ReaLB: Real-Time Load Balancing for Multimodal MoE Inference

Fuente: arXiv
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Hauptverfasser: Wang, Yingping, Wu, Yi, Wu, Xiangyu, Cui, Junwei, Cai, Weilin, Guo, Zhijiang, Huang, Jiayi
Format: Preprint
Veröffentlicht: 2026
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author Wang, Yingping
Wu, Yi
Wu, Xiangyu
Cui, Junwei
Cai, Weilin
Guo, Zhijiang
Huang, Jiayi
author_facet Wang, Yingping
Wu, Yi
Wu, Xiangyu
Cui, Junwei
Cai, Weilin
Guo, Zhijiang
Huang, Jiayi
contents Mixture-of-Experts (MoE) architectures are widely used in modern large language models and multimodal models. However, inference efficiency is often limited by highly dynamic and skewed expert workloads across different modalities. During the prefill stage with large batch sizes, vision tokens frequently dominate the input sequences. Under expert parallelism (EP), this leads to severe load imbalance, where a subset of devices becomes overloaded, reducing overall system throughput. We propose ReaLB, a real-time load balancing method for multimodal MoE (MMoE) inference that introduces zero scheduling overhead. ReaLB dynamically adjusts the computation precision of MoE experts at runtime on a per-EP-rank basis. For ranks dominated by vision-heavy experts, ReaLB assigns lower-precision computation to improve execution efficiency by exploiting FP4 Tensor Cores. ReaLB does not require redundant experts or additional memory allocation. Instead, it performs layer-wise expert precision transformation on the fly and hides the associated overhead within the dispatch phase before MoE computation. Experiments on representative MMoE models show that ReaLB achieves 1.10$\times$-1.32$\times$ end-to-end speedup while limiting average accuracy degradation to within 1%.
format Preprint
id arxiv_https___arxiv_org_abs_2604_19503
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle ReaLB: Real-Time Load Balancing for Multimodal MoE Inference
Wang, Yingping
Wu, Yi
Wu, Xiangyu
Cui, Junwei
Cai, Weilin
Guo, Zhijiang
Huang, Jiayi
Distributed, Parallel, and Cluster Computing
Mixture-of-Experts (MoE) architectures are widely used in modern large language models and multimodal models. However, inference efficiency is often limited by highly dynamic and skewed expert workloads across different modalities. During the prefill stage with large batch sizes, vision tokens frequently dominate the input sequences. Under expert parallelism (EP), this leads to severe load imbalance, where a subset of devices becomes overloaded, reducing overall system throughput. We propose ReaLB, a real-time load balancing method for multimodal MoE (MMoE) inference that introduces zero scheduling overhead. ReaLB dynamically adjusts the computation precision of MoE experts at runtime on a per-EP-rank basis. For ranks dominated by vision-heavy experts, ReaLB assigns lower-precision computation to improve execution efficiency by exploiting FP4 Tensor Cores. ReaLB does not require redundant experts or additional memory allocation. Instead, it performs layer-wise expert precision transformation on the fly and hides the associated overhead within the dispatch phase before MoE computation. Experiments on representative MMoE models show that ReaLB achieves 1.10$\times$-1.32$\times$ end-to-end speedup while limiting average accuracy degradation to within 1%.
title ReaLB: Real-Time Load Balancing for Multimodal MoE Inference
topic Distributed, Parallel, and Cluster Computing
url https://arxiv.org/abs/2604.19503