Randomizing task placement does not randomize traffic (enough)
Ana Jokanović, Bogdan Prisacari, Germán Rodríguez, Cyriel Minkenberg · 2013
Dragonflies are one of the most promising topologies for the Exascale effort for their scalability and cost. Dragonflies achieve very high throughput under uniform traffic, but have a pathological behavior under other regular traffic patterns, some of them very common in HPC applications. A recent study showed that randomization of task placement can make pathological, regular (multi-dimensional stencil) traffic patterns behave similar to uniform traffic.