### Early evaluation of direct large-scale InfiniBand networks with adaptive routing

#### Abstract

We assess the problem of choosing optimal direct topology for InfiniBand networks in terms of performance. Newest topologies like Dragonfly, Flattened butterfly and Slim Fly are considered, as well as standard Tori and Hypercubes.We consider some reasonable extensions to InfiniBand hardware which could be implemented by vendors easily and may allow reasonable routing algorithms for such topologies. A number of routing algorithms are proposed and compared for

various traffic patterns. Mapping algorithms for Dragonfly and Flattened Butterfly are proposed. Based on this research it has been decided to use Flattened Butterfly topology for system #22 in November 2014 Top 500 list.

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