Not All Adapters Matter: Selective Adapter Freezing for Memory-Efficient Fine-Tuning of Language Models

Hyegang Son, Yonglak Son, Changhoon Kim, Young Geun Kim


Abstract
Transformer-based large-scale pre-trained models achieve great success. Fine-tuning is the standard practice for leveraging these models in downstream tasks. Among the fine-tuning methods, adapter-tuning provides a parameter-efficient fine-tuning by introducing lightweight trainable modules while keeping most pre-trained parameters frozen. However, existing adapter-tuning methods still impose substantial resource usage. Through our investigation, we show that each adapter unequally contributes to both task performance and resource usage. Motivated by this insight, we propose Selective Adapter FrEezing (SAFE), which gradually freezes less important adapters early to reduce unnecessary resource usage while maintaining performance. In our experiments, SAFE reduces memory usage, computation amount, and training time by 42.85%, 34.59%, and 11.82%, respectively, while achieving comparable or better task performance compared to the baseline. We also demonstrate that SAFE induces regularization effect, thereby smoothing the loss landscape, which enables the model to generalize better by avoiding sharp minima.
Anthology ID:
2025.naacl-long.480
Volume:
Proceedings of the 2025 Conference of the Nations of the Americas Chapter of the Association for Computational Linguistics: Human Language Technologies (Volume 1: Long Papers)
Month:
April
Year:
2025
Address:
Albuquerque, New Mexico
Editors:
Luis Chiruzzo, Alan Ritter, Lu Wang
Venue:
NAACL
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
9479–9496
Language:
URL:
https://preview.aclanthology.org/Ingest-2025-COMPUTEL/2025.naacl-long.480/
DOI:
Bibkey:
Cite (ACL):
Hyegang Son, Yonglak Son, Changhoon Kim, and Young Geun Kim. 2025. Not All Adapters Matter: Selective Adapter Freezing for Memory-Efficient Fine-Tuning of Language Models. In Proceedings of the 2025 Conference of the Nations of the Americas Chapter of the Association for Computational Linguistics: Human Language Technologies (Volume 1: Long Papers), pages 9479–9496, Albuquerque, New Mexico. Association for Computational Linguistics.
Cite (Informal):
Not All Adapters Matter: Selective Adapter Freezing for Memory-Efficient Fine-Tuning of Language Models (Son et al., NAACL 2025)
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PDF:
https://preview.aclanthology.org/Ingest-2025-COMPUTEL/2025.naacl-long.480.pdf