The Design and Implementation of Open-MX

Brice Goglin
Seminar

Open-MX is a message passing stack that offers the Myrinet Express features on top of regular Ethernet hardware. We will see what problems one can encounter when trying to mimic high-speed network capabilities without having advanced hardware support underneath. Several solutions based on I/OAT copy offload, interrupt affinities, and multiqueue support will be discussed. Finally, we will see how working on intra-node communication in Open-MX lead to designing the knem kernel module which aims at improving large message performance in MPICH2/Nemesis.