High-radix crossbar switches enabled by Proximity Communication

Eberle,; Garcia, Jose; Flich,; Duato, J.; Drost, Jarno; Gura,; Hopkins, David; Olesinski,

doi:10.1109/sc.2008.5219754

Cited by 12 publications

(7 citation statements)

References 17 publications

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“…Based on our previously proposed router microarchitecture [11], radix-64 Cray YARC router [13] was one of the first high-radix routers implemented and used in the recently announced Cray BlackWidow system [1]. Mellanox has recently introduced high-radix routers and researchers at SUN Microsystems have investigated creating high-radix switches using proximity communication [5]. With the availability of high-radix routers, the topology that efficiently exploits high-radix routers will have to be a significant departure from previous low-radix networks that employed 2-D or 3-D torus topologies.…”

Section: Significancementioning

confidence: 99%

Cost-Efficient Dragonfly Topology for Large-Scale Systems

Kim

Dally

Scott³

et al. 2009

Optical Fiber Communication Conference and National Fiber Optic Engineers Conference

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Evolving technology and increasing pin-bandwidth motivate the use of high-radix routers to reduce the diameter, latency, and cost of interconnection networks. This migration from low-radix to high-radix routers is demonstrated with the recent introduction of high-radix routers and they are expected to impact networks used in large-scale systems such as multicomputers and data centers. As a result, a scalable and a cost-efficient topology is needed to properly exploit high-radix routers.High-radix networks require longer cables than their low-radix counterparts. Because cables dominate network cost, the number of cables, and particularly the number of long, global cables should be minimized to realize an efficient network. In this paper, we introduce the dragonfly topology which uses a group of high-radix routers as a virtual router to increase the effective radix of the network. With this organization, each minimally routed packet traverses at most one global channel. By reducing global channels, a dragonfly reduces cost by 20% compared to a flattened butterfly and by 52% compared to a folded Clos network in configurations with ≥ 16K nodes.The paper also introduces two new variants of global adaptive routing that enable load-balanced routing in the dragonfly. Each router in a dragonfly must make an adaptive routing decision based on the state of a global channel connected to a different router. Because of the indirect nature of this routing decision, conventional adaptive routing algorithms give degraded performance. We introduce the use of selective virtual-channel discrimination and the use of credit round-trip latency to both sense and signal channel congestion. The combination of these two methods gives throughput and latency that approaches that of an ideal adaptive routing algorithm. SummaryThe interconnection network plays a critical role in the cost and performance of a scalable multiprocessor. Previous interconnection networks have been built with low-radix routers -i.e. routers with a small number of ports. As a result, these networks used low-radix topologies such as 2-D or 3-D mesh or torus networks. Examples of machines employing such networks include the Cray T3D, T3E, and XT3. Earlier work [4,2] showed that, for the packaging and technology constraints of the 80s and 90s, low-radix networks provide optimal latency for a given cost. This was true with the relatively low pin bandwidth available during the 80s and the early 90s. It is no longer the case.Over the past 20 years, the pin bandwidth of router chips has increased by approximately an order of magnitude every 5 years ( Figure 1) -a rate very similar to Moore's Law. This increase in bandwidth is a result of both an increase in the signaling rate and an increase in the number of signals. High-radix routers have been shown to take advantage of this increasing bandwidth by dividing the bandwidth into larger number of narrow ports [11]. In contrast, low-radix routers divide the bandwidth into a smaller number of wide ports. The Cray Black...

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Section: Significancementioning

confidence: 99%

Cost-Efficient Dragonfly Topology for Large-Scale Systems

Kim

Dally

Scott³

et al. 2009

Optical Fiber Communication Conference and National Fiber Optic Engineers Conference

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“…In recent years, many studies have been conducted in the field of high-radix routers [3,5,6,[12][13][14][15]. However, none of them provides an accurate, broad and holistic overview of high-radix MINs.…”

Section: Introductionmentioning

confidence: 99%

Flattening: An efficient approach to improving the performance of conventional MINs

Rezazadeh

Safaei

Moazez³

2015

Microelectronics Journal

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“…Increasing integrated-circuit pin bandwidth has motivated a corresponding increase in the degree or radix of interconnection networks and their routers [1], and the new chip interconnect technology called proximity communication that offers unparalleled chip IO density has enabled the implementation J.-H. Park ( ) School of Computer Science and Engineering, Chung-Ang University, 221 Heukseok-Dong, Dongjak-Ku, Seoul 156-756, Republic of Korea e-mail: hyunie@cau.ac.kr of high-radix crossbar switches [2]. High-radix multistage interconnection networks have been widely used as the interconnection structures for parallel supercomputer systems and cluster computers.…”

Section: Introductionmentioning

confidence: 99%

“…Recently, the dramatic increase in chip IO bandwidth made possible by proximity communication allows the implementation of high-radix crossbar switches [2]. However, the architecture still needs improvement.…”

Section: Introductionmentioning

confidence: 99%

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The deflection self-routing Delta network: a dynamically fault-tolerant high-radix multistage interconnection network

Park

2009

J Supercomput

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High-radix multistage interconnection networks are popular interconnection technologies for parallel supercomputers and cluster computers. In this paper, we presented a new dynamically fault-tolerant high-radix multistage interconnection network using a fully-adaptive self-routing. To devise the fully-adaptive self-routing for recovering the misrouting around link faults in such network, we introduce an abstract algebraic analysis of the topological structure of the high-radix Delta network. The presented interconnection network provides multiple paths by using all the links of all the stages of the network. We also present a mathematical analysis of the reliability of the interconnection network for quantitative comparison against other networks. The MTTF of 64 × 64 network proposed is 2.2 times greater than that of the cyclic Banyan network. The hardware cost of the proposed network is half that of the cyclic Banyan network and the 2D ring-Banyan network.

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High-radix crossbar switches enabled by Proximity Communication

Cited by 12 publications

References 17 publications

Cost-Efficient Dragonfly Topology for Large-Scale Systems

Cost-Efficient Dragonfly Topology for Large-Scale Systems

Flattening: An efficient approach to improving the performance of conventional MINs

The deflection self-routing Delta network: a dynamically fault-tolerant high-radix multistage interconnection network

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