Search Results

Documents authored by Lisper, Björn

Document
DOI: 10.4230/OASIcs.WCET.2016.2
TACLeBench: A Benchmark Collection to Support Worst-Case Execution Time Research

Authors: Heiko Falk, Sebastian Altmeyer, Peter Hellinckx, Björn Lisper, Wolfgang Puffitsch, Christine Rochange, Martin Schoeberl, Rasmus Bo Sørensen, Peter Wägemann, and Simon Wegener

Published in: OASIcs, Volume 55, 16th International Workshop on Worst-Case Execution Time Analysis (WCET 2016)

Abstract
Engineering related research, such as research on worst-case execution time, uses experimentation to evaluate ideas. For these experiments we need example programs. Furthermore, to make the research experimentation repeatable those programs shall be made publicly available. We collected open-source programs, adapted them to a common coding style, and provide the collection in open-source. The benchmark collection is called TACLeBench and is available from GitHub in version 1.9 at the publication date of this paper. One of the main features of TACLeBench is that all programs are self-contained without any dependencies on standard libraries or an operating system.
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Heiko Falk, Sebastian Altmeyer, Peter Hellinckx, Björn Lisper, Wolfgang Puffitsch, Christine Rochange, Martin Schoeberl, Rasmus Bo Sørensen, Peter Wägemann, and Simon Wegener. TACLeBench: A Benchmark Collection to Support Worst-Case Execution Time Research. In 16th International Workshop on Worst-Case Execution Time Analysis (WCET 2016). Open Access Series in Informatics (OASIcs), Volume 55, pp. 2:1-2:10, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2016)

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@InProceedings{falk_et_al:OASIcs.WCET.2016.2,
  author =	{Falk, Heiko and Altmeyer, Sebastian and Hellinckx, Peter and Lisper, Bj\"{o}rn and Puffitsch, Wolfgang and Rochange, Christine and Schoeberl, Martin and S{\o}rensen, Rasmus Bo and W\"{a}gemann, Peter and Wegener, Simon},
  title =	{{TACLeBench: A Benchmark Collection to Support Worst-Case Execution Time Research}},
  booktitle =	{16th International Workshop on Worst-Case Execution Time Analysis (WCET 2016)},
  pages =	{2:1--2:10},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-95977-025-5},
  ISSN =	{2190-6807},
  year =	{2016},
  volume =	{55},
  editor =	{Schoeberl, Martin},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.WCET.2016.2},
  URN =		{urn:nbn:de:0030-drops-68958},
  doi =		{10.4230/OASIcs.WCET.2016.2},
  annote =	{Keywords: Benchmark, WCET analysis, real-time systems}
}
Document
DOI: 10.4230/OASIcs.WCET.2015.65
WCET and Mixed-Criticality: What does Confidence in WCET Estimations Depend Upon?

Authors: Sebastian Altmeyer, Björn Lisper, Claire Maiza, Jan Reineke, and Christine Rochange

Published in: OASIcs, Volume 47, 15th International Workshop on Worst-Case Execution Time Analysis (WCET 2015)

Abstract
Mixed-criticality systems integrate components of different criticality. Different criticality levels require different levels of confidence in the correct behavior of a component. One aspect of correctness is timing. Confidence in worst-case execution time (WCET) estimates depends on the process by which they have been obtained. A somewhat naive view is that static WCET analyses determines safe bounds in which we can have absolute confidence, while measurement-based approaches are inherently unreliable. In this paper, we refine this view by exploring sources of doubt in the correctness of both static and measurement-based WCET analysis.
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Sebastian Altmeyer, Björn Lisper, Claire Maiza, Jan Reineke, and Christine Rochange. WCET and Mixed-Criticality: What does Confidence in WCET Estimations Depend Upon?. In 15th International Workshop on Worst-Case Execution Time Analysis (WCET 2015). Open Access Series in Informatics (OASIcs), Volume 47, pp. 65-74, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2015)

