Exploring Parameter-Efficient Fine-Tuning Techniques for Code Generation with Large Language Models

Large Language Models (LLMs) demonstrate impressive capabilities to generate accurate code snippets given natural language intents in zero-shot, i.e., without the need for specific fine-tuning. While prior studies have highlighted the advantages of fine-tuning LLMs, this process incurs high computational costs, making it impractical in resource-scarce environments, particularly for models with billions of parameters. To address these challenges, previous research explored In-Context Learning (ICL) as a strategy to guide the LLM generative process with task-specific prompt examples. However, ICL introduces inconveniences, such as the need for designing contextually relevant prompts and the absence of learning task-specific parameters, thereby limiting downstream task performance. In this context, we foresee Parameter-Efficient Fine-Tuning (PEFT) techniques as a promising approach to efficiently specialize LLMs to task-specific data while maintaining reasonable resource consumption. In this paper, we deliver a comprehensive study of PEFT techniques for LLMs under the automated code generation scenario. Our comprehensive investigation of PEFT techniques for LLMs reveals their superiority and potential over ICL across a diverse set of LLMs. Additionally, we demonstrate the extended capabilities of PEFT, showcasing its ability to learn from two distinct datasets jointly without compromising performance. Furthermore, our study highlights the potential for tuning larger LLMs and significant reductions in memory usage by combining PEFT with quantization. Therefore, this study opens opportunities for broader applications of PEFT in software engineering scenarios. Our code is available at https://github.com/martin-wey/peft-llm-code/.