Direct-On-Chip Hotspot Targeted Microjet Cooling for Ultra-fast Inference at Scale Running on Groq Language Processing Unit (LPU)

This paper investigates the thermal management strategies targeted at hotspot mitigation based on the Groq Language Processing Unit (LPU™) architecture with functionally sliced power map. To address this challenge, this study explores the concept of direct-on-chip hotspots targeted microjet cooling corresponding to the power map through the entire LPU™ chip. The customized heat transfer coefficient map can be achieved by tailoring the inlet nozzle diameter and pitch, as well as the flow conditions to match the hotspots within the chip, or high-power densities. Based on the modeling results, this direct-on-chip microjet cooling can successfully address the potential temperature non-uniformity from different functional blocks within the logic die. It achieves a temperature nonuniformity within 4 ℃ across the logic die and significantly reduces the thermal coupling between LPU™ and the nearby chiplet in an exploratory use case scenario setting.