda:OASIcs.WCET.2008.1669,
author = {Zolda, Michael},
title = {{INFER: Interactive Timing Profiles based on Bayesian Networks}},
booktitle = {8th International Workshop on Worst-Case Execution Time Analysis (WCET'08)},
pages = {1--13},
series = {Open Access Series in Informatics (OASIcs)},
ISBN = {978-3-939897-10-1},
ISSN = {2190-6807},
year = {2008},
volume = {8},
editor = {Kirner, Raimund},
publisher = {Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
address = {Dagstuhl, Germany},
URL = {https://drops-dev.dagstuhl.de/entities/document/10.4230/OASIcs.WCET.2008.1669},
URN = {urn:nbn:de:0030-drops-16695},
doi = {10.4230/OASIcs.WCET.2008.1669},
annote = {Keywords: Bayesian networks, embedded systems, hardware modeling, measurement-based execution time analysis, software modeling, probabilistic modeling, profilin}
}
Document
Merging Techniques for Faster Derivation of WCET Flow Information using Abstract Execution
Abstract
Static Worst-Case Execution Time (WCET) analysis derives upper bounds for the execution times of programs. Such bounds are crucial when designing and verifying real-time systems. A key component in static WCET analysis is to derive flow information, such as loop bounds and infeasible paths. We have previously introduced abstract execution (AE), a method capable of deriving very precise flow information. This paper present different merging techniques that can be used by AE for trading analysis time for flow information precision. It also presents a new technique, ordered merging, which may radically shorten AE analysis times, especially when analyzing large programs with many possible input variable values.
Cite as
Jan Gustafsson and Andreas Ermedahl. Merging Techniques for Faster Derivation of WCET Flow Information using Abstract Execution. In 8th International Workshop on Worst-Case Execution Time Analysis (WCET'08). Open Access Series in Informatics (OASIcs), Volume 8, pp. 1-11, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2008)
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@InProceedings{gustafsson_et_al:OASIcs.WCET.2008.1658,
author = {Gustafsson, Jan and Ermedahl, Andreas},
title = {{Merging Techniques for Faster Derivation of WCET Flow Information using Abstract Execution}},
booktitle = {8th International Workshop on Worst-Case Execution Time Analysis (WCET'08)},
pages = {1--11},
series = {Open Access Series in Informatics (OASIcs)},
ISBN = {978-3-939897-10-1},
ISSN = {2190-6807},
year = {2008},
volume = {8},
editor = {Kirner, Raimund},
publisher = {Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
address = {Dagstuhl, Germany},
URL = {https://drops-dev.dagstuhl.de/entities/document/10.4230/OASIcs.WCET.2008.1658},
URN = {urn:nbn:de:0030-drops-16585},
doi = {10.4230/OASIcs.WCET.2008.1658},
annote = {Keywords: Worst-Case Execution Time (WCET) analysis, flow analysis}
}
Document
On Composable System Timing, Task Timing, and WCET Analysis
Abstract
The complexity of hardware and software architectures used in today's
embedded systems make a hierarchical, composable timing analysis
impossible. This paper describes the source of this complexity in
terms of mechanisms and side effects that determine variations in the
timing of single tasks and entire applications. Based on these
observations, the paper proposes strategies to reduce the complexity.
It shows the positive effects of these strategies on the timing of
tasks and on WCET analysis.
