Towards Greener Yet Powerful Code Generation via Quantization: An Empirical Study

ML-powered code generation aims to assist developers to write code in a more productive manner by intelligently generating code blocks based on natural language prompts. Recently, large pretrained deep learning models have pushed the boundary of code generation and achieved impressive performance.] However, the huge number of model parameters poses a significant challenge to their adoption in a typical software development environment, where a developer might use a standard laptop or mid-size server to develop code. Such large models cost significant resources in terms of memory, latency, dollars, as well as carbon footprint. Model compression is a promising approach to address these challenges. We have identified quantization as one of the most promising compression techniques for code-generation as it avoids expensive retraining costs. As quantization represents model parameters with lower-bit integer (e.g., int8), the model size and runtime latency would both benefit.] We empirically evaluate quantized models on code generation tasks across different dimensions: (i) resource usage and carbon footprint, (ii) accuracy, and (iii) robustness. Through systematic experiments we find a code-aware quantization recipe that could run even a 6-billion-parameter model in a regular laptop without significant accuracy or robustness degradation. We find that the recipe is readily applicable to code summarization task as well.