A new switch buffer architecture for dragonfly networks
Alejandro Cano, Cristóbal Camarero, Carmen Martínez, Ramón Beivide · Journal of Parallel and Distributed Computing · 2025
• LUGH is a new buffer architecture for Dragonfly Interconnection Networks. • LUGH achieves high performance and fairness in Dragonfly networks. • A theoretical model to compare the fairness of buffer architectures has been obtained. • Theoretical throughput calculations align with simulation results. • LUGH is a cost-effective solution which outperforms other VC mechanisms in most scenarios. Dragonfly networks offer a viable solution for large-scale supercomputers and datacenters. However, developing efficient routing mechanisms for these networks presents significant challenges. Current solutions often lead to unstable network behavior due to congestion and fairness issues, exacerbating performance variability and the tail-latency problem. An analysis of the topology and its standard deadlock avoidance mechanisms reveals that server access to global network links varies based on their location in the network, resulting in throughput unfairness. To address this issue, this paper introduces a novel switch buffer architecture which reduces head-of-line blocking and enhances fairness, to significantly improve overall network performance. Despite offering comparable cost to existing solutions, the proposed buffer architecture proves superior performance. Real-world synthetic simulations scenarios further confirm these findings, showing performance improvements between 10 % and 47 % against conventional solutions in medium sized Dragonflies.