Routing on the Dependency Graph: A New Approach to Deadlock-Free High-Performance Routing

Abstract

Lossless interconnection networks are omnipresent in high performance computing systems, data centers and network-on-chip architectures. Such networks require efficient and deadlock-free routing functions to utilize the available hardware. Topology-aware routing functions become increasingly inapplicable, due to irregular topologies, which either are irregular by design or as a result of hardware failures. Existing topology-agnostic routing methods either suffer from poor load balancing or are not bounded in the number of virtual channels needed to resolve deadlocks in the routing tables. We propose a novel topology-agnostic routing approach which implicitly avoids deadlocks during the path calculation instead of solving both problems separately. We present a model implementation, called Nue, of a destination-based and oblivious routing function. Nue routing heuristically optimizes the load balancing while enforcing deadlock-freedom without exceeding a given number of virtual channels, which we demonstrate based on the InfiniBand architecture.