Rethinking DVFS for Mobile LLMs: Unified Energy-Aware Scheduling with CORE

Despite the rapid adoption of large language models (LLMs) in mobile applications, deploying them efficiently on resource-constrained devices remains challenging due to limited compute, memory, and energy constraints. In this paper, we first evaluate the energy efficiency of state-of-the-art mobile LLM frameworks across multiple models and uncover a key inefficiency: the default governors make independent decisions which can result in 23.0–40.4% longer latency or 5.0–16.6% higher energy use compared to optimal frequency combinations. We then conduct an in-depth analysis to reveal the root cause–the lack of cross-resource coordination of these governors during prefilling and decoding. Building on these findings, we present CORE, a unified, energy-aware governor that jointly coordinates CPU, GPU, and memory frequencies for mobile LLM inference. Experiments across diverse LLMs show that CORE reduces time-to-first-token by 8.5-17.7% and time-per-token by 27.8-39.6% on average, without increasing energy per token.