AB-Training: A Communication-Efficient Approach for Distributed Low-Rank Learning
Daniel Coquelin, Katherina Flügel, Marie Weiel, Nicholas Kiefer, Muhammed Öz, Charlotte Debus, Achim Streit, Markus Götz
TL;DR
AB-training presents a communication-efficient, data-parallel approach that leverages low-rank weight representations and independent training groups to reduce interconnect traffic in distributed neural network training. By decomposing weight matrices into AB components and alternating training across A- and B-groups, then reconciling via synchronization and a subsequent full-rank rebound, the method achieves substantial traffic reductions with competitive accuracy across ImageNet and CIFAR-10 benchmarks. The work demonstrates ~70% average traffic reduction and variable compression ratios (e.g., up to 44.14:1 in CIFAR-10 with VGG16) while maintaining training times comparable to traditional DP; it also reveals regularization benefits at smaller scales but notes challenges with large-scale batch effects. These results suggest AB-training as a practical strategy for scalable, communication-efficient distributed training in HPC environments, with future work needed to refine update mechanisms and hyperparameter schedules for extreme-scale deployments.
Abstract
Communication bottlenecks severely hinder the scalability of distributed neural network training, particularly in high-performance computing (HPC) environments. We introduce AB-training, a novel data-parallel method that leverages low-rank representations and independent training groups to significantly reduce communication overhead. Our experiments demonstrate an average reduction in network traffic of approximately 70.31\% across various scaling scenarios, increasing the training potential of communication-constrained systems and accelerating convergence at scale. AB-training also exhibits a pronounced regularization effect at smaller scales, leading to improved generalization while maintaining or even reducing training time. We achieve a remarkable 44.14 : 1 compression ratio on VGG16 trained on CIFAR-10 with minimal accuracy loss, and outperform traditional data parallel training by 1.55\% on ResNet-50 trained on ImageNet-2012. While AB-training is promising, our findings also reveal that large batch effects persist even in low-rank regimes, underscoring the need for further research into optimized update mechanisms for massively distributed training.
