Algorithme d’ordonnancement optimal basé sur la programmation dynamique pour les applications aux données parallèles sur des plates-formes hétérogènes

This report discusses a new algorithm for makespan minimization on situations where the workload can be partitioned among heterogeneous resources. Without making any assumptions regarding the behavior or shape of the functions giving the execution time on a resource, we are able to provide optimal solutions with a dynamic programming algorithm in O(T^2n) for a workload of T tasks and n heterogeneous resources. This report includes a short state of the art, the problem's model, the algorithm, and its optimality proof.Ce rapport discute d'un nouvel algorithme pour la minimisation du makespan dans des situations où la charge de travail peut être partitionnée entre des ressources hétérogènes. Sans faire aucune hypothèse sur le comportement ou la forme des fonctions donnant le temps d'exécution sur une ressource, nous sommes capables de fournir des solutions optimales avec un algorithme de programmation dynamique en O(T^2n) pour une charge de travail de T tâches et n ressources hétérogènes.Ce rapport comprend un bref état de l'art, le modèle du problème, l'algorithme, et sa preuve d'optimalité

ComprehensiveBench: a Benchmark for the Extensive Evaluation of Global Scheduling Algorithms

International audienceParallel applications that present tasks with imbalanced loads or complex communication behavior usually do not exploit the underlying resources of parallel platforms to their full potential. In order to mitigate this issue, global scheduling algorithms are employed. As finding the optimal task distribution is an NP-Hard problem, identifying the most suitable algorithm for a specific scenario and comparing algorithms are not trivial tasks. In this context, this paper presents ComprehensiveBench, a benchmark for global scheduling algorithms that enables the variation of a vast range of parameters that affect performance. ComprehensiveBench can be used to assist in the development and evaluation of new scheduling algorithms, to help choose a specific algorithm for an arbitrary application, to emulate other applications, and to enable statistical tests. We illustrate its use in this paper with an evaluation of Charm++ periodic load balancers that stresses their characteristics

ComprehensiveBench: a Benchmark for the Extensive Evaluation of Global Scheduling Algorithms

International audienceParallel applications that present tasks with imbalanced loads or complex communication behavior usually do not exploit the underlying resources of parallel platforms to their full potential. In order to mitigate this issue, global scheduling algorithms are employed. As finding the optimal task distribution is an NP-Hard problem, identifying the most suitable algorithm for a specific scenario and comparing algorithms are not trivial tasks. In this context, this paper presents ComprehensiveBench, a benchmark for global scheduling algorithms that enables the variation of a vast range of parameters that affect performance. ComprehensiveBench can be used to assist in the development and evaluation of new scheduling algorithms, to help choose a specific algorithm for an arbitrary application, to emulate other applications, and to enable statistical tests. We illustrate its use in this paper with an evaluation of Charm++ periodic load balancers that stresses their characteristics

Reducing Global Schedulers' Complexity Through Runtime System Decoupling

National audienceGlobal schedulers are components used in parallel solutions, specially in dynamic applications, to optimize resource usage. Nonetheless, their development is a cumbersome process due to necessary adaptations to cope with the programming interfaces and abstractions of runtime systems. This paper proposes a model to dissociate sched-ulers from runtime systems to lower software complexity. Our model is based on the scheduler breakdown into modular and reusable concepts that better express the scheduler requirements. Through the use of meta-programming and design patterns, we were able to achieve fully reusable workload-aware scheduling strategies with up to 63% fewer lines of code with negligible run time overhead

Selection Signatures in Worldwide Sheep Populations

The diversity of populations in domestic species offers great opportunities to study genome response to selection. The recently published Sheep HapMap dataset is a great example of characterization of the world wide genetic diversity in sheep. In this study, we re-analyzed the Sheep HapMap dataset to identify selection signatures in worldwide sheep populations. Compared to previous analyses, we made use of statistical methods that (i) take account of the hierarchical structure of sheep populations, (ii) make use of linkage disequilibrium information and (iii) focus specifically on either recent or older selection signatures. We show that this allows pinpointing several new selection signatures in the sheep genome and distinguishing those related to modern breeding objectives and to earlier post-domestication constraints. The newly identified regions, together with the ones previously identified, reveal the extensive genome response to selection on morphology, color and adaptation to new environments