STR2RTS: Refactored StreamIT Benchmarks into Statically Analyzable Parallel Benchmarks for WCET Estimation & Real-Time Scheduling

International audienceWe all had quite a time to find non-proprietary architecture-independent exploitable parallel benchmarks for Worst-Case Execution Time (WCET) estimation and real-time scheduling. However , there is no consensus on a parallel benchmark suite, when compared to the single-core era and the Mälardalen benchmark suite [12]. This document bridges part of this gap, by presenting a collection of benchmarks with the following good properties: (i) easily analyzable by static WCET estimation tools (written in structured C language, in particular neither goto nor dynamic memory allocation, containing flow information such as loop bounds); (ii) independent from any particular run-time system (MPI, OpenMP) or real-time operating system. Each benchmark is composed of the C source code of its tasks, and an XML description describing the structure of the application (tasks and amount of data exchanged between them when applicable). Each benchmark can be integrated in a full end-to-end empirical method validation protocol on multi-core architecture. This proposed collection of benchmarks is derived from the well known StreamIT [21] benchmark suite and will be integrated in the TACleBench suite [11] in a near future. All these benchmarks are available at https://gitlab.inria.fr/brouxel/STR2RTS

The Heptane Static Worst-Case Execution Time Estimation Tool

Estimation of worst-case execution times (WCETs) is required to validate the temporal behavior of hard real time systems. Heptane is an open-source software program that estimates upper bounds of execution times on MIPS and ARM v7 architectures, offered to the WCET estimation community to experiment new WCET estimation techniques. The software architecture of Heptane was designed to be as modular and extensible as possible to facilitate the integration of new approaches. This paper is devoted to a description of Heptane, and includes information on the analyses it implements, how to use it and extend it

Traduire pour le visiteur : l’exemple du Louvre

Recourir à la traduction, rien de plus naturel dans un musée qui accueille majoritairement des visiteurs étrangers. Mais au fond, pourquoi traduire ? La question peut sembler provocante mais elle mérite tout de même d’être posée. Quels supports et dans quelles langues ? D’un point de vue organisationnel, comment le Louvre est-il passé d’une coordination ponctuelle à une coordination transversale de la traduction à l’échelle du musée ? Quelles sont les contraintes et les exigences de la traduc..

Glacial influence on the geochemistry of riverine iron fluxes to the Gulf of Alaska and effects of deglaciation

This paper is not subject to U.S. copyright. The definitive version was published in Geophysical Research Letters 38 (2011): L16605, doi:10.1029/2011GL048367.Riverine iron (Fe) derived from glacial weathering is a critical micronutrient source to ecosystems of the Gulf of Alaska (GoA). Here we demonstrate that the source and chemical nature of riverine Fe input to the GoA could change dramatically due to the widespread watershed deglaciation that is underway. We examine Fe size partitioning, speciation, and isotopic composition in tributaries of the Copper River which exemplify a long-term GoA watershed evolution from one strongly influenced by glacial weathering to a boreal-forested watershed. Iron fluxes from glacierized tributaries bear high suspended sediment and colloidal Fe loads of mixed valence silicate species, with low concentrations of dissolved Fe and dissolved organic carbon (DOC). Iron isotopic composition is indicative of mechanical weathering as the Fe source. Conversely, Fe fluxes from boreal-forested systems have higher dissolved Fe concentrations corresponding to higher DOC concentrations. Iron colloids and suspended sediment consist of Fe (hydr)oxides and organic complexes. These watersheds have an iron isotopic composition indicative of an internal chemical processing source. We predict that as the GoA watershed evolves due to deglaciation, so will the source, flux, and chemical nature of riverine Fe loads, which could have significant ramifications for Alaskan marine and freshwater ecosystems.We appreciate support from the USGS CMGP, NCCWSC, and the Mendenhall Postdoctoral Program

Time-series analysis of two hydrothermal plumes at 9°50′N East Pacific Rise reveals distinct, heterogeneous bacterial populations

