Slim Fly: A Cost Effective Low-Diameter Network Topology (1912.08968v2)

Abstract: We introduce a high-performance cost-effective network topology called Slim Fly that approaches the theoretically optimal network diameter. Slim Fly is based on graphs that approximate the solution to the degree-diameter problem. We analyze Slim Fly and compare it to both traditional and state-of-the-art networks. Our analysis shows that Slim Fly has significant advantages over other topologies in latency, bandwidth, resiliency, cost, and power consumption. Finally, we propose deadlock-free routing schemes and physical layouts for large computing centers as well as a detailed cost and power model. Slim Fly enables constructing cost effective and highly resilient datacenter and HPC networks that offer low latency and high bandwidth under different HPC workloads such as stencil or graph computations.

• The paper presents Slim Fly’s main contribution as a cost-effective low-diameter topology that enhances latency and bandwidth in large-scale networks.
• It details a rigorous design using solutions to the degree-diameter problem and MMS graphs to minimize hardware requirements and improve routing efficiency.
• The study demonstrates up to 25-30% savings in cost and energy consumption, underscoring its potential for scalable deployment in datacenters and HPC systems.

An Overview of Slim Fly: An Efficient Network Topology for Datacenters and HPC Systems

Slim Fly presents a novel network topology designed to address the demands of contemporary datacenter and high-performance computing (HPC) networks, where latency, bandwidth, and energy efficiency are paramount. The proposed topology is anchored on reducing network diameter to nearly the theoretical minimum, thereby enhancing communication efficiency.

Conceptual Framework and Design Objectives

The Slim Fly network is constructed based on mathematical solutions to the degree-diameter problem, leading to a topology with significantly reduced diameter. This reduction in diameter corresponds to decreased latency, lower energy consumption, and lesser costs due to minimized hardware requirements such as routers and connections. The slim design not only ensures high bandwidth but also enhances resiliency against link failures, which are crucial in large-scale computing environments.

Analytical Insights and Performance Metrics

The paper offers a rigorous analysis of Slim Fly, contrasting it with traditional and state-of-the-art network topologies like Fat Trees and Dragonfly networks. It underscores Slim Fly's superiority by presenting metrics such as improved latency, increased bandwidth, and resilient fault tolerance characteristics. Specifically, the paper highlights that Slim Fly achieves a network diameter of two, substantially outperforming other topologies in this regard. Additionally, the use of a low-diameter design metaphorically closes the gap to the Moore Bound, representing an optimal configuration in terms of network radices.

Topological Specifics and Routing

The paper introduces various network configurations built upon MMS graphs, which closely achieve the degree-diameter optimality. An associated merit of Slim Fly is its compatibility with existing router technologies, allowing the construction of networks with up to tens of millions of endpoints with minimal latency increments.

The work also delineates several deadlock-free routing schemes, including minimal and non-minimal strategies like UGAL-G and UGAL-L, enhancing the practicality and adaptive efficiency of Slim Fly in real-world applications. These routing strategies effectively balance load even under adverse traffic patterns, ensuring optimal network performance.

Cost and Power Efficiencies

The proposed topology promises substantial reductions in both network deployment costs and operational power consumption, primarily due to its efficient cabling and routing requirements. By pioneering a layout that minimizes the use of costly fiber optic cables while leveraging high-radix routers, Slim Fly holds a practical edge over other topologies, projecting up to 25-30% savings in both cost and energy consumption.

Implementation Potential and Future Directions

Slim Fly paves the way for cost-effective deployment strategies in datacenters, harmoniously integrating with modular system architectures akin to Dragonfly configurations. Its scalable and adaptable facade supports incremental endpoint additions with nominal performance penalties, underscoring the topology's robustness and flexibility.

Moreover, the paper suggests that ongoing advancements in fiber optic technology and the availability of high-radix router technologies will likely amplify Slim Fly’s advantages, establishing it as a compelling choice for future network architectures.

Conclusion

The Slim Fly topology, as elucidated in the paper, offers a significant advancement in the design of network infrastructures, particularly for applications where reducing operational costs and enhancing performance are decisive. By aligning network design principles with mathematical optimization strategies, the paper sets a precedent for future innovations in network topology design, offering substantial benefits to the field of supercomputing and large-scale computing networks.