BYOM: Building Your Own Multi-Task Model For Free
Weisen Jiang, Baijiong Lin, Han Shi, Yu Zhang, Zhenguo Li, James T. Kwok
TL;DR
BYOM tackles the challenge of building a high-performance multi-task system from many task-specific finetuned checkpoints without access to task data. It introduces two parameter-efficient merging strategies: BYOM-FFT, which injects task knowledge as sparse vectors from fully finetuned models, and BYOM-LoRA, which compresses LoRA factors using a rank-$q$ SVD-based approximation. Across CV and NLP benchmarks, BYOM-FFT and BYOM-LoRA consistently outperform existing merging methods and approach Single-Task performance while using far fewer parameters, with BYOM-FFT also serving as a general add-on to boost other mergers. This data-free, computation-efficient approach broadens practical deployment of multi-task systems and suggests directions for integrating task knowledge into shared backbones.
Abstract
Recently, various merging methods have been proposed to build a multi-task model from task-specific finetuned models without retraining. However, existing methods suffer from a large performance deterioration compared to using multiple task-specific models. In this paper, we propose to inject task-specific knowledge into the merged model and design two parameter-efficient approaches (BYOM-FFT and BYOM-LoRA) to Build Your Own Multi-task model. BYOM-FFT is for merging fully finetuned models, while BYOM-LoRA is for LoRA-finetuned models. Both methods are data-free and computation-efficient. Extensive experiments on computer vision and natural language processing tasks show that the proposed BYOM methods outperform existing merging methods by a large margin. Moreover, BYOM-FFT is general and can be integrated into existing merging methods to further boost performance.
