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Documents authored by Ruiz, Jordy


Document
The W-SEPT Project: Towards Semantic-Aware WCET Estimation

Authors: Claire Maiza, Pascal Raymond, Catherine Parent-Vigouroux, Armelle Bonenfant, Fabienne Carrier, Hugues Cassé, Philippe Cuenot, Denis Claraz, Nicolas Halbwachs, Erwan Jahier, Hanbing Li, Marianne de Michiel, Vincent Mussot, Isabelle Puaut, Christine Rochange, Erven Rohou, Jordy Ruiz, Pascal Sotin, and Wei-Tsun Sun

Published in: OASIcs, Volume 57, 17th International Workshop on Worst-Case Execution Time Analysis (WCET 2017)


Abstract
Critical embedded systems are generally composed of repetitive tasks that must meet hard timing constraints, such as termination deadlines. Providing an upper bound of the worst-case execution time (WCET) of such tasks at design time is necessary to guarantee the correctness of the system. In static WCET analysis, a main source of over-approximation comes from the complexity of the modern hardware platforms: their timing behavior tends to become more unpredictable because of features like caches, pipeline, branch prediction, etc. Another source of over-approximation comes from the software itself: WCET analysis may consider potential worst-cases executions that are actually infeasible, because of the semantics of the program or because they correspond to unrealistic inputs. The W-SEPT project, for "WCET, Semantics, Precision and Traceability", has been carried out to study and exploit the influence of program semantics on the WCET estimation. This paper presents the results of this project : a semantic-aware WCET estimation workflow for high-level designed systems.

Cite as

Claire Maiza, Pascal Raymond, Catherine Parent-Vigouroux, Armelle Bonenfant, Fabienne Carrier, Hugues Cassé, Philippe Cuenot, Denis Claraz, Nicolas Halbwachs, Erwan Jahier, Hanbing Li, Marianne de Michiel, Vincent Mussot, Isabelle Puaut, Christine Rochange, Erven Rohou, Jordy Ruiz, Pascal Sotin, and Wei-Tsun Sun. The W-SEPT Project: Towards Semantic-Aware WCET Estimation. In 17th International Workshop on Worst-Case Execution Time Analysis (WCET 2017). Open Access Series in Informatics (OASIcs), Volume 57, pp. 9:1-9:13, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2017)


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@InProceedings{maiza_et_al:OASIcs.WCET.2017.9,
  author =	{Maiza, Claire and Raymond, Pascal and Parent-Vigouroux, Catherine and Bonenfant, Armelle and Carrier, Fabienne and Cass\'{e}, Hugues and Cuenot, Philippe and Claraz, Denis and Halbwachs, Nicolas and Jahier, Erwan and Li, Hanbing and de Michiel, Marianne and Mussot, Vincent and Puaut, Isabelle and Rochange, Christine and Rohou, Erven and Ruiz, Jordy and Sotin, Pascal and Sun, Wei-Tsun},
  title =	{{The W-SEPT Project: Towards Semantic-Aware WCET Estimation}},
  booktitle =	{17th International Workshop on Worst-Case Execution Time Analysis (WCET 2017)},
  pages =	{9:1--9:13},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-95977-057-6},
  ISSN =	{2190-6807},
  year =	{2017},
  volume =	{57},
  editor =	{Reineke, Jan},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.WCET.2017.9},
  URN =		{urn:nbn:de:0030-drops-73097},
  doi =		{10.4230/OASIcs.WCET.2017.9},
  annote =	{Keywords: Worst-case execution time analysis, Static analysis, Program analysis}
}
Document
Expressing and Exploiting Conflicts over Paths in WCET Analysis

Authors: Vincent Mussot, Jordy Ruiz, Pascal Sotin, Marianne de Michiel, and Hugues Cassé

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


Abstract
The presence of infeasible paths in a program is a source of imprecision in the Worst-Case Execution Time (WCET) analysis. Detecting, expressing and exploiting such paths can improve the WCET estimation or, at least, improve the confidence we have in estimation precision. In this article, we propose an extension of the FFX format to express conflicts over paths and we detail two ways of enhancing the WCET analyses with that information. We demonstrate and compare these techniques on the Mälardalen benchmark suite and on C code generated from Esterel.

Cite as

Vincent Mussot, Jordy Ruiz, Pascal Sotin, Marianne de Michiel, and Hugues Cassé. Expressing and Exploiting Conflicts over Paths in WCET Analysis. In 16th International Workshop on Worst-Case Execution Time Analysis (WCET 2016). Open Access Series in Informatics (OASIcs), Volume 55, pp. 3:1-3:11, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2016)


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@InProceedings{mussot_et_al:OASIcs.WCET.2016.3,
  author =	{Mussot, Vincent and Ruiz, Jordy and Sotin, Pascal and de Michiel, Marianne and Cass\'{e}, Hugues},
  title =	{{Expressing and Exploiting Conflicts over Paths in WCET Analysis}},
  booktitle =	{16th International Workshop on Worst-Case Execution Time Analysis (WCET 2016)},
  pages =	{3:1--3:11},
  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.2016.3},
  URN =		{urn:nbn:de:0030-drops-68966},
  doi =		{10.4230/OASIcs.WCET.2016.3},
  annote =	{Keywords: WCET analysis, Infeasible paths, Path conflicts, IPET, CFG transformation}
}
Document
Using SMT Solving for the Lookup of Infeasible Paths in Binary Programs

Authors: Jordy Ruiz and Hugues Cassé

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


Abstract
Worst-Case Execution Time (WCET) is a key component to check temporal constraints of realtime systems. WCET by static analysis provides a safe upper bound. While hardware modelling is now efficient, loss of precision stems mainly in the inclusion of infeasible execution paths in the WCET calculation. This paper proposes a new method to detect such paths based on static analysis of machine code and the feasibility test of conditions using Satisfiability Modulo Theory (SMT) solvers. The experimentation shows promising results although the expected precision was slightly lowered due to clamping operations needed to cope with complexity explosion. An important point is that the implementation has been performed in the OTAWA framework and is independent of any instruction set thanks to its semantic instructions.

Cite as

Jordy Ruiz and Hugues Cassé. Using SMT Solving for the Lookup of Infeasible Paths in Binary Programs. In 15th International Workshop on Worst-Case Execution Time Analysis (WCET 2015). Open Access Series in Informatics (OASIcs), Volume 47, pp. 95-104, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2015)


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@InProceedings{ruiz_et_al:OASIcs.WCET.2015.95,
  author =	{Ruiz, Jordy and Cass\'{e}, Hugues},
  title =	{{Using SMT Solving for the Lookup of Infeasible Paths in Binary Programs}},
  booktitle =	{15th International Workshop on Worst-Case Execution Time Analysis (WCET 2015)},
  pages =	{95--104},
  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.2015.95},
  URN =		{urn:nbn:de:0030-drops-52604},
  doi =		{10.4230/OASIcs.WCET.2015.95},
  annote =	{Keywords: WCET, infeasible paths, SMT, machine code}
}
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