ON–OFF: a reactive routing algorithm for dynamic thermal management in 3D NoCs

Abstract

Dynamic thermal management (DTM) techniques of three-dimensional (3D) Network-on-Chips (NoCs) are employed to rescue the chip from thermal difficulties. Reactive routing algorithms, which utilise router throttling technique as a popular DTM, disregard distribution of heat generation of routers resulting in more throttled routers as well as long packet delays in throttled processing elements. This study proposes a reactive routing algorithm for 3D NoCs to (i) dynamically detour packets from hot zones containing throttled routers and (ii) minimise the number of required router throttling in the network. The proposed routing algorithm defines two virtual networks to enhance the path diversity for packets in each layer of 3D NoCs. The selection of diverse paths distributes heat generation to alleviate the thermal variance. The proposed routing algorithm is analysed by turn model to achieve deadlock freedom. Access Noxim simulator is also used to evaluate the performance and the thermal behaviour of the proposed routing algorithm in the variety of conditions. Results show that the proposed routing algorithm improves temperature variance by 9-39% and reduces number of throttled routers by 16-86%, which is achieved at the cost of one extra virtual channel per each physical channel in the XY -plane.