  Large Language Models (LLMs) represent the recent success of deep learning in
achieving remarkable human-like predictive performance. It has become a
mainstream strategy to leverage fine-tuning to adapt LLMs for various
real-world applications due to the prohibitive expenses associated with LLM
training. The learning rate is one of the most important hyperparameters in LLM
fine-tuning with direct impacts on both fine-tuning efficiency and fine-tuned
LLM quality. Existing learning rate policies are primarily designed for
training traditional deep neural networks (DNNs), which may not work well for
LLM fine-tuning. We reassess the research challenges and opportunities of
learning rate tuning in the coming era of Large Language Models. This paper
makes three original contributions. First, we revisit existing learning rate
policies to analyze the critical challenges of learning rate tuning in the era
of LLMs. Second, we present LRBench++ to benchmark learning rate policies and
facilitate learning rate tuning for both traditional DNNs and LLMs. Third, our
experimental analysis with LRBench++ demonstrates the key differences between
LLM fine-tuning and traditional DNN training and validates our analysis.
