Routing Keys

The network plays a key role in High-Performance Computing (HPC) system efficiency. Unfortunately, current HPC routing solutions are not application-aware, and therefore cannot deal with the sudden HPC traffic bursts and their resulting congestion peaks. To address this problem, we introduce Routing Keys, a scalable routing paradigm for HPC networks that decouples intra- and inter-application flow contention. Our Application Routing Key (ARK) algorithm proactively allows each self-aware application to route its flows according to a predetermined routing key, i.e., its own intra-application contention-free routing. In addition, in our Network Routing Key (NRK) algorithm, a centralized scheduler chooses between several routing keys for the communication phases of each application, and therefore reduces inter-application contention while maintaining intra-application contention-free routing and avoiding scalability issues. Using extensive evaluations, we show that both ARK and NRK significantly improve the communication runtime by up to 2.7x.