动态裁剪专家模块,让不同层用不同专家数,省参数又提速。
Adaptive and Fine-grained Module-wise Expert Pruning for Efficient LoRA-MoE Fine-Tuning

- 按模块动态裁剪低效专家,实现细粒度资源配置。
- 参数减少35%–43%,训练吞吐提升约10%,准确率不降反升。
- 适合追求高效微调的模型优化者,尤其大模型推理场景。
LoRA-MoE作为参数高效微调的有效范式,结合了LoRA的低成本与专家混合(MoE)的强适应能力。然而,现有框架对异构Transformer模块(如注意力查询/键投影和MLP门控网络)采用固定统一的专家配置,忽视其功能差异与容量需求,导致局部过度配置、冗余可训练参数及不必要的优化器状态开销。此外,以往方法全程强制专家负载均衡,虽在训练初期有益,但一旦路由模式稳定,该约束限制了专家对下游任务的专精发展。本文提出DMEP,一种基于动态模块级专家裁剪的新型LoRA-MoE微调框架。DMEP在训练中追踪专家利用率,按模块物理移除低效专家,形成更紧凑的专家结构。裁剪后模型继续训练,不再受负载均衡约束,使剩余专家专注下游任务并发展专精能力。通过联合调整模块级专家容量并消除冗余平衡,DMEP同时提升参数效率与训练效率。多组推理基准实验表明,DMEP将可训练参数减少35%–43%,训练吞吐提升约10%,且保持或超越均匀LoRA-MoE基线的下游推理精度。
原文摘要 · Abstract (English)
LoRA-MoE has emerged as an effective paradigm for parameter-efficient fine-tuning, combining the low training cost of LoRA with the increased adaptation capacity of Mixture-of-Experts (MoE). However, existing LoRA-MoE frameworks typically adopt a fixed and uniform expert configuration across heterogeneous Transformer modules (\eg, attention query/key projections and MLP gating networks), ignoring their distinct functional roles and capacity requirements. This design leads to localized over-provisioning, redundant trainable parameters, and unnecessary optimizer-state overhead. Moreover, prior methods enforce load balancing among experts throughout training. Although beneficial in the early stage, this constraint becomes restrictive once routing patterns stabilize, limiting expert specialization on downstream tasks. In this paper, we propose DMEP, a novel LoRA-MoE fine-tuning framework based on Dynamic Module-wise Expert Pruning. DMEP tracks expert utilization during training and physically removes low-utility experts on a per-module basis, yielding a more compact expert structure tailored to different modules. The pruned model then continues training without the load-balancing constraint, freeing the remaining experts to focus entirely on the downstream task and develop specialized expertise. By jointly adapting module-wise expert capacity and eliminating unnecessary balancing, DMEP improves both parameter efficiency and training efficiency. Extensive experiments on multiple reasoning benchmarks show that DMEP reduces trainable parameters by 35\%--43\% and improves training throughput by about 10\%, while maintaining or surpassing the downstream reasoning accuracy of uniform LoRA-MoE baselines.
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