Power consumption management in fat-tree interconnection networks

Abstract

As higher communication bandwidth is required in current designs of high performance parallel computers, the amount of power consumed by the interconnection network also increases. Fat-tree is one of the most popular topologies in high performance interconnection networks aiming at low latency, efficient collective communication and scalability. We present a new methodology for managing power consumption of fat-tree interconnection networks. Our proposal is based on dynamically adjusting available network bandwidth according to traffic requirements. To meet this goal, we define a mechanism for managing the operating status of network links as a function of network load. Our main contributions include a complete definition of the mechanism and a tuning methodology based on its sensitivity and aggressiveness in terms of potential power savings. Results show that our proposal can provide significant power savings (up to 67% in a 4-ary 4-tree) with no changes in the underlying routing algorithm, with minimal impact on network performance. Experiments conducted on a 16-ary 3-tree topology provide up to 36% energy savings with performance degradation below 1.10%.