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@InProceedings{altmeyer_et_al:OASIcs.WCET.2015.65,
  author =	{Altmeyer, Sebastian and Lisper, Bj\"{o}rn and Maiza, Claire and Reineke, Jan and Rochange, Christine},
  title =	{{WCET and Mixed-Criticality: What does Confidence in WCET Estimations Depend Upon?}},
  booktitle =	{15th International Workshop on Worst-Case Execution Time Analysis (WCET 2015)},
  pages =	{65--74},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-939897-95-8},
  ISSN =	{2190-6807},
  year =	{2015},
  volume =	{47},
  editor =	{Cazorla, Francisco J.},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.WCET.2015.65},
  URN =		{urn:nbn:de:0030-drops-52574},
  doi =		{10.4230/OASIcs.WCET.2015.65},
  annote =	{Keywords: mixed criticality, WCET analysis, confidence in WCET estimates}
}
Document
DOI: 10.4230/OASIcs.WCET.2015.85
Analysing Switch-Case Code with Abstract Execution

Authors: Niklas Holsti, Jan Gustafsson, Linus Källberg, and Björn Lisper

Published in: OASIcs, Volume 47, 15th International Workshop on Worst-Case Execution Time Analysis (WCET 2015)

Abstract
Constructing the control-flow graph (CFG) of machine code is made difficult by dynamic transfers of control (DTC), where the address of the next instruction is computed at run-time. Switchcase statements make compilers generate a large variety of machine-code forms with DTC. Two analysis approaches are commonly used: pattern-matching methods identify predefined instruction patterns to extract the target addresses, while analytical methods try to compute the set of target addresses using a general value-analysis. We tested the abstract execution method of the SWEET tool as a value analysis for switch-case code. SWEET is here used as a plugin to the Bound-T tool: thus our work can also be seen as an experiment in modular tool design, where a general value-analysis tool is used to aid the CFG construction in a WCET analysis tool. We find that the abstract-execution analysis works at least as well as the switch-case analyses in Bound-T itself, which are mostly based on pattern-matching. However, there are still some weaknesses: the abstract domains available in SWEET are not well suited to representing sets of DTC target addresses, which are small but sparse and irregular. Also, in some cases the abstract-execution analysis fails because the used domain is not relational, that is, does not model arithmetic relationships between the values of different variables. Future work will be directed towards the design of abstract domains eliminating these weaknesses.
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Niklas Holsti, Jan Gustafsson, Linus Källberg, and Björn Lisper. Analysing Switch-Case Code with Abstract Execution. In 15th International Workshop on Worst-Case Execution Time Analysis (WCET 2015). Open Access Series in Informatics (OASIcs), Volume 47, pp. 85-94, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2015)

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@InProceedings{holsti_et_al:OASIcs.WCET.2015.85,
  author =	{Holsti, Niklas and Gustafsson, Jan and K\"{a}llberg, Linus and Lisper, Bj\"{o}rn},
  title =	{{Analysing Switch-Case Code with Abstract Execution}},
  booktitle =	{15th International Workshop on Worst-Case Execution Time Analysis (WCET 2015)},
  pages =	{85--94},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-939897-95-8},
  ISSN =	{2190-6807},
  year =	{2015},
  volume =	{47},
  editor =	{Cazorla, Francisco J.},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.WCET.2015.85},
  URN =		{urn:nbn:de:0030-drops-52598},
  doi =		{10.4230/OASIcs.WCET.2015.85},
  annote =	{Keywords: ynamic control flow, indexed branch, machine-code analysis, WCET analysis}
}
Document
DOI: 10.4230/OASIcs.WCET.2014.1
Principles for Value Annotation Languages

Authors: Björn Lisper

Published in: OASIcs, Volume 39, 14th International Workshop on Worst-Case Execution Time Analysis (2014)

Abstract
Tools for code-level program analysis need formats to express various properties, like relevant properties of the environment where the analysed code will execute, and the analysis results. Different WCET analysis tools typically use tool-specific annotation languages for this purpose. These languages are often geared towards expressing properties that the particular tool can handle rather than being general, and mostly their semantics is only specified informally. This makes it harder for tools to communicate, as well as for users to provide relevant information to them. Here, we propose a small but general assertion language for value constraints including IPET flow facts, which is an important class of annotations for WCET analysis tools. We show how to express interesting properties in this language, we propose some syntactic conveniences, and we give the language a formal semantics. The language could be used directly as a tool-independent annotation language, or as a meta-language to give exact semantics to existing value annotation and flow fact formats.
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Björn Lisper. Principles for Value Annotation Languages. In 14th International Workshop on Worst-Case Execution Time Analysis. Open Access Series in Informatics (OASIcs), Volume 39, pp. 1-10, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2014)

