  The recent submission of Google TPU-v3 Pods to the industry wide MLPerf v0.6
training benchmark demonstrates the scalability of a suite of industry relevