Using Multiple Paths in NoCs for Guaranteed Resource Allocation and Improved Best Effort Performance in NoCs.

Networks-on-Chips (NoCs) provide communication platforms to Systems-on-Chips (SoCs). In NoCs, channels are generally shared between traffic flows, resulting in contention. However, certain flows require delivery guarantees. Differentiated quality-of-service (QoS) is achieved by providing guaranteed services such as guaranteed throughput (GT) to certain flows, on top of the regular best-effort (BE) delivery. Most current design methodologies employ a single-path mapping for each traffic flow. Such resource allocation is suboptimal for GT traffic and severely degrades performance of BE traffic. To solve this problem, we propose spatially distributing traffic and its guarantees in several paths per flow, while keeping the BE routing simple. Our experiments on a mesh in a transaction level simulator indicate that improvements of 20-48% in latency and 6-20% in throughput of BE traffic are achievable. We argue that this gain can be achieved cheaply with simple modifications to current methodologies.