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@InProceedings{lisper:OASIcs.WCET.2014.1,
  author =	{Lisper, Bj\"{o}rn},
  title =	{{Principles for Value Annotation Languages}},
  booktitle =	{14th International Workshop on Worst-Case Execution Time Analysis},
  pages =	{1--10},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-939897-69-9},
  ISSN =	{2190-6807},
  year =	{2014},
  volume =	{39},
  editor =	{Falk, Heiko},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.WCET.2014.1},
  URN =		{urn:nbn:de:0030-drops-45996},
  doi =		{10.4230/OASIcs.WCET.2014.1},
  annote =	{Keywords: Real-Time System, WCET analysis, Flow Fact, Assertion}
}
Document
Complete Volume
DOI: 10.4230/OASIcs.WCET.2010
OASIcs, Volume 15, WCET'10, Complete Volume

Authors: Björn Lisper

Published in: OASIcs, Volume 15, 10th International Workshop on Worst-Case Execution Time Analysis (WCET 2010)

Abstract
OASIcs, Volume 15, WCET'10, Complete Volume
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10th International Workshop on Worst-Case Execution Time Analysis (WCET 2010). Open Access Series in Informatics (OASIcs), Volume 15, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2012)

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@Proceedings{lisper:OASIcs.WCET.2010,
  title =	{{OASIcs, Volume 15, WCET'10, Complete Volume}},
  booktitle =	{10th International Workshop on Worst-Case Execution Time Analysis (WCET 2010)},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-939897-21-7},
  ISSN =	{2190-6807},
  year =	{2012},
  volume =	{15},
  editor =	{Lisper, Bj\"{o}rn},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.WCET.2010},
  URN =		{urn:nbn:de:0030-drops-35771},
  doi =		{10.4230/OASIcs.WCET.2010},
  annote =	{Keywords: Performance of Systems, Software/Program Verification, Computers in Other Systems}
}
Document
DOI: 10.4230/OASIcs.WCET.2012.38
Toward Static Timing Analysis of Parallel Software

Authors: Andreas Gustavsson, Jan Gustafsson, and Björn Lisper

Published in: OASIcs, Volume 23, 12th International Workshop on Worst-Case Execution Time Analysis (2012)

Abstract
The current trend within computer, and even real-time, systems is to incorporate parallel hardware, e.g., multicore processors, and parallel software. Thus, the ability to safely analyse such parallel systems, e.g., regarding the timing behaviour, becomes necessary. Static timing analysis is an approach to mathematically derive safe bounds on the execution time of a program, when executed on a given hardware platform. This paper presents an algorithm that statically analyses the timing of parallel software, with threads communicating through shared memory, using abstract interpretation. It also gives an extensive example to clarify how the algorithm works.
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Andreas Gustavsson, Jan Gustafsson, and Björn Lisper. Toward Static Timing Analysis of Parallel Software. In 12th International Workshop on Worst-Case Execution Time Analysis. Open Access Series in Informatics (OASIcs), Volume 23, pp. 38-47, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2012)

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@InProceedings{gustavsson_et_al:OASIcs.WCET.2012.38,
  author =	{Gustavsson, Andreas and Gustafsson, Jan and Lisper, Bj\"{o}rn},
  title =	{{Toward Static Timing Analysis of Parallel Software}},
  booktitle =	{12th International Workshop on Worst-Case Execution Time Analysis},
  pages =	{38--47},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-939897-41-5},
  ISSN =	{2190-6807},
  year =	{2012},
  volume =	{23},
  editor =	{Vardanega, Tullio},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.WCET.2012.38},
  URN =		{urn:nbn:de:0030-drops-35552},
  doi =		{10.4230/OASIcs.WCET.2012.38},
  annote =	{Keywords: Parallelism, BCET, WCET, Static analysis, Abstract interpretation}
}
Document
DOI: 10.4230/OASIcs.WCET.2012.48
Towards Parallel Programming Models for Predictability

Authors: Björn Lisper

Published in: OASIcs, Volume 23, 12th International Workshop on Worst-Case Execution Time Analysis (2012)

