Energy-efficient variable-flow liquid cooling in 3D stacked architectures

Abstract

Abstract-Liquid cooling has emerged as a promising solution for addressing the elevated temperatures in 3D stacked architectures. In this work, we first propose a framework for detailed thermal modeling of the microchannels embedded between the tiers of the 3D system. In multicore systems, workload varies at runtime, and the system is generally not fully utilized. Thus, it is not energy-efficient to adjust the coolant flow rate based on the worst-case conditions, as this would cause an excess in pump power. For energy-efficient cooling, we propose a novel controller to adjust the liquid flow rate to meet the desired temperature and to minimize pump energy consumption. Our technique also includes a job scheduler, which balances the temperature across the system to maximize cooling efficiency and to improve reliability. Our method guarantees operating below the target temperature while reducing the cooling energy by up to 30%, and the overall energy by up to 12% in comparison to using the highest coolant flow rate.

Power-Thermal Modeling and Control of Energy-Efficient Servers and Datacenters

“…The dies are of size 1 cm × 1.1 cm and the heat flux densities range from 8 to 64 W/cm 2 in the two dies. Further details about the floorplan and power dissipations can be found in pervious works [77,96,112]. In this experiment, the worst-case (peak) power dissipation of the 3D-MPSoC functional elements [77,96,112] (obtained using measurements) are used in the optimization process.…”

“…Thermal management methods for 3D MPSoCs using a variable-flow liquid cooling have been recently proposed [77]. These policies use experimentally-driven sets of rules to control the temperature profile of the 3D MPSoC while ensuring performance requirements to be satisfied.…”

“…Fig. 14 Peak and average temperatures observed using all the policies, both for the average case across all workloads and maximum workload on four-tier 3D MPSoC [94] • LUT-based flow rate control with LB (LC_VAR) [77]: It dynamically changes the flow rate based on the predicted maximum temperature, while the jobs are scheduled with LB.…”

“…c) Thermal Package Control Knobs The knobs at the thermal package level are responsible of changing the cooling capabilities, which is related to the injected fluid in the case of 3D MPSoCs with liquid cooling. For instance, the volumetric flow rate of the injected fluid can be varied by changing either the liquid pumping power [77], or varying the value of a flow-control valve [78].…”

ICCAD 2015 contest in 3D interlayer cooling optimized network

“…There have also been methods proposed to address efficient run-time operation of liquid-cooled microchannels [5]. However, these methods do not take advantage of the nearly endless possibilities of designing microfluidic networks using the existing CMOS process with no additional manufacturing cost.…”