- A. Jha, Dirk Groeneveld, Emma Strubell, Iz Beltagy. 2023. How To Train Your (Compressed) Large Language Model. Abstract: With the increase in the size of large language models (LLMs), we need compression methods that can reduce the model size while preserving the generality and zero-shot promptability of the model. This goal is more ambitious than the typical compression setup, which reduces the model's size at the expense of specializing it to a specific end-task. To study this, we develop a task-agnostic compression pipeline with a large-scale evaluation comprising language modeling perplexity and 12 zero-shot end-tasks. Our results show that a simple layer-wise pruning followed by continued language model pretraining matches or outperforms three existing state-of-the-art baselines while being 1.5x more computationally efficient. However, unlike typical task-specialized compression, our best-compressed model significantly underperforms a similar-sized model trained from scratch. We posit the half-sized pretrained model as an upper bound for task-agnostic compression and call for future work to bridge this gap under a reasonable token budget. Our findings highlight the inadequacy of existing compression methods for LLMs and establish a requirement for new methods that preserve a model's generality and zero-shot promptability under compression. We release our code and evaluation setup to facilitate reproducibility and help iterate on method design.
