A combined sensor placement and convex optimization approach for thermal management in 3D-MPSoC with liquid cooling

Modern high-performance processors employ thermal management systems, which rely on accurate readings of on-die thermal sensors. Systematic tools for analysis and determination of best allocation and placement of thermal sensors is therefore a highly relevant problem. Moreover liquid cooling has emerged as a promising solution for addressing the elevated temperatures in 3D Multi-Processor Systems-on-Chips (MPSoCs). In this work, we present a combined sensor placement and convex optimization approach for thermal management in 3D-MPSoC with liquid cooling. This approach first finds the best locations inside the 3D-MPSoC where thermal sensors can be placed using a greedy approach. Then, the temperature sensing information is subsequently used by our convex-based thermal management policy to optimize the performance of the MPSoC while guaranteeing a reliable working condition. We perform experiments on a 3D multicore architecture case-study using benchmarks ranging from web-accessing to playing multimedia. Our results show a reduction up to 10 in the number of required sensors. Moreover our policy satisfies performance requirements, while reducing cooling energy by up to 72% compared with traditional state of the art liquid cooling techniques. The proposed policy also keeps the thermal profile up to 18 1C lower compared with state of the art 3D thermal management techniques using variable-flow liquid cooling. & 2011 Elsevier B.V. All rights reserved.