Author Posting. © The Author(s), 2011. This is the author's version of the work. It is posted here by permission of John Wiley & Sons for personal use, not for redistribution. The definitive version was published in Geobiology 10 (2012): 178-192, doi:10.1111/j.1472-4669.2011.00315.xWe deployed sediment traps adjacent to two active hydrothermal vents at 9°50’N on the East Pacific Rise (EPR) to assess variability in bacterial community structure associated with plume particles on the time scale of weeks to months, to determine if an endemic population of plume microbes exists, and to establish ecological relationships between bacterial populations and vent chemistry. Automated rRNA intergenic spacer analysis (ARISA) indicated there are separate communities at the two different vents and temporal community variations between each vent. Correlation analysis between chemistry and microbiology indicated that shifts in the coarse particulate (>1 mm) Fe/(Fe+Mn+Al), Cu, V, Ca, Al, 232Th, and Ti as well as fine-grained particulate (<1 mm) Fe/(Fe+Mn+Al), Fe, Ca and Co are reflected in shifts in microbial populations. 16S rRNA clone libraries from each trap at three time points revealed a high percentage of Epsilonproteobacteria clones and hyperthermophilic Aquificae. There is a shift towards the end of the experiment to more Gammaproteobacteria and Alphaproteobacteria, many of whom likely participate in Fe and S cycling. The particle attached plume environment is genetically distinct from the surrounding seawater. While work to date in hydrothermal environments has focused on determining the microbial communities on hydrothermal chimneys and the basaltic lavas that form the surrounding seafloor, little comparable data exists on the plume environment that physically and chemically connects them. By employing sediment traps for a time series approach to sampling, we show that bacterial community composition on plume particles changes on time scales much shorter than previously known.This work was supported by the NSF Marine Geology and Geophysics program, the Science and Technology program, and the Gordon and Betty Moore Foundation

The TeamPlay project : analysing and optimising time, energy, and security for cyber-physical systems

Funding: This work was supported by the EU Horizon-2020 project TeamPlay (https://www.teamplay-h2020.eu), grant #779882.Non-functional properties, such as energy, time, and security (ETS) are becoming increasingly important for the programming of Cyber-Physical Systems (CPS). This paper describes TeamPlay, a research project funded under the EU Horizon 2020 programme between January 2018 and June 2021.TeamPlay aimed to provide the system designer with a toolchain for developing embedded applications where ETS properties are first-class citizens, allowing the developer to reflect directly on energy, time and security properties at the source code level. In this paper we give an overview of the TeamPlay methodology, introduce the challenges and solutions of our approach and summarise the results achieved. Overall, applying our TeamPlay methodology led to an improvement of up to 18% performance and 52% energy usage over traditional approaches.Postprin

Les projets de partenariats public privé au Québec : une étude de cas

Le partenariat public privé, autrement appelé PPP, est une méthode de gérance de projet public de plus en plus utilisée. Au Québec, le gouvernement a récemment encouragé le recours à ce type de collaboration dans son plan de modernisation et a créé une structure à même d' encadrer les PPP et de formaliser leur gestion: l'Agence des PPP. Faire travailler ensemble deux structures à l'organisation et aux objectifs différents est un défi pour chaque projet. Au travers l'étude d'un cas, à savoir la construction du nouveau campus universitaire de l'UQAR - Campus de Lévis par le promoteur AMT, ce travail compare la réalité d'un projet avec l' approche théorique des PPP. Cette comparaison se fait sur trois grands axes: la typologie, les facteurs critiques de succès et la phase de conception du projet. Aussi l'on se rend compte que chaque partenariat est unique de par la singularité des acteurs qu'il associe, la synergie qu'il développe et le cadre dans lequel il prend place. Il parait difficile de calquer un modèle de réussite sur les PPP, car même si l'on croit y retrouver la dynamique classique de la gestion de projet, ce nouveau mode de gérance a bel et bien ses propres caractéristiques

Minimiser l’impact des communications lors de l’ordonnancement d’application temps-réels sur des architectures multi-cœurs

Multi-core architectures using scratch pad memories are very attractive to execute embedded time-critical applications, because they offer a large computational power. However, ensuring that timing constraints are met on such platforms is challenging, because some hardware resources are shared between cores. When targeting the bus connecting cores and external memory, worst-case sharing scenarios are too pessimistic.This thesis propose strategies to reduce this pessimism. These strategies offer to both improve the accuracy of worst-case communication costs, and to exploit hardware parallel capacities by overlapping computations and communications. Moreover, fragmenting the latter allow to increase overlapping possibilities.Les architectures multi-coeurs utilisant des mémoire bloc-notes sont des architectures attrayantes pour l’exécution des applications embarquées temps-réel, car elles offrent une grande capacité de calcul. Cependant, les systèmes temps-réel nécessitent de satisfaire des contraintes temporelles, ce qui peut être compliqué sur ce type d’architectures à cause notamment des ressources matérielles physiquement partagées entre les coeurs. Plus précisément, les scénarios de pire cas de partage du bus de communication entre les coeurs et la mémoire externe sont trop pessimistes.Cette thèse propose des stratégies pour réduire ce pessimisme lors de l’ordonnancement d’applications sur des architectures multi-coeurs. Tout d’abord, la précision du pire cas des coûts de communication est accrue grâce aux informations disponibles sur l’application et l’état de l’ordonnancement en cours. Ensuite, les capacités de parallélisation du matériel sont exploitées afin de superposer les calculs et les communications. De plus, les possibilités de superposition sont accrues par le morcellement de ces communications