Unveiling the Power of Multiple Gossip Steps: A Stability-Based Generalization Analysis in Decentralized Training

Fuente: arXiv
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Autori principali: Li, Qinglun, Liu, Yingqi, Zhang, Miao, Cao, Xiaochun, Yin, Quanjun, Shen, Li
Natura: Preprint
Pubblicazione: 2025
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author Li, Qinglun
Liu, Yingqi
Zhang, Miao
Cao, Xiaochun
Yin, Quanjun
Shen, Li
author_facet Li, Qinglun
Liu, Yingqi
Zhang, Miao
Cao, Xiaochun
Yin, Quanjun
Shen, Li
contents Decentralized training removes the centralized server, making it a communication-efficient approach that can significantly improve training efficiency, but it often suffers from degraded performance compared to centralized training. Multi-Gossip Steps (MGS) serve as a simple yet effective bridge between decentralized and centralized training, significantly reducing experiment performance gaps. However, the theoretical reasons for its effectiveness and whether this gap can be fully eliminated by MGS remain open questions. In this paper, we derive upper bounds on the generalization error and excess error of MGS using stability analysis, systematically answering these two key questions. 1). Optimization Error Reduction: MGS reduces the optimization error bound at an exponential rate, thereby exponentially tightening the generalization error bound and enabling convergence to better solutions. 2). Gap to Centralization: Even as MGS approaches infinity, a non-negligible gap in generalization error remains compared to centralized mini-batch SGD ($\mathcal{O}(T^{\frac{cβ}{cβ+1}}/{n m})$ in centralized and $\mathcal{O}(T^{\frac{2cβ}{2cβ+2}}/{n m^{\frac{1}{2cβ+2}}})$ in decentralized). Furthermore, we provide the first unified analysis of how factors like learning rate, data heterogeneity, node count, per-node sample size, and communication topology impact the generalization of MGS under non-convex settings without the bounded gradients assumption, filling a critical theoretical gap in decentralized training. Finally, promising experiments on CIFAR datasets support our theoretical findings.
format Preprint
id arxiv_https___arxiv_org_abs_2510_07980
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Unveiling the Power of Multiple Gossip Steps: A Stability-Based Generalization Analysis in Decentralized Training
Li, Qinglun
Liu, Yingqi
Zhang, Miao
Cao, Xiaochun
Yin, Quanjun
Shen, Li
Machine Learning
Artificial Intelligence
Numerical Analysis
Decentralized training removes the centralized server, making it a communication-efficient approach that can significantly improve training efficiency, but it often suffers from degraded performance compared to centralized training. Multi-Gossip Steps (MGS) serve as a simple yet effective bridge between decentralized and centralized training, significantly reducing experiment performance gaps. However, the theoretical reasons for its effectiveness and whether this gap can be fully eliminated by MGS remain open questions. In this paper, we derive upper bounds on the generalization error and excess error of MGS using stability analysis, systematically answering these two key questions. 1). Optimization Error Reduction: MGS reduces the optimization error bound at an exponential rate, thereby exponentially tightening the generalization error bound and enabling convergence to better solutions. 2). Gap to Centralization: Even as MGS approaches infinity, a non-negligible gap in generalization error remains compared to centralized mini-batch SGD ($\mathcal{O}(T^{\frac{cβ}{cβ+1}}/{n m})$ in centralized and $\mathcal{O}(T^{\frac{2cβ}{2cβ+2}}/{n m^{\frac{1}{2cβ+2}}})$ in decentralized). Furthermore, we provide the first unified analysis of how factors like learning rate, data heterogeneity, node count, per-node sample size, and communication topology impact the generalization of MGS under non-convex settings without the bounded gradients assumption, filling a critical theoretical gap in decentralized training. Finally, promising experiments on CIFAR datasets support our theoretical findings.
title Unveiling the Power of Multiple Gossip Steps: A Stability-Based Generalization Analysis in Decentralized Training
topic Machine Learning
Artificial Intelligence
Numerical Analysis
url https://arxiv.org/abs/2510.07980