Abstract
Future embedded systems for performance-demanding applications will be massively parallel. High performance tasks will be parallel programs, running on several cores, rather than single threads running on single cores. For hard real-time applications, WCETs for such tasks must be bounded. Low-level parallel programming models, based on concurrent threads, are notoriously hard to use due to their inherent nondeterminism. Therefore the parallel processing community has long considered high-level parallel programming models, which restrict the low-level models to regain determinism. In this position paper we argue that such parallel programming models are beneficial also for WCET analysis of parallel programs. We review some proposed models, and discuss their influence on timing predictability. In particular we identify data parallel programming as a suitable paradigm as it is deterministic and allows current methods for WCET analysis to be extended to parallel code. GPUs are increasingly used for high performance applications: we discuss a current GPU architecture, and we argue that it offers a parallel platform for compute-intensive applications for which it seems possible to construct precise timing models. Thus, a promising route for the future is to develop WCET analyses for data-parallel software running on GPUs.
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Björn Lisper. Towards Parallel Programming Models for Predictability. In 12th International Workshop on Worst-Case Execution Time Analysis. Open Access Series in Informatics (OASIcs), Volume 23, pp. 48-58, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2012)

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@InProceedings{lisper:OASIcs.WCET.2012.48,
  author =	{Lisper, Bj\"{o}rn},
  title =	{{Towards Parallel Programming Models for Predictability}},
  booktitle =	{12th International Workshop on Worst-Case Execution Time Analysis},
  pages =	{48--58},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-939897-41-5},
  ISSN =	{2190-6807},
  year =	{2012},
  volume =	{23},
  editor =	{Vardanega, Tullio},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.WCET.2012.48},
  URN =		{urn:nbn:de:0030-drops-35565},
  doi =		{10.4230/OASIcs.WCET.2012.48},
  annote =	{Keywords: Real-Time System, WCET analysis, Parallel Program, Data Parallelism}
}
Document
Front Matter
DOI: 10.4230/OASIcs.WCET.2010.i
Frontmatter, Preface, Table of Contents, Workshop Organization

Authors: Björn Lisper

Published in: OASIcs, Volume 15, 10th International Workshop on Worst-Case Execution Time Analysis (WCET 2010)

Abstract
Frontmatter, Preface, Table of Contents, Workshop Organization.
Cite as

10th International Workshop on Worst-Case Execution Time Analysis (WCET 2010). Open Access Series in Informatics (OASIcs), Volume 15, pp. i-ix, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2010)

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@InProceedings{lisper:OASIcs.WCET.2010.i,
  author =	{Lisper, Bj\"{o}rn},
  title =	{{Frontmatter, Preface, Table of Contents, Workshop Organization}},
  booktitle =	{10th International Workshop on Worst-Case Execution Time Analysis (WCET 2010)},
  pages =	{i--ix},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-939897-21-7},
  ISSN =	{2190-6807},
  year =	{2010},
  volume =	{15},
  editor =	{Lisper, Bj\"{o}rn},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.WCET.2010.i},
  URN =		{urn:nbn:de:0030-drops-28195},
  doi =		{10.4230/OASIcs.WCET.2010.i},
  annote =	{Keywords: Frontmatter, Preface, Table of Contents, Workshop Organization}
}
Document
DOI: 10.4230/OASIcs.WCET.2010.101
Towards WCET Analysis of Multicore Architectures Using UPPAAL

Authors: Andreas Gustavsson, Andreas Ermedahl, Björn Lisper, and Paul Pettersson

Published in: OASIcs, Volume 15, 10th International Workshop on Worst-Case Execution Time Analysis (WCET 2010)

Abstract
To take full advantage of the increasingly used shared-memory multicore architectures, software algorithms will need to be parallelized over multiple threads. This means that threads will have to share resources (e.g. some level of cache) and communicate and synchronize with each other. There already exist software libraries (e.g. OpenMP) used to explicitly parallelize available sequential C/C++ and Fortran code, which means that parallel code could be easily obtained. To be able to use parallel software running on multicore architectures in embedded systems with hard real-time constraints, new WCET (Worst-Case Execution Time) analysis methods and tools must be developed. This paper investigates a method based on model-checking a system of timed automata using the UPPAAL tool box. It is found that it is possible to perform WCET analysis on (small) parallel systems using UPPAAL. We also show how to model thread synchronization using spinlock-like primitives.
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Andreas Gustavsson, Andreas Ermedahl, Björn Lisper, and Paul Pettersson. Towards WCET Analysis of Multicore Architectures Using UPPAAL. In 10th International Workshop on Worst-Case Execution Time Analysis (WCET 2010). Open Access Series in Informatics (OASIcs), Volume 15, pp. 101-112, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2010)

