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Main Authors: Guo, Yihang, Yu, Tianyuan, Bai, Liang, Guo, Yanming, Ruan, Yirun, Li, William, Zheng, Weishi
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2509.23915
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author Guo, Yihang
Yu, Tianyuan
Bai, Liang
Guo, Yanming
Ruan, Yirun
Li, William
Zheng, Weishi
author_facet Guo, Yihang
Yu, Tianyuan
Bai, Liang
Guo, Yanming
Ruan, Yirun
Li, William
Zheng, Weishi
contents Multi-task learning (MTL) aims to build general-purpose vision systems by training a single network to perform multiple tasks jointly. While promising, its potential is often hindered by "unbalanced optimization", where task interference leads to subpar performance compared to single-task models. To facilitate research in MTL, this paper presents a systematic experimental analysis to dissect the factors contributing to this persistent problem. Our investigation confirms that the performance of existing optimization methods varies inconsistently across datasets, and advanced architectures still rely on costly grid-searched loss weights. Furthermore, we show that while powerful Vision Foundation Models (VFMs) provide strong initialization, they do not inherently resolve the optimization imbalance, and merely increasing data quantity offers limited benefits. A crucial finding emerges from our analysis: a strong correlation exists between the optimization imbalance and the norm of task-specific gradients. We demonstrate that this insight is directly applicable, showing that a straightforward strategy of scaling task losses according to their gradient norms can achieve performance comparable to that of an extensive and computationally expensive grid search. Our comprehensive analysis suggests that understanding and controlling gradient dynamics is a more direct path to stable MTL than developing increasingly complex methods.
format Preprint
id arxiv_https___arxiv_org_abs_2509_23915
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Revisit the Imbalance Optimization in Multi-task Learning: An Experimental Analysis
Guo, Yihang
Yu, Tianyuan
Bai, Liang
Guo, Yanming
Ruan, Yirun
Li, William
Zheng, Weishi
Computer Vision and Pattern Recognition
Multi-task learning (MTL) aims to build general-purpose vision systems by training a single network to perform multiple tasks jointly. While promising, its potential is often hindered by "unbalanced optimization", where task interference leads to subpar performance compared to single-task models. To facilitate research in MTL, this paper presents a systematic experimental analysis to dissect the factors contributing to this persistent problem. Our investigation confirms that the performance of existing optimization methods varies inconsistently across datasets, and advanced architectures still rely on costly grid-searched loss weights. Furthermore, we show that while powerful Vision Foundation Models (VFMs) provide strong initialization, they do not inherently resolve the optimization imbalance, and merely increasing data quantity offers limited benefits. A crucial finding emerges from our analysis: a strong correlation exists between the optimization imbalance and the norm of task-specific gradients. We demonstrate that this insight is directly applicable, showing that a straightforward strategy of scaling task losses according to their gradient norms can achieve performance comparable to that of an extensive and computationally expensive grid search. Our comprehensive analysis suggests that understanding and controlling gradient dynamics is a more direct path to stable MTL than developing increasingly complex methods.
title Revisit the Imbalance Optimization in Multi-task Learning: An Experimental Analysis
topic Computer Vision and Pattern Recognition
url https://arxiv.org/abs/2509.23915