LightMoE: Reducing Mixture-of-Experts Redundancy through Expert Replacing

Fuente: arXiv
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Autori principali: Hao, Jiawei, Hao, Zhiwei, Guo, Jianyuan, Shen, Li, Luo, Yong, Hu, Han, Zeng, Dan
Natura: Preprint
Pubblicazione: 2026
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author Hao, Jiawei
Hao, Zhiwei
Guo, Jianyuan
Shen, Li
Luo, Yong
Hu, Han
Zeng, Dan
author_facet Hao, Jiawei
Hao, Zhiwei
Guo, Jianyuan
Shen, Li
Luo, Yong
Hu, Han
Zeng, Dan
contents Mixture-of-Experts (MoE) based Large Language Models (LLMs) have demonstrated impressive performance and computational efficiency. However, their deployment is often constrained by substantial memory demands, primarily due to the need to load numerous expert modules. While existing expert compression techniques like pruning or merging attempt to mitigate this, they often suffer from irreversible knowledge loss or high training overhead. In this paper, we propose a novel expert compression paradigm termed expert replacing, which replaces redundant experts with parameter-efficient modules and recovers their capabilities with low training costs. We find that even a straightforward baseline of this paradigm yields promising performance. Building on this foundation, we introduce LightMoE, a framework that enhances the paradigm by introducing adaptive expert selection, hierarchical expert construction, and an annealed recovery strategy. Experimental results show that LightMoE matches the performance of LoRA fine-tuning at a 30% compression ratio. Even under a more aggressive 50% compression rate, it outperforms existing methods and achieves average performance improvements of 5.6% across five diverse tasks. These findings demonstrate that LightMoE strikes a superior balance among memory efficiency, training efficiency, and model performance.
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id arxiv_https___arxiv_org_abs_2603_12645
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle LightMoE: Reducing Mixture-of-Experts Redundancy through Expert Replacing
Hao, Jiawei
Hao, Zhiwei
Guo, Jianyuan
Shen, Li
Luo, Yong
Hu, Han
Zeng, Dan
Machine Learning
Artificial Intelligence
Mixture-of-Experts (MoE) based Large Language Models (LLMs) have demonstrated impressive performance and computational efficiency. However, their deployment is often constrained by substantial memory demands, primarily due to the need to load numerous expert modules. While existing expert compression techniques like pruning or merging attempt to mitigate this, they often suffer from irreversible knowledge loss or high training overhead. In this paper, we propose a novel expert compression paradigm termed expert replacing, which replaces redundant experts with parameter-efficient modules and recovers their capabilities with low training costs. We find that even a straightforward baseline of this paradigm yields promising performance. Building on this foundation, we introduce LightMoE, a framework that enhances the paradigm by introducing adaptive expert selection, hierarchical expert construction, and an annealed recovery strategy. Experimental results show that LightMoE matches the performance of LoRA fine-tuning at a 30% compression ratio. Even under a more aggressive 50% compression rate, it outperforms existing methods and achieves average performance improvements of 5.6% across five diverse tasks. These findings demonstrate that LightMoE strikes a superior balance among memory efficiency, training efficiency, and model performance.
title LightMoE: Reducing Mixture-of-Experts Redundancy through Expert Replacing
topic Machine Learning
Artificial Intelligence
url https://arxiv.org/abs/2603.12645