Cerebro: A Data System for Optimized Deep Learning Model Selection

Deep neural networks (deep nets) are revolutionizing many machine learning (ML) applications. But there is a major bottleneck to wider adoption: the pain and resource intensiveness of model selection. This empirical process involves exploring deep net architectures and hyper-parameters, often requiring hundreds of trials. Alas, most ML systems focus on training one model at a time, reducing throughput and raising overall resource costs; some also sacrifice reproducibility. We present Cerebro, a new data system to raise deep net model selection throughput at scale without raising resource costs and without sacrificing reproducibility or accuracy. Cerebro uses a new parallel SGD execution strategy we call model hopper parallelism that hybridizes task- and data-parallelism to mitigate the cons of these prior paradigms and offer the best of both worlds. Experiments on large ML benchmark datasets show that Cerebro offers 3x to 10x runtime savings relative to data-parallel systems like Horovod and Parameter Server and up to 8x memory/storage savings or up to 100x network savings relative to task-parallel systems. Cerebro also supports heterogeneous resources and fault tolerance.