Cite as
Peter Puschner and Martin Schoeberl. On Composable System Timing, Task Timing, and WCET Analysis. In 8th International Workshop on Worst-Case Execution Time Analysis (WCET'08). Open Access Series in Informatics (OASIcs), Volume 8, pp. 1-11, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2008)
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@InProceedings{puschner_et_al:OASIcs.WCET.2008.1662,
author = {Puschner, Peter and Schoeberl, Martin},
title = {{On Composable System Timing, Task Timing, and WCET Analysis}},
booktitle = {8th International Workshop on Worst-Case Execution Time Analysis (WCET'08)},
pages = {1--11},
series = {Open Access Series in Informatics (OASIcs)},
ISBN = {978-3-939897-10-1},
ISSN = {2190-6807},
year = {2008},
volume = {8},
editor = {Kirner, Raimund},
publisher = {Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
address = {Dagstuhl, Germany},
URL = {https://drops-dev.dagstuhl.de/entities/document/10.4230/OASIcs.WCET.2008.1662},
URN = {urn:nbn:de:0030-drops-16622},
doi = {10.4230/OASIcs.WCET.2008.1662},
annote = {Keywords: Real-time systems, timing analysis, WCET analysis, predictable timing, composability}
}
Document
Towards a Common WCET Annotation Language: Essential Ingredients
Abstract
Within the last years, ambitions towards the definition of common
interfaces and the development of open frameworks have increased the
efficiency of research on WCET analysis. The Annotation
Language Challenge for WCET analysis has been proposed in
line with these ambitions in order to push the development of common
interfaces also to the level of annotation languages, which are
crucial for the power of WCET analysis tools.
In this paper we present a list of essential ingredients for a
common WCET annotation language. The selected ingredients comprise
a number of features available in different WCET analysis tools and
add several new concepts we consider important. The annotation
concepts are described in an abstract format that can be
instantiated at different representation levels.
Cite as
Raimund Kirner, Albrecht Kadlec, Adrian Prantl, Markus Schordan, and Jens Knoop. Towards a Common WCET Annotation Language: Essential Ingredients. In 8th International Workshop on Worst-Case Execution Time Analysis (WCET'08). Open Access Series in Informatics (OASIcs), Volume 8, pp. 1-13, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2008)
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@InProceedings{kirner_et_al:OASIcs.WCET.2008.1657,
author = {Kirner, Raimund and Kadlec, Albrecht and Prantl, Adrian and Schordan, Markus and Knoop, Jens},
title = {{Towards a Common WCET Annotation Language: Essential Ingredients}},
booktitle = {8th International Workshop on Worst-Case Execution Time Analysis (WCET'08)},
pages = {1--13},
series = {Open Access Series in Informatics (OASIcs)},
ISBN = {978-3-939897-10-1},
ISSN = {2190-6807},
year = {2008},
volume = {8},
editor = {Kirner, Raimund},
publisher = {Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
address = {Dagstuhl, Germany},
URL = {https://drops-dev.dagstuhl.de/entities/document/10.4230/OASIcs.WCET.2008.1657},
URN = {urn:nbn:de:0030-drops-16575},
doi = {10.4230/OASIcs.WCET.2008.1657},
annote = {Keywords: Worst-case execution time (WCET) analysis, annotation languages, WCET annotation language challenge}
}
Document
Towards an Automatic Parametric WCET Analysis
Abstract
Static WCET analysis obtains a safe estimation of the WCET of a program. The timing behaviour of a program depends in many cases on input, and an analysis could take advantage of this information to produce a formula in input variables as estimation of the WCET, rather than a constant. A method to do this was suggested in [12]. We have implemented a working prototype of the method to evaluate its feasibility in practice. We show how to reduce complexity of the method and how to simplify parts of it to make it practical for implementation. The prototype implementation indicates that the method presented in [12] successfully can be implemented for a simple imperative language, mostly by using
existing libraries.
Cite as
Stefan Bygde and Björn Lisper. Towards an Automatic Parametric WCET Analysis. In 8th International Workshop on Worst-Case Execution Time Analysis (WCET'08). Open Access Series in Informatics (OASIcs), Volume 8, pp. 1-9, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2008)
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@InProceedings{bygde_et_al:OASIcs.WCET.2008.1659,
author = {Bygde, Stefan and Lisper, Bj\"{o}rn},
title = {{Towards an Automatic Parametric WCET Analysis}},
booktitle = {8th International Workshop on Worst-Case Execution Time Analysis (WCET'08)},
pages = {1--9},
series = {Open Access Series in Informatics (OASIcs)},
ISBN = {978-3-939897-10-1},
ISSN = {2190-6807},
year = {2008},
volume = {8},
editor = {Kirner, Raimund},
publisher = {Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
address = {Dagstuhl, Germany},
URL = {https://drops-dev.dagstuhl.de/entities/document/10.4230/OASIcs.WCET.2008.1659},
URN = {urn:nbn:de:0030-drops-16592},
doi = {10.4230/OASIcs.WCET.2008.1659},
annote = {Keywords: WCET, Flow Analysis, Parametric, Symbolic}
}
Document
Towards Predicated WCET Analysis
Abstract
In this paper, we propose the use of constraint logic programming as a way of modeling context-sensitive execution-times of program segments. The context-sensitive constraints are collected automatically through static analysis or measurements. We achieve considerable tightness in comparison to traditional calculation methods that exceeded 20% in some cases during evaluation. The use of constraint-logic programming in our calculations proves to be the right choice when compared to the exponential behaviour recorded by the use of integer linear-programming.
