Beyond End-to-End: Dynamic Chain Optimization for Private LLM Adaptation on the Edge

Yebo Wu, Jingguang Li, Chunlin Tian, KaHou Tam, Zhijiang Guo, Li Li


Abstract
Federated fine-tuning enables privacy-preserving LLM adaptation but faces a critical bottleneck: the disparity between LLMs’ high memory demands and edge devices’ limited capacity. To break the memory barrier, we propose Chain Federated Fine-tuning (ChainFed), an innovative paradigm that forgoes end-to-end updates in favor of a sequential, layer-by-layer manner. It first trains the initial adapter to convergence, freezes its weights, and then proceeds to the next. This iterative train-and-freeze process forms an optimization chain, gradually enhancing the model’s task-specific proficiency. ChainFed further integrates three core techniques: 1) Dynamic Layer Co-Tuning to bridge semantic gaps between sequentially tuned layers and facilitate information flow; 2) Globally Perceptive Optimization to endow each adapter with foresight beyond its local objective; 3) Function-Oriented Adaptive Tuning to automatically identify the optimal fine-tuning starting point. Extensive experiments on multiple benchmarks demonstrate the superiority of ChainFed over existing methods, boosting average accuracy by up to 46.46%.
Anthology ID:
2026.acl-long.839
Volume:
Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Month:
July
Year:
2026
Address:
San Diego, California, United States
Editors:
Maria Liakata, Viviane P. Moreira, Jiajun Zhang, David Jurgens
Venue:
ACL
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Publisher:
Association for Computational Linguistics
Note:
Pages:
18419–18435
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URL:
https://preview.aclanthology.org/ingest-acl/2026.acl-long.839/
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Cite (ACL):
Yebo Wu, Jingguang Li, Chunlin Tian, KaHou Tam, Zhijiang Guo, and Li Li. 2026. Beyond End-to-End: Dynamic Chain Optimization for Private LLM Adaptation on the Edge. In Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers), pages 18419–18435, San Diego, California, United States. Association for Computational Linguistics.
Cite (Informal):
Beyond End-to-End: Dynamic Chain Optimization for Private LLM Adaptation on the Edge (Wu et al., ACL 2026)
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https://preview.aclanthology.org/ingest-acl/2026.acl-long.839.pdf
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