Data Parallelism: From Parameter Server to Ring All-Reduce
Data Parallelism: From Parameter Server to Ring All-Reduce Data parallelism is the default scaling move because it preserves the model program. Every rank owns the same model, sees different examples, computes gradients, and applies the same update. The algorithm is simple. The system is not. The whole post is about removing one bottleneck: do not push all gradient traffic through one server when every GPU could be moving bytes at the same time. ...