Models for scheduling on large scale platforms: which policy for which application?

Summary form only given. In recent years, there was a huge development of low cost large scale parallel systems. The design of efficient parallel algorithms has to be reconsidered to take into account new parameters of such execution platforms which are characterized by a larger number of heterogeneous processors, often organized as hierarchical subsystems. Alternative computational models have been designed to take into account these new characteristics. Parallel tasks model × PT in short - is a promising alternative for scheduling parallel applications. Another way of looking at the problem (which is somehow a dual view) is the divisible load model (DL) where an application is considered as a collection of a large number of elementary - sequential - computing units. These two new views of the problem allow us to consider communications implicitly or to mask them, leading to more tractable problems. This paper, first, presents some approximation algorithms for the PT model with a special emphasis on new execution platforms. We show how to mix these results with the DL model to manage the resources of an actual computational grid of 600 processors.