Providing differentiated services, congestionmanagement, and deadlock freedom in dragonfly networks with adaptive routing

摘要

The number of endnodes in high-performance computing systems has grown significantly in thernlast years. Hence, the interconnection network has become an essential issue as it may end uprnbeing the system bottleneck if it is not properly designed. In that sense, the Dragonfly topologyrnhas become very popular for interconnecting high-performance computing systems in the lastrnyearsbecause it offers high performance at an affordable cost.However,whenusing deterministicrnminimal-path routing, this topology is not able to offer a high performance under certain trafficrnconditions. This problem can be solved by using oblivious or adaptive routing. However, therernare no congestionmanagement techniques specially tailored toDragonfly topologies using obliviousrnor adaptive routing. Note that in congestion situations, the Dragonfly performance may droprnbecause of the head-of-line blocking effect. This effect could be evenmore dangerous in systemsrnwhere several applications with different priorities coexist. In thiswork we propose several techniquesrnespecially designed for providing differentiated services and congestion management inrnDragonfly networks using oblivious or adaptive routing. First, we propose the hierarchical 3-levelrnqueuing queuing scheme, which configures several virtual channels distributed into 3 virtual networksrnto reduce the head-of-line blocking while deadlocks derived from the routing algorithmrnare prevented. Second, we extend hierarchical 3-level queuing to provide differentiated servicesrnthrough 2 different solutions. Finally, some experiments are performed to show the benefitsrnobtained by using the proposed techniques.