Warp-Level CFG Construction for GPU Kernel WCET Analysis

International audienceWe present an abstract interpretation technique to automatically build a Control Flow Graph (CFG) representation of the execution of a GPU kernel. GPUs implement an inherently parallel execution model, in which threads are grouped within so-called warps that execute in lockstep. This execution model enables the representation of the execution of the threads of a warp as a single CFG. However, thread divergence may appear within a warp and its effect must be captured explicitly within the CFG. Our method builds the CFG of a warp by applying abstract interpretation on the assembly (Nvidia SASS) code of a kernel, and by maintaining an abstract representation of which threads within the warp agree on which values. This allows the method to detect precisely the points in the program where thread divergence may occur, and avoid spurious reactivation edges in the CFG. We apply our technique on benchmark kernels as a proof-of-concept, and generate IPET systems using the resulting CFGs

Variations morphologiques et réponses démographiques de l'Emyde lépreuse Mauremys leprosa à des habitats aquatiques hétérogènes

International audienceHuman activities affect terrestrial and aquatic habitats leading to changes at both individual and population levels in wild animal species. In this study, we investigated the phenotype and demographics of the Mediterranean pond turtle Mauremys leprosa (Schweigger, 1812) in contrasted environments of Southern France: two peri-urban rivers receiving effluents from wastewater treatment plants (WWTP), and another one without sewage treatment plant. Our findings revealed the presence of pesticides and pharmaceuticals in the three rivers of investigation, the highest diversities and concentrations of pollutants being found in the river subsections impacted by WWTP effluents. Principal component analysis and hierarchical clustering identified three levels of habitat quality, with different pollutant concentrations, thermal conditions, nutrient, and organic matter levels. The highest turtle densities, growth rates, and body sizes were estimated in the most disturbed habitats, suggesting potential adult benefits derived from harsh environmental conditions induced by pollution and eutrophication. Conversely, juveniles were the most abundant in the least polluted habitats, suggesting adverse effects of pollution on juvenile survival or adult reproduction. This study suggests that turtles living in polluted habitats may benefit from enhanced growth and body size, at the expense of reproductive success

(Table 2) Age determination of sediment core IG-KS-11 the Demerara Plateau, North Atlantic

The Demerara Plateau, belonging to the passive transform margin of French Guiana, was investigated during the IGUANES cruise in 2013. The objectives of the cruise were to explore the poorly-known surficial sedimentary column overlying thick mass transport deposits as well as to understand the factors controlling recent sedimentation. The presence of numerous bedforms at the seafloor was observed thanks to newly acquired IGUANES bathymetric, high resolution seismic and chirp data, while sediment cores allowed the characterization of the deposits covering the mass transport deposits. Modern oceanographic conditions were determined in situ, using mooring monitoring over a 10-month period. Our data indicate the presence of a Contourite Depositional System along the Demerara Plateau, most likely related to bottom current activity of the North Atlantic Deep Water (NADW). However, at the regional scale, large longitudinal waves parallel the NADW flow. Their shape and orientation seem to be inherited from interactions between bottom currents and paleomorphologies expressed at the top of mass transport deposits. Their evolution is possibly driven by the intensity of bottom current activity that might have changed over time. Overall, this work presents an integrated approach combining seismic and sedimentological evidence to study the processes at the origin of contourite formation in the Demerara Plateau. Other regional factors, such as local slope values and slope instability, also control sedimentation

Description of a contourite depositional system on the Demerara Plateau: Results from geophysical data and sediment cores

The Demerara Plateau, belonging to the passive transform margin of French Guiana, was investigated during the IGUANES cruise in 2013. The objectives of the cruise were to explore the poorly-known surficial sedimentary column overlying thick mass transport deposits as well as to understand the factors controlling recent sedimentation. The presence of numerous bedforms at the seafloor was observed thanks to newly acquired IGUANES bathymetric, high resolution seismic and chirp data, while sediment cores allowed the characterization of the deposits covering the mass transport deposits. Modern oceanographic conditions were determined in situ, using mooring monitoring over a 10-month period. Our data indicate the presence of a Contourite Depositional System along the Demerara Plateau, most likely related to bottom current activity of the North Atlantic Deep Water (NADW). However, at the regional scale, large longitudinal waves parallel the NADW flow. Their shape and orientation seem to be inherited from interactions between bottom currents and paleomorphologies expressed at the top of mass transport deposits. Their evolution is possibly driven by the intensity of bottom current activity that might have changed over time. Overall, this work presents an integrated approach combining seismic and sedimentological evidence to study the processes at the origin of contourite formation in the Demerara Plateau. Other regional factors, such as local slope values and slope instability, also control sedimentation

Apport de la géophysique terrestre (géo-radar, sismique réfraction) pour l’aide à la gestion du trait de côte.

