Optimal Expert-Attention Allocation in Mixture-of-Experts: A Scalable Law for Dynamic Model Design

Junzhuo Li, Peijie Jiang, Changxin Tian, Jia Liu, Zhiqiang Zhang, Xuming Hu


Abstract
This paper presents a novel extension of neural scaling laws to Mixture-of-Experts (MoE) models, focusing on the optimal allocation of compute between expert and attention sub-layers. As MoE architectures have emerged as an efficient method for scaling model capacity without proportionally increasing computation, determining the optimal expert-attention compute ratio becomes critical. We define the ratio r as the fraction of total FLOPs per token dedicated to the expert layers versus the attention layers, and explore how this ratio interacts with the overall compute budget and model sparsity. Through extensive experiments with GPT-style MoE Transformers, we empirically find that the optimal ratio r\* follows a power-law relationship with total compute and varies with sparsity. Our analysis leads to an explicit formula for r\*, enabling precise control over the expert-attention compute allocation. We generalize the Chinchilla scaling law by incorporating this architectural parameter, providing a new framework for tuning MoE models beyond size and data. Our findings offer practical guidelines for designing efficient MoE models, optimizing performance while respecting fixed compute budgets.
Anthology ID:
2026.acl-industry.98
Volume:
Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (ACL 2026)
Month:
July
Year:
2026
Address:
San Diego, California, USA
Editors:
Yunyao Li, Georg Rehm, Mei Tu
Venue:
ACL
SIG:
Publisher:
Association for Computational Linguistics
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Pages:
1406–1418
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URL:
https://preview.aclanthology.org/ingest-acl/2026.acl-industry.98/
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Bibkey:
Cite (ACL):
Junzhuo Li, Peijie Jiang, Changxin Tian, Jia Liu, Zhiqiang Zhang, and Xuming Hu. 2026. Optimal Expert-Attention Allocation in Mixture-of-Experts: A Scalable Law for Dynamic Model Design. In Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (ACL 2026), pages 1406–1418, San Diego, California, USA. Association for Computational Linguistics.
Cite (Informal):
Optimal Expert-Attention Allocation in Mixture-of-Experts: A Scalable Law for Dynamic Model Design (Li et al., ACL 2026)
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https://preview.aclanthology.org/ingest-acl/2026.acl-industry.98.pdf