From Bottom to Top: Extending the Potential of Parameter Efficient Fine-Tuning

Jihao Gu, Zelin Wang, Yibo Zhang, Ziji Zhang, Ping Gong


Abstract
With the proliferation of large language models, Parameter Efficient Fine-Tuning (PEFT) method, which freeze pre-trained parameters and only fine-tune a few task-specific parameters, are playing an increasingly important role. However, previous work primarily applied uniform operations across all layers of the model, overlooking the fact that different layers in a transformer store different information. In the process of exploration, We find that there is a significant differences in fine-tuning strategies between different layers, and fine-tuning only a subset of layers can even achieve comparable performance. Based on this, we propose the Hybrid LoRA-Prefix Tuning(HLPT) method, which uses enhanced LoRA and Prefix-tuning methods with learnable adaptive mechanism separately for the bottom and top layers, and the Half Hybrid LoRA-Prefix Tuning(H2LPT) method, which goes a step further, reducing the parameter count to nearly half by omitting fine-tuning in the middle layers. Extensive experiments with large language models on various downstream tasks provide strong evidence for the potential of PEFT focusing on different layers’ interactions and the effectiveness of our methods. Furthermore, we validate the robustness of these methods and their advantages in speeding up training convergence, reducing inference time requirements.
Anthology ID:
2024.emnlp-main.204
Volume:
Proceedings of the 2024 Conference on Empirical Methods in Natural Language Processing
Month:
November
Year:
2024
Address:
Miami, Florida, USA
Editors:
Yaser Al-Onaizan, Mohit Bansal, Yun-Nung Chen
Venue:
EMNLP
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
3488–3500
Language:
URL:
https://aclanthology.org/2024.emnlp-main.204
DOI:
Bibkey:
Cite (ACL):
Jihao Gu, Zelin Wang, Yibo Zhang, Ziji Zhang, and Ping Gong. 2024. From Bottom to Top: Extending the Potential of Parameter Efficient Fine-Tuning. In Proceedings of the 2024 Conference on Empirical Methods in Natural Language Processing, pages 3488–3500, Miami, Florida, USA. Association for Computational Linguistics.
Cite (Informal):
From Bottom to Top: Extending the Potential of Parameter Efficient Fine-Tuning (Gu et al., EMNLP 2024)
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PDF:
https://aclanthology.org/2024.emnlp-main.204.pdf