GeoMesh: Workload-Balanced and Sign-Compressed Geo-Distributed LLM Training

Changyong Shin, Jaerim Park, Minchul Kang, Younghun Go, Zhixiong Niu, Yongqiang Xiong, Gyeongsik Yang, Chuck Yoo


Abstract
Large language models are increasingly trained on GPUs distributed across multiple regions, but geo-distributed training is challenging in practice. Real clusters often contain GPUs with different speeds and memory capacities, and they communicate over slow wide-area networks. Our analysis shows that this creates serious problems: existing synchronous methods preserve stable updates, but fast GPUs wait up to 20.9% of their runtime for slower ones, and all workers spend, on average, 65.8% of their runtime on synchronization. Recent asynchronous methods reduce waiting time but worsen the model accuracy due to stale updates. To address the problems, we present GeoMesh, a synchronous geo-distributed training framework for heterogeneous GPUs. GeoMesh balances per-worker workloads by assigning each GPU a suitable batch size and number of inner steps, so faster GPUs do more useful work instead of waiting. It also reduces communication volume by nearly 32× by exchanging compressed sign-based pseudo-gradients with lightweight magnitude and token count. Across heterogeneous GPUs and Azure-derived WAN, GeoMesh reduces time-to-target perplexity by up to 70.2% over representative baselines and lowers straggler- and WAN-induced GPU idle by up to 8.0× and 5.6×, respectively, while preserving comparable zero-shot accuracy.
Anthology ID:
2026.findings-emnlp.720
Volume:
Findings of the Association for Computational Linguistics: EMNLP 2026
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
Findings
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
15131–15152
Language:
URL:
https://aclanthology.org/2026.findings-emnlp.720/
DOI:
Bibkey:
Cite (ACL):
Changyong Shin, Jaerim Park, Minchul Kang, Younghun Go, Zhixiong Niu, Yongqiang Xiong, Gyeongsik Yang, and Chuck Yoo. 2026. GeoMesh: Workload-Balanced and Sign-Compressed Geo-Distributed LLM Training. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 15131–15152, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
GeoMesh: Workload-Balanced and Sign-Compressed Geo-Distributed LLM Training (Shin et al., Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-emnlp.720.pdf