Collaborative Deep Learning Across Multiple Data Centers
This addresses data privacy and bandwidth issues for organizations with distributed data, though it is incremental as it builds on existing model averaging techniques.
The paper tackles the problem of training deep learning models across multiple data centers without centralizing data due to bandwidth and privacy constraints, showing that model averaging with cyclical learning rates and increased local epochs achieves competitive performance compared to centralized training.
Valuable training data is often owned by independent organizations and located in multiple data centers. Most deep learning approaches require to centralize the multi-datacenter data for performance purpose. In practice, however, it is often infeasible to transfer all data to a centralized data center due to not only bandwidth limitation but also the constraints of privacy regulations. Model averaging is a conventional choice for data parallelized training, but its ineffectiveness is claimed by previous studies as deep neural networks are often non-convex. In this paper, we argue that model averaging can be effective in the decentralized environment by using two strategies, namely, the cyclical learning rate and the increased number of epochs for local model training. With the two strategies, we show that model averaging can provide competitive performance in the decentralized mode compared to the data-centralized one. In a practical environment with multiple data centers, we conduct extensive experiments using state-of-the-art deep network architectures on different types of data. Results demonstrate the effectiveness and robustness of the proposed method.