Harmony in Divergence: Towards Fast, Accurate, and Memory-efficient Zeroth-order LLM Fine-tuning

Fuente: arXiv
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Main Authors: Tan, Qitao, Liu, Jun, Zhan, Zheng, Ding, Caiwei, Wang, Yanzhi, Ma, Xiaolong, Lee, Jaewoo, Lu, Jin, Yuan, Geng
Format: Preprint
Published: 2025
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author Tan, Qitao
Liu, Jun
Zhan, Zheng
Ding, Caiwei
Wang, Yanzhi
Ma, Xiaolong
Lee, Jaewoo
Lu, Jin
Yuan, Geng
author_facet Tan, Qitao
Liu, Jun
Zhan, Zheng
Ding, Caiwei
Wang, Yanzhi
Ma, Xiaolong
Lee, Jaewoo
Lu, Jin
Yuan, Geng
contents Large language models (LLMs) excel across various tasks, but standard first-order (FO) fine-tuning demands considerable memory, significantly limiting real-world deployment. Recently, zeroth-order (ZO) optimization stood out as a promising memory-efficient training paradigm, avoiding backward passes and relying solely on forward passes for gradient estimation, making it attractive for resource-constrained scenarios. However, ZO method lags far behind FO method in both convergence speed and accuracy. To bridge the gap, we introduce a novel layer-wise divergence analysis that uncovers the distinct update pattern of FO and ZO optimization. Aiming to resemble the learning capacity of FO method from the findings, we propose Divergence-driven Zeroth-Order (DiZO) optimization. DiZO conducts divergence-driven layer adaptation by incorporating projections to ZO updates, generating diverse-magnitude updates precisely scaled to layer-wise individual optimization needs. Our results demonstrate that DiZO significantly reduces the needed iterations for convergence without sacrificing throughput, cutting training GPU hours by up to 48\% on various datasets. Moreover, DiZO consistently outperforms the representative ZO baselines in fine-tuning RoBERTa-large, OPT-series, and Llama-series on downstream tasks and, in some cases, even surpasses memory-intensive FO fine-tuning. Our code is released at https://github.com/Skilteee/DiZO.
format Preprint
id arxiv_https___arxiv_org_abs_2502_03304
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Harmony in Divergence: Towards Fast, Accurate, and Memory-efficient Zeroth-order LLM Fine-tuning
Tan, Qitao
Liu, Jun
Zhan, Zheng
Ding, Caiwei
Wang, Yanzhi
Ma, Xiaolong
Lee, Jaewoo
Lu, Jin
Yuan, Geng
Machine Learning
Artificial Intelligence
Computation and Language
Large language models (LLMs) excel across various tasks, but standard first-order (FO) fine-tuning demands considerable memory, significantly limiting real-world deployment. Recently, zeroth-order (ZO) optimization stood out as a promising memory-efficient training paradigm, avoiding backward passes and relying solely on forward passes for gradient estimation, making it attractive for resource-constrained scenarios. However, ZO method lags far behind FO method in both convergence speed and accuracy. To bridge the gap, we introduce a novel layer-wise divergence analysis that uncovers the distinct update pattern of FO and ZO optimization. Aiming to resemble the learning capacity of FO method from the findings, we propose Divergence-driven Zeroth-Order (DiZO) optimization. DiZO conducts divergence-driven layer adaptation by incorporating projections to ZO updates, generating diverse-magnitude updates precisely scaled to layer-wise individual optimization needs. Our results demonstrate that DiZO significantly reduces the needed iterations for convergence without sacrificing throughput, cutting training GPU hours by up to 48\% on various datasets. Moreover, DiZO consistently outperforms the representative ZO baselines in fine-tuning RoBERTa-large, OPT-series, and Llama-series on downstream tasks and, in some cases, even surpasses memory-intensive FO fine-tuning. Our code is released at https://github.com/Skilteee/DiZO.
title Harmony in Divergence: Towards Fast, Accurate, and Memory-efficient Zeroth-order LLM Fine-tuning
topic Machine Learning
Artificial Intelligence
Computation and Language
url https://arxiv.org/abs/2502.03304