DPI: Exploiting Parameter Heterogeneity for Interference-Free Fine-Tuning

Fuente: arXiv
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Auteurs principaux: Liu, Xiaoyu, Guan, Xiaoyu, Liang, Di, Wu, Xianjie
Format: Preprint
Publié: 2026
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author Liu, Xiaoyu
Guan, Xiaoyu
Liang, Di
Wu, Xianjie
author_facet Liu, Xiaoyu
Guan, Xiaoyu
Liang, Di
Wu, Xianjie
contents Supervised fine-tuning (SFT) is a crucial step for adapting large language models (LLMs) to downstream tasks. However, conflicting objectives across heterogeneous SFT tasks often induce the "seesaw effect": optimizing for one task may degrade performance on others, particularly when model parameters are updated indiscriminately. In this paper, we propose a principled approach to disentangle and isolate task-specific parameter regions, motivated by the hypothesis that parameter heterogeneity underlies cross-task interference. Specifically, we first independently fine-tune LLMs on diverse SFT tasks and identify each task's core parameter region as the subset of parameters exhibiting the largest updates. Tasks with highly overlapping core parameter regions are merged for joint training, while disjoint tasks are organized into different stages. During multi-stage SFT, core parameters acquired in prior tasks are frozen, thereby preventing overwriting by subsequent tasks. To verify the effectiveness of our method, we conducted intensive experiments on multiple public datasets. The results showed that our dynamic parameter isolation strategy consistently reduced data conflicts and achieved consistent performance improvements compared to multi-stage and multi-task tuning baselines.
format Preprint
id arxiv_https___arxiv_org_abs_2601_17777
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle DPI: Exploiting Parameter Heterogeneity for Interference-Free Fine-Tuning
Liu, Xiaoyu
Guan, Xiaoyu
Liang, Di
Wu, Xianjie
Computation and Language
Artificial Intelligence
Supervised fine-tuning (SFT) is a crucial step for adapting large language models (LLMs) to downstream tasks. However, conflicting objectives across heterogeneous SFT tasks often induce the "seesaw effect": optimizing for one task may degrade performance on others, particularly when model parameters are updated indiscriminately. In this paper, we propose a principled approach to disentangle and isolate task-specific parameter regions, motivated by the hypothesis that parameter heterogeneity underlies cross-task interference. Specifically, we first independently fine-tune LLMs on diverse SFT tasks and identify each task's core parameter region as the subset of parameters exhibiting the largest updates. Tasks with highly overlapping core parameter regions are merged for joint training, while disjoint tasks are organized into different stages. During multi-stage SFT, core parameters acquired in prior tasks are frozen, thereby preventing overwriting by subsequent tasks. To verify the effectiveness of our method, we conducted intensive experiments on multiple public datasets. The results showed that our dynamic parameter isolation strategy consistently reduced data conflicts and achieved consistent performance improvements compared to multi-stage and multi-task tuning baselines.
title DPI: Exploiting Parameter Heterogeneity for Interference-Free Fine-Tuning
topic Computation and Language
Artificial Intelligence
url https://arxiv.org/abs/2601.17777