Thermal and Voltage-Aware Performance Management of 3-D MPSoCs With Flow Cell Arrays and Integrated SC Converters

Flow cell arrays (FCAs) concurrently provide efficient on-chip liquid cooling and electrochemical power generation. This technology is especially promising for 3-D multiprocessor systems-on-chip (3-D MPSoCs) realized in deeply scaled technologies, which present very challenging power and thermal requirements. Indeed, FCAs effectively improve power delivery network (PDN) performance, particularly if switched capacitor (SC) converters are employed to decouple the flow cells and the systems-on-chip voltages, allowing each to operate at their optimal point. Nonetheless, the design of FCA-based solutions entails nonobvious considerations and tradeoffs, stemming from their dual role in governing both the thermal and power delivery characteristics of 3-D MPSoCs. Showcasing them in this article, we explore multiple FCA design configurations and demonstrate that this technology can decrease the temperature of a heterogeneous 3-D MPSoC by 78 °C, and its total power consumption by 46%, compared to a high-performance cold-plate-based liquid cooling solution. At the same time, FCAs enable up to 90% voltage drop recovery across dies, using SC converters occupying a small fraction of the chip area. Such outcomes provide an opportunity to boost 3-D MPSoC computing performance by increasing the operating frequency of dies. Leveraging these results, we introduce a novel temperature and voltage-aware model-predictive control (MPC) strategy that optimizes power efficiency during runtime. We achieve application-wide speedups of up to 16% on various machine learning (ML), data mining, and other high-performance benchmarks while keeping the 3-D MPSoC temperature below 83 °C and voltage drops below 5%.