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@InProceedings{gustavsson_et_al:OASIcs.WCET.2010.101,
  author =	{Gustavsson, Andreas and Ermedahl, Andreas and Lisper, Bj\"{o}rn and Pettersson, Paul},
  title =	{{Towards WCET Analysis of Multicore Architectures Using UPPAAL}},
  booktitle =	{10th International Workshop on Worst-Case Execution Time Analysis (WCET 2010)},
  pages =	{101--112},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-939897-21-7},
  ISSN =	{2190-6807},
  year =	{2010},
  volume =	{15},
  editor =	{Lisper, Bj\"{o}rn},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.WCET.2010.101},
  URN =		{urn:nbn:de:0030-drops-28304},
  doi =		{10.4230/OASIcs.WCET.2010.101},
  annote =	{Keywords: WCET, Multicore, Parallel, Thread Synchronization, Model-Checking, UPPAAL}
}
Document
DOI: 10.4230/OASIcs.WCET.2010.136
The Mälardalen WCET Benchmarks: Past, Present And Future

Authors: Jan Gustafsson, Adam Betts, Andreas Ermedahl, and Björn Lisper

Published in: OASIcs, Volume 15, 10th International Workshop on Worst-Case Execution Time Analysis (WCET 2010)

Abstract
Modelling of real-time systems requires accurate and tight estimates of the Worst-Case Execution Time (WCET) of each task scheduled to run. In the past two decades, two main paradigms have emerged within the field of WCET analysis: static analysis and hybrid measurement-based analysis. These techniques have been succesfully implemented in prototype and commercial toolsets. Yet, comparison among the WCET estimates derived by such tools remains somewhat elusive as it requires a common set of benchmarks which serve a multitude of needs. The Maelardalen WCET research group maintains a large number of WCET benchmark programs for this purpose. This paper describes properties of the existing benchmarks, including their relative strengths and weaknesses. We propose extensions to the benchmarks which will allow any type of WCET tool evaluate its results against other state-of-the-art tools, thus setting a high standard for future research and development. We also propose an organization supporting the future work with the benchmarks. We suggest to form a committee with a responsibility for the benchmarks, and that the benchmark web site is transformed to an open wiki, with possibility for the WCET community to easily update the benchmarks.
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Jan Gustafsson, Adam Betts, Andreas Ermedahl, and Björn Lisper. The Mälardalen WCET Benchmarks: Past, Present And Future. In 10th International Workshop on Worst-Case Execution Time Analysis (WCET 2010). Open Access Series in Informatics (OASIcs), Volume 15, pp. 136-146, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2010)

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@InProceedings{gustafsson_et_al:OASIcs.WCET.2010.136,
  author =	{Gustafsson, Jan and Betts, Adam and Ermedahl, Andreas and Lisper, Bj\"{o}rn},
  title =	{{The M\"{a}lardalen WCET Benchmarks: Past, Present And Future}},
  booktitle =	{10th International Workshop on Worst-Case Execution Time Analysis (WCET 2010)},
  pages =	{136--146},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-939897-21-7},
  ISSN =	{2190-6807},
  year =	{2010},
  volume =	{15},
  editor =	{Lisper, Bj\"{o}rn},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.WCET.2010.136},
  URN =		{urn:nbn:de:0030-drops-28336},
  doi =		{10.4230/OASIcs.WCET.2010.136},
  annote =	{Keywords: WCET analysis, benchmark}
}
Document
DOI: 10.4230/OASIcs.WCET.2009.2279
ALF - A Language for WCET Flow Analysis

Authors: Jan Gustafsson, Andreas Ermedahl, Björn Lisper, Christer Sandberg, and Linus Källberg

Published in: OASIcs, Volume 10, 9th International Workshop on Worst-Case Execution Time Analysis (WCET'09) (2009)

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 the flow analysis, which derives bounds on the number of times different code entities can be executed. Examples of flow information derived by a flow analysis are loop bounds and infeasible paths. Flow analysis can be performed on source code, intermediate code, or binary code: for the latter, there is a proliferation of instruction sets. Thus, flow analysis must deal with many code formats. However, the basic flow analysis techniques are more or less the same regardless of the code format. Thus, an interesting option is to define a common code format for flow analysis, which also allows for easy translation from the other formats. Flow analyses for this common format will then be portable, in principle supporting all types of code formats which can be translated to this format. Further, a common format simplifies the development of flow analyses, since only one specific code format needs to be targeted. This paper presents such a common code format, the ALF language (ARTIST2 Language for WCET Flow Analysis).
Cite as

