vFtree - A Fat-Tree Routing Algorithm Using Virtual Lanes to Alleviate Congestion

IEEE Trans. Parallel Distrib. Syst.

García

Quiles

et al. 2013

As parallel computing systems increase in size, the interconnection network is becoming a critical subsystem. The current trend in network design is to use as few components as possible to interconnect the end nodes, thereby reducing cost and power consumption. However, this increases the probability of congestion appearing in the network. As congestion may severely degrade network performance, the use of a congestion management mechanism is becoming mandatory in modern interconnects. One of the most cost-effective proposals to deal with the problems derived from congestion situations is the Regional Explicit Congestion Notification (RECN) strategy, based on using special queues to totally isolate the packet flows which contribute to congestion, thereby preventing the Head-of-Line (HoL) blocking effect that these flows may cause to others. Unfortunately, RECN requires the use of source-based routing, thus not being suitable for interconnects with distributed routing, like InfiniBand. Although some RECN-like mechanisms have been proposed for distributed-routing networks, they are not scalable due to the huge amount of control memory that they require in medium-size or large networks. In this paper, we propose Distributed-Routing-Based Congestion Management (DRBCM), a new scalable technique which, following the RECN principles, totally prevents congestion from producing HoL-blocking in multistage interconnection networks (MINs) using tag-based distributed routing. Simulation results indicate that, regardless of network size, DRBCM presents small resource requirements to keep network performance at maximum level even in scenarios of heavy congestion, where it utterly outperforms (with a gain up to 70 percent) current solutions for distributed-routing networks, like the InfiniBand congestion-control mechanism based on injection throttling. Thus, DRBCM is an efficient, cost-effective, and scalable solution for congestion management.

Section: Simulation Modelmentioning

confidence: 94%

Section: Motivationmentioning

confidence: 99%

Section: Simulation Modelmentioning

confidence: 99%

Section: Simulation Modelmentioning

confidence: 99%

See 2 more Smart Citations

An Effective and Feasible Congestion Management Technique for High-Performance MINs with Tag-Based Distributed Routing

IEEE Trans. Parallel Distrib. Syst.

García

Quiles

et al. 2013

“…and topology-aware solutions (e.g. OBQA [23], vFTree [24], and Band-Based Queuing (BBQ) [25]). Solutions from the latter group have been specially designed for a specific topology (and, in general, also for a specific routing algorithm) so that they take advantage of their topology-awareness to use network resources more efficiently than topology-agnostic solutions.…”

Section: Congestion Managementmentioning

confidence: 99%

Combining HoL-blocking avoidance and differentiated services in high-speed interconnects

Yébenes

2014 21st International Conference on High Performance Computing (HiPC)

Gómez

et al. 2014

Current high-performance platforms such as Datacenters or High-Performance Computing systems rely on highspeed interconnection networks able to cope with the everincreasing communication requirements of modern applications. In particular, in high-performance systems that must offer differentiated services to applications which involve traffic prioritization, it is almost mandatory that the interconnection network provides some type of Quality-of-Service (QoS) and CongestionManagement mechanism in order to achieve the required network performance. Most current QoS and Congestion-Management mechanisms for high-speed interconnects are based on using the same kind of resources, but with different criteria, resulting in disjoint types of mechanisms. By contrast, we propose in this paper a novel, straightforward solution that leverages the resources already available in InfiniBand components (basically Service Levels and Virtual Lanes) to provide both QoS and Congestion Management at the same time. This proposal is called CHADS (Combined HoL-blocking Avoidance and Differentiated Services), and it could be applied to any network topology. From the results shown in this paper for networks configured with the novel, cost-efficient KNS hybrid topology, we can conclude that CHADS is more efficient than other schemes in reducing the interferences among packet flows that have the same or different priorities.

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

Yébenes

Concurrency and Computation

García

et al. 2016

SummaryThe number of endnodes in high‐performance computing systems has grown significantly in the last years. Hence, the interconnection network has become an essential issue as it may end up being the system bottleneck if it is not properly designed. In that sense, the Dragonfly topology has become very popular for interconnecting high‐performance computing systems in the last years because it offers high performance at an affordable cost. However, when using deterministic minimal‐path routing, this topology is not able to offer a high performance under certain traffic conditions. This problem can be solved by using oblivious or adaptive routing. However, there are no congestion management techniques specially tailored to Dragonfly topologies using oblivious or adaptive routing. Note that in congestion situations, the Dragonfly performance may drop because of the head‐of‐line blocking effect. This effect could be even more dangerous in systems where several applications with different priorities coexist. In this work we propose several techniques especially designed for providing differentiated services and congestion management in Dragonfly networks using oblivious or adaptive routing. First, we propose the hierarchical 3‐level queuing queuing scheme, which configures several virtual channels distributed into 3 virtual networks to reduce the head‐of‐line blocking while deadlocks derived from the routing algorithm are prevented. Second, we extend hierarchical 3‐level queuing to provide differentiated services through 2 different solutions. Finally, some experiments are performed to show the benefits obtained by using the proposed techniques.