International audienc

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

International audienceCritical 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

Rapport de conjoncture 2024 - Section 18 du CoNRS (mandat 2021-2025): Questions clés et défis en Sciences de la Terre et des planètes

Ce rapport s'adresse à un large public allant des chercheurs et ingénieurs dans nos disciplines et d'autres domaines, aux étudiants et aux décideurs. Il vise à donner un panorama à jour des recherches en Sciences de la Terre et des outils structurant notre communauté. Il se base sur l'analyse d'environ un millier de dossiers (concours, promotions, évaluations individuelles et de laboratoires) et d'auditions émanant des chercheurs et des candidats de la section 18, ainsi que des propositions de médailles et d’accueil en délégation CNRS. A partir d’une sélection d'illustrations schématisant des exemples représentatifs de changements de paradigme, sont présentées quelques avancées réalisées ces dix dernières années et les défis scientifiques et méthodologiques, sans pouvoir être totalement exhaustifs

Rapport de conjoncture 2024 - Section 18 du CoNRS (mandat 2021-2025): Questions clés et défis en Sciences de la Terre et des planètes

Ce rapport s'adresse à un large public allant des chercheurs et ingénieurs dans nos disciplines et d'autres domaines, aux étudiants et aux décideurs. Il vise à donner un panorama à jour des recherches en Sciences de la Terre et des outils structurant notre communauté. Il se base sur l'analyse d'environ un millier de dossiers (concours, promotions, évaluations individuelles et de laboratoires) et d'auditions émanant des chercheurs et des candidats de la section 18, ainsi que des propositions de médailles et d’accueil en délégation CNRS. A partir d’une sélection d'illustrations schématisant des exemples représentatifs de changements de paradigme, sont présentées quelques avancées réalisées ces dix dernières années et les défis scientifiques et méthodologiques, sans pouvoir être totalement exhaustifs

Rapport de conjoncture 2024 - Section 18 du CoNRS (mandat 2021-2025): Questions clés et défis en Sciences de la Terre et des planètes

Ce rapport s'adresse à un large public allant des chercheurs et ingénieurs dans nos disciplines et d'autres domaines, aux étudiants et aux décideurs. Il vise à donner un panorama à jour des recherches en Sciences de la Terre et des outils structurant notre communauté. Il se base sur l'analyse d'environ un millier de dossiers (concours, promotions, évaluations individuelles et de laboratoires) et d'auditions émanant des chercheurs et des candidats de la section 18, ainsi que des propositions de médailles et d’accueil en délégation CNRS. A partir d’une sélection d'illustrations schématisant des exemples représentatifs de changements de paradigme, sont présentées quelques avancées réalisées ces dix dernières années et les défis scientifiques et méthodologiques, sans pouvoir être totalement exhaustifs

Rapport de conjoncture 2024 - Section 18 du CoNRS (mandat 2021-2025): Questions clés et défis en Sciences de la Terre et des planètes

Ce rapport s'adresse à un large public allant des chercheurs et ingénieurs dans nos disciplines et d'autres domaines, aux étudiants et aux décideurs. Il vise à donner un panorama à jour des recherches en Sciences de la Terre et des outils structurant notre communauté. Il se base sur l'analyse d'environ un millier de dossiers (concours, promotions, évaluations individuelles et de laboratoires) et d'auditions émanant des chercheurs et des candidats de la section 18, ainsi que des propositions de médailles et d’accueil en délégation CNRS. A partir d’une sélection d'illustrations schématisant des exemples représentatifs de changements de paradigme, sont présentées quelques avancées réalisées ces dix dernières années et les défis scientifiques et méthodologiques, sans pouvoir être totalement exhaustifs