Jan Gustafsson, Andreas Ermedahl, Björn Lisper, Christer Sandberg, and Linus Källberg. ALF - A Language for WCET Flow Analysis. In 9th International Workshop on Worst-Case Execution Time Analysis (WCET'09). Open Access Series in Informatics (OASIcs), Volume 10, pp. 1-11, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2009)

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@InProceedings{gustafsson_et_al:OASIcs.WCET.2009.2279,
  author =	{Gustafsson, Jan and Ermedahl, Andreas and Lisper, Bj\"{o}rn and Sandberg, Christer and K\"{a}llberg, Linus},
  title =	{{ALF - A Language for WCET Flow Analysis}},
  booktitle =	{9th International Workshop on Worst-Case Execution Time Analysis (WCET'09)},
  pages =	{1--11},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-939897-14-9},
  ISSN =	{2190-6807},
  year =	{2009},
  volume =	{10},
  editor =	{Holsti, Niklas},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.WCET.2009.2279},
  URN =		{urn:nbn:de:0030-drops-22791},
  doi =		{10.4230/OASIcs.WCET.2009.2279},
  annote =	{Keywords: WCET analysis, flow analysis, ALF WCET analysis, flow analysis, ALF}
}
Document
DOI: 10.4230/OASIcs.WCET.2008.1659
Towards an Automatic Parametric WCET Analysis

Authors: Stefan Bygde and Björn Lisper

Published in: OASIcs, Volume 8, 8th International Workshop on Worst-Case Execution Time Analysis (WCET'08) (2008)

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.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
DOI: 10.4230/OASIcs.WCET.2007.1194
Loop Bound Analysis based on a Combination of Program Slicing, Abstract Interpretation, and Invariant Analysis

Authors: Andreas Ermedahl, Christer Sandberg, Jan Gustafsson, Stefan Bygde, and Björn Lisper

Published in: OASIcs, Volume 6, 7th International Workshop on Worst-Case Execution Time Analysis (WCET'07) (2007)

Abstract
Static Worst-Case Execution Time (WCET) analysis is a technique to derive upper bounds for the execution times of programs. Such bounds are crucial when designing and verifying real-time systems. A key component for static derivation of precise WCET estimates is upper bounds on the number of times different loops can be iterated. In this paper we present an approach for deriving upper loop bounds based on a combination of standard program analysis techniques. The idea is to bound the number of different states in the loop which can influence the exit conditions. Given that the loop terminates, this number provides an upper loop bound. An algorithm based on the approach has been implemented in our WCET analysis tool SWEET. We evaluate the algorithm on a number of standard WCET benchmarks, giving evidence that it is capable to derive valid bounds for many types of loops.
Cite as

Andreas Ermedahl, Christer Sandberg, Jan Gustafsson, Stefan Bygde, and Björn Lisper. Loop Bound Analysis based on a Combination of Program Slicing, Abstract Interpretation, and Invariant Analysis. In 7th International Workshop on Worst-Case Execution Time Analysis (WCET'07). Open Access Series in Informatics (OASIcs), Volume 6, pp. 1-6, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2007)

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@InProceedings{ermedahl_et_al:OASIcs.WCET.2007.1194,
  author =	{Ermedahl, Andreas and Sandberg, Christer and Gustafsson, Jan and Bygde, Stefan and Lisper, Bj\"{o}rn},
  title =	{{Loop Bound Analysis based on a Combination of Program Slicing, Abstract Interpretation, and Invariant Analysis}},
  booktitle =	{7th International Workshop on Worst-Case Execution Time Analysis (WCET'07)},
  pages =	{1--6},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-939897-05-7},
  ISSN =	{2190-6807},
  year =	{2007},
  volume =	{6},
  editor =	{Rochange, Christine},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.WCET.2007.1194},
  URN =		{urn:nbn:de:0030-drops-11946},
  doi =		{10.4230/OASIcs.WCET.2007.1194},
  annote =	{Keywords: WCET analysis, loop-bound analysis, program slicing, abstract interpretation, invariant analysis}
}
Document
DOI: 10.4230/OASIcs.WCET.2005.811
Experiences from Industrial WCET Analysis Case Studies

