Analyse et modélisation des communications concurrentes dans les réseaux haute performance. (Analysis and modelling of concurrent communications over high performance networks)

Analysis and modelling of concurrent communicationsover high performance networks. Improving processor capabilities by increasing the number of cores produces sharing effects over com-puter components among core requests. Furthermore, parallel applications from scientific fields attempt tofully exploit the resources of parallel architectures. Therefore, understanding resource-sharing phenomenonbecomes one major issue for actual parallel architectures.These new behaviours of resource sharing are hard to analyse and to predict. In this work, we studythe problem of network sharing. Clusters use dedicated high performance networks such as Gigabit Ether-net, Myrinet or Quadrics. Simultaneous executions of application tasks create concurrent access over thenetwork. Their effects lead to performance leaks because of bandwidth network segmentation among com-munications.In this context, we present a deep analysis of concurrent behaviours for Quadrics, Myrinet and Giga-bit Ethernet. This analysis aims to the definition of predictive models based on the concept of bandwidthsharing. In addition, we integrate such models in a simulation process for predicting concurrent communi-cation impacts resulting of scientific application runs. Predicting concurrent behaviour leads, in scientificand technologic areas, to a better knowledge of application needs and, in industrial context, to advancecluster solutions adjusted to customer requirements.