Cite as
Amine Marref and Guillem Bernat. Towards Predicated WCET Analysis. In 8th International Workshop on Worst-Case Execution Time Analysis (WCET'08). Open Access Series in Informatics (OASIcs), Volume 8, pp. 1-10, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2008)
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@InProceedings{marref_et_al:OASIcs.WCET.2008.1667,
author = {Marref, Amine and Bernat, Guillem},
title = {{Towards Predicated WCET Analysis}},
booktitle = {8th International Workshop on Worst-Case Execution Time Analysis (WCET'08)},
pages = {1--10},
series = {Open Access Series in Informatics (OASIcs)},
ISBN = {978-3-939897-10-1},
ISSN = {2190-6807},
year = {2008},
volume = {8},
editor = {Kirner, Raimund},
publisher = {Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
address = {Dagstuhl, Germany},
URL = {https://drops-dev.dagstuhl.de/entities/document/10.4230/OASIcs.WCET.2008.1667},
URN = {urn:nbn:de:0030-drops-16670},
doi = {10.4230/OASIcs.WCET.2008.1667},
annote = {Keywords: WCET Analysis, Implicit-Path Enumeration-Technique, Constraint-Logic Programming, Static Analysis}
}
Document
Traces as a Solution to Pessimism and Modeling Costs in WCET Analysis
Abstract
WCET analysis models for superscalar out-of-order CPUs
generally need to be pessimistic in order to account for
a wide range of possible dynamic behavior. CPU hardware modifications
could be used to constrain operations to known execution paths
called traces, permitting exploitation of instruction
level parallelism with guaranteed
timing. Previous implementations of traces have used
microcode to constrain operations, but other possibilities
exist. A new implementation strategy (virtual
traces) is introduced here.
In this paper the benefits and costs of traces are discussed.
Advantages of traces include a reduction in pessimism in WCET analysis,
with the need to accurately model CPU internals removed. Disadvantages
of traces include a reduction of peak throughput of the CPU, a need
for deterministic memory and a potential increase in the complexity
of WCET models.
Cite as
Jack Whitham and Neil Audsley. Traces as a Solution to Pessimism and Modeling Costs in WCET Analysis. In 8th International Workshop on Worst-Case Execution Time Analysis (WCET'08). Open Access Series in Informatics (OASIcs), Volume 8, pp. 1-8, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2008)
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@InProceedings{whitham_et_al:OASIcs.WCET.2008.1666,
author = {Whitham, Jack and Audsley, Neil},
title = {{Traces as a Solution to Pessimism and Modeling Costs in WCET Analysis}},
booktitle = {8th International Workshop on Worst-Case Execution Time Analysis (WCET'08)},
pages = {1--8},
series = {Open Access Series in Informatics (OASIcs)},
ISBN = {978-3-939897-10-1},
ISSN = {2190-6807},
year = {2008},
volume = {8},
editor = {Kirner, Raimund},
publisher = {Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
address = {Dagstuhl, Germany},
URL = {https://drops-dev.dagstuhl.de/entities/document/10.4230/OASIcs.WCET.2008.1666},
URN = {urn:nbn:de:0030-drops-16666},
doi = {10.4230/OASIcs.WCET.2008.1666},
annote = {Keywords: WCET superscalar cpu virtual traces}
}
Document
TuBound - A Conceptually New Tool for Worst-Case Execution Time Analysis
Abstract
TuBound is a conceptually new tool for the worst-case execution time (WCET) analysis of programs. A distinctive feature of TuBound is the seamless integration of a WCET analysis component and of a compiler in a uniform tool. TuBound enables the programmer to provide hints improving the precision of the WCET computation on the high-level program source code, while preserving the advantages of using an optimizing compiler and the accuracy of a WCET analysis performed on the low-level machine code. This way, TuBound ideally serves the needs of both the programmer and the WCET analysis by providing them the interface on the very abstraction level that is most appropriate and convenient to them.
