High performance, freedom from deadlocks, and freedom from livelocks are desirable properties of interconnection networks. Unfortunately, these can be conflicting goals because networks may either devote or under-utilize resources to avoid deadlocks and livelocks. These resources could otherwise be used to improve performance. For example, a minimal adaptive routing algorithm may forgo some routing options to ensure livelock-freedom but this hurts performance at high loads. In contrast, Chaotic routing achieves higher performance as it allows full-routing flexibility including misroutes (hops that take a packet farther from its destination) and it is deadlock-free. Unfortunately, Chaotic routing only provides probabilistic guarantees of livelock-freedom. In this paper we propose a new routing algorithm called BLAM (Bypass Buffers with Limited Adaptive lazy Misroutes) which achieves Chaos-like performance, but guarantees freedom from both deadlocks and livelocks. BLAM achieves Chaos-...
Mithuna Thottethodi, Alvin R. Lebeck, Shubhendu S.