GreenCool: An Energy-Ecient Liquid Cooling Design Technique for 3D MPSoCs Via Channel Width Modulation

Mohamed Mostafa Sabry Aly, Arvind Sridhar, Jie Meng, Ayse Kivilcim Coskun, and David Atienza Alonso.
IEEE Transactions on Computer- Aided Design of Integrated Circuits and Systems, 31(12):1-14, 2012.
Liquid cooling using interlayer microchannels has appeared as a viable and scalable packaging technology for 3D multiprocessor system-on-chips (MPSoCs). Microchannelbased liquid cooling, however, can substantially increase the onchip thermal gradients, which are undesirable for reliability, performance, and cooling eciency. In this work we present GreenCool, an optimal design methodology for liquid-cooled 3D MPSoCs. GreenCool simultaneously minimizes the cooling energy for a given system while maintaining thermal gradients and peak temperatures under safe limits. This is accomplished by tuning the heat transfer characteristics of the microchannels using channel width modulation. Channel width modulation is compatible with the current process technologies and incurs minimal additional fabrication costs. Through an extensive set of experiments, we show that channel width modulation is capable of complementing and enhancing the benefits of temperature-aware floor-planning. We also experiment with a 6-core 3D system with stacked DRAM, for which GreenCool improves energy eciency by up to 53% compared to cooling optimization without channel modulation.