Authors: Andreas Ermedahl, Jan Gustafsson, and Björn Lisper

Published in: OASIcs, Volume 1, 5th International Workshop on Worst-Case Execution Time Analysis (WCET'05) (2007)

Abstract
Static Worst-Case Execution Time (WCET) analysis is currently taking a step from research to industrial use. We present a summary of three case studies where static WCET analysis has been used to analyse production code for embedded real-time systems. The primary purpose has not been to test the accuracy of the obtained WCET estimates, but rather to investigate the practical and methodological difficulties that arise when applying current WCET analysis methods to these particular kind of systems. In particular, we have been interested in how laborintensive the analysis becomes, for instance by estimating the efforts to study the analysed code in detail, and measuring the number of manual annotations necessary to perform the analysis. From these observations, we draw some conclusions about what would be needed to turn static WCET analysis into a useful tool for embedded and real-time systems software development.
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Andreas Ermedahl, Jan Gustafsson, and Björn Lisper. Experiences from Industrial WCET Analysis Case Studies. In 5th International Workshop on Worst-Case Execution Time Analysis (WCET'05). Open Access Series in Informatics (OASIcs), Volume 1, pp. 25-28, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2007)

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@InProceedings{ermedahl_et_al:OASIcs.WCET.2005.811,
  author =	{Ermedahl, Andreas and Gustafsson, Jan and Lisper, Bj\"{o}rn},
  title =	{{Experiences from Industrial WCET Analysis Case Studies}},
  booktitle =	{5th International Workshop on Worst-Case Execution Time Analysis (WCET'05)},
  pages =	{25--28},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-939897-24-8},
  ISSN =	{2190-6807},
  year =	{2007},
  volume =	{1},
  editor =	{Wilhelm, Reinhard},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.WCET.2005.811},
  URN =		{urn:nbn:de:0030-drops-8118},
  doi =		{10.4230/OASIcs.WCET.2005.811},
  annote =	{Keywords: }
}
Document
DOI: 10.4230/OASIcs.WCET.2006.667
Algorithms for Infeasible Path Calculation

Authors: Jan Gustaffson, Andreas Ermedahl, and Björn Lisper

Published in: OASIcs, Volume 4, 6th International Workshop on Worst-Case Execution Time Analysis (WCET'06) (2006)

Abstract
Static Worst-Case Execution Time (WCET) analysis is a technique to derive upper bounds for the execution times of programs. Such bounds are crucial when designing and verifying real-time systems. One key component in static WCET analysis is to derive flow information, such as loop bounds and infeasible paths for the analysed program. Such flow information can be provided as either as annotations by the user, can be automatically calculated by a flow analysis, or by a combination of both. To make the analysis as simple, automatic and safe as possible, this flow information should be calculated automatically with no or very limited user interaction. In this paper we present three novel algorithms to calculate infeasible paths. The algorithms are all designed to be simple and efficient, both in terms of generated flow facts and in analysis running time. The algorithms have been implemented and tested for a set of WCET benchmarks programs.
Cite as

Jan Gustaffson, Andreas Ermedahl, and Björn Lisper. Algorithms for Infeasible Path Calculation. In 6th International Workshop on Worst-Case Execution Time Analysis (WCET'06). Open Access Series in Informatics (OASIcs), Volume 4, pp. 1-6, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2006)

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@InProceedings{gustaffson_et_al:OASIcs.WCET.2006.667,
  author =	{Gustaffson, Jan and Ermedahl, Andreas and Lisper, Bj\"{o}rn},
  title =	{{Algorithms for Infeasible Path Calculation}},
  booktitle =	{6th International Workshop on Worst-Case Execution Time Analysis (WCET'06)},
  pages =	{1--6},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-939897-03-3},
  ISSN =	{2190-6807},
  year =	{2006},
  volume =	{4},
  editor =	{Mueller, Frank},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.WCET.2006.667},
  URN =		{urn:nbn:de:0030-drops-6677},
  doi =		{10.4230/OASIcs.WCET.2006.667},
  annote =	{Keywords: Worst case execution time, real-time, control flow analysis, abstract interpretation, infeasible paths}
}
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