In this paper we present the system architecture of TuBound, discuss the internal work-flow of the tool, and report on first measurements using benchmarks from Maelardalen University. TuBound took also part in the WCET Tool Challenge 2008.
Cite as
Adrian Prantl, Markus Schordan, and Jens Knoop. TuBound - A Conceptually New Tool for Worst-Case Execution Time Analysis. In 8th International Workshop on Worst-Case Execution Time Analysis (WCET'08). Open Access Series in Informatics (OASIcs), Volume 8, pp. 1-8, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2008)
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@InProceedings{prantl_et_al:OASIcs.WCET.2008.1661,
author = {Prantl, Adrian and Schordan, Markus and Knoop, Jens},
title = {{TuBound - A Conceptually New Tool for Worst-Case Execution Time Analysis}},
booktitle = {8th International Workshop on Worst-Case Execution Time Analysis (WCET'08)},
pages = {1--8},
series = {Open Access Series in Informatics (OASIcs)},
ISBN = {978-3-939897-10-1},
ISSN = {2190-6807},
year = {2008},
volume = {8},
editor = {Kirner, Raimund},
publisher = {Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
address = {Dagstuhl, Germany},
URL = {https://drops-dev.dagstuhl.de/entities/document/10.4230/OASIcs.WCET.2008.1661},
URN = {urn:nbn:de:0030-drops-16611},
doi = {10.4230/OASIcs.WCET.2008.1661},
annote = {Keywords: Worst-case execution time (WCET) analysis, Tool Chain, Flow Constraints, Source-To-Source}
}
Document
WCET Analysis for Preemptive Scheduling
Abstract
Hard real-time systems induce strict constraints on the timing of the task
set. Validation of these timing constraints is thus a major challenge during the
design of such a system. Whereas the derivation of timing guarantees must
already be considered complex if tasks are running to completion, it gets even
more complex if tasks are scheduled preemptively -- especially due to
caches, deployed to improve the average performance. In this paper we propose
a new method to compute valid upper bounds on a task's worst case execution time
(WCET). Our method approximates an optimal memory layout such that
the set of possibly evicted cache-entries during preemption is
minimized. This set then delivers information to bound the execution time of
tasks under preemption in an adopted WCET analysis.
Cite as
Sebastian Altmeyer and Gernot Gebhard. WCET Analysis for Preemptive Scheduling. In 8th International Workshop on Worst-Case Execution Time Analysis (WCET'08). Open Access Series in Informatics (OASIcs), Volume 8, pp. 1-8, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2008)
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@InProceedings{altmeyer_et_al:OASIcs.WCET.2008.1664,
author = {Altmeyer, Sebastian and Gebhard, Gernot},
title = {{WCET Analysis for Preemptive Scheduling}},
booktitle = {8th International Workshop on Worst-Case Execution Time Analysis (WCET'08)},
pages = {1--8},
series = {Open Access Series in Informatics (OASIcs)},
ISBN = {978-3-939897-10-1},
ISSN = {2190-6807},
year = {2008},
volume = {8},
editor = {Kirner, Raimund},
publisher = {Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
address = {Dagstuhl, Germany},
URL = {https://drops-dev.dagstuhl.de/entities/document/10.4230/OASIcs.WCET.2008.1664},
URN = {urn:nbn:de:0030-drops-16644},
doi = {10.4230/OASIcs.WCET.2008.1664},
annote = {Keywords: WCET, Preemption}
}