Open, Small, Rigmarole -- Evaluating Llama 3.2 3B's Feedback for Programming Exercises

Large Language Models (LLMs) have been subject to extensive research in the past few years. This is particularly true for the potential of LLMs to generate formative programming feedback for novice learners at university. In contrast to Generative AI (GenAI) tools based on LLMs, such as GPT, smaller and open models have received much less attention. Yet, they offer several benefits, as educators can let them run on a virtual machine or personal computer. This can help circumvent some major concerns applicable to other GenAI tools and LLMs (e. g., data protection, lack of control over changes, privacy). Therefore, this study explores the feedback characteristics of the open, lightweight LLM Llama 3.2 (3B). In particular, we investigate the models' responses to authentic student solutions to introductory programming exercises written in Java. The generated output is qualitatively analyzed to help evaluate the feedback's quality, content, structure, and other features. The results provide a comprehensive overview of the feedback capabilities and serious shortcomings of this open, small LLM. We further discuss the findings in the context of previous research on LLMs and contribute to benchmarking recently available GenAI tools and their feedback for novice learners of programming. Thereby, this work has implications for educators, learners, and tool developers attempting to utilize all variants of LLMs (including open, and small models) to generate formative feedback and support learning.