Efcient inter-device data-forwarding in the Madeleine communication library

Interconnecting multiple clusters with a high speed net-work to form a single heterogeneous architecture (i.e. a cluster of clusters) is currently a hot issue. Consequently, new runtime systems that are able to simultaneously deal with multiple high speed networks within the same appli-cation have to be designed. This paper presents how we did extend an existing multi-device communication library with fast internal data-forwarding capabilities on gateway nodes. On top of that, efficient high-level routing mecha-nisms can be implemented. Our approach is easily appli-cable to many network protocols and is completely inde-pendant from the application code. Efficiency is achieved by avoiding extra data copies when possible and by using pipelining techniques. The preliminary experiments show that the observed inter-cluster bandwidth is close to the one that can be delivered by the hardware.