Comparison of Batch Scheduling for Identical Multi-Tasks Jobs on Heterogeneous Platforms

International audienceIn this paper we consider the scheduling of a batch of the same job on a heterogeneous execution platform. A job is represented by a directed acyclic graph without forks (intree) but with typed tasks. The execution resources are distributed and each resource can carry out a set of task types. The objective function is to minimize the makespan of the batch execution. Three algorithms are studied in this context: an on-line algorithm, a genetic algorithm and a steady-state algorithm. The contribution of this paper is on the experimental analysis of these algorithms and on their adaptation to the context. We show that their performances depend on the size of the batch and on the characteristics of the execution platform

Adaptation d'un algorithme optimal d'ordonnancement en régime permanent pour des lots bornés

International audienceLe contexte de cet article est l ordonnancement de lots bornes de travaux identiques sur une plate-forme d execution heterogene comme la grille. Les travaux executes sont des graphes de t?ches orientes et sans cycle (DAG), en forme d anti-arbre. Les t?ches sont de plusieurs types et les n{oe}uds de la plate-forme ne sont pas toujours en mesure d executer tous les types de t?ches. Le probleme de minimisation du temps d execution d un lot est un probleme NP-Complet. Sous l angle du regime permanent, il est possible de decrire le probleme sous la forme d un programme lineaire donnant une solution optimale pour l ordonnancement cyclique de lots infinis. Lorsque les lots sont bornes, les resultats restent bons bien que sous optimaux. Nous montrons ici que les phases d initialisation et de terminaison ajoutent un sur-co?t qui penalise le temps global d execution. Nous montrons ensuite le lien entre la taille de ces phases et la taille de la periode de l ordonnancement cyclique et donnons un algorithme permettant le calcul de la periode minimale. Des experimentations, obtenues par simulations avec SimGrid, illustrent en fin d article le gain apporte par le choix d une periode minimal

Steady-State for Batches of Identical Task Graphs

International audienceIn this paper, we focus on the problem of scheduling batches of identical task graphs on a heterogeneous platform, when the task graph consists in a tree. We rely on steady-state scheduling, and aim at reaching the optimal throughput of the system. Contrarily to previous studies, we concentrate upon the scheduling of batches of limited size. We try to reduce the processing time of each instance, thus making steady-state scheduling applicable to smaller batches. The problem is proven NP-complete, and a mixed integer program is presented to solve it. Then, different solutions, using steady-state scheduling or not, are evaluated through comprehensive simulations