Thermal management in 3d networks-on-chip using dynamic link sharing.

3D integration is a practical solution for overcoming the problems of long and slow global wires in current and future generations of integrated circuits. This emerging technology stacks several die slices on top of each other in a single chip. It provides higher-bandwidth and lower-latency in the third dimension than a 2D design due to extremely shorter inter-layer distances. However, thermal challenges are a key impediment to stacking logic dies on top of each other. Particularly, routers in a 3D network-on-chip (NoC) are a main source of thermal hotspots, limiting the potential performance gains of the 3D integration. In this paper, we take advantage of the low-latency 3D vertical links to design a temperature-aware router architecture for 3D NoCs. This architecture reduces the peak temperature of routers, particularly routers that are farther from the heat sink, by balancing the traffic across all layers in a temperature-aware distributed way. This way, a router with high temperature can borrow the link and crossbar bandwidth of the routers in the layers closer to the heat sink to forward its packets, effectively offloading part of its traffic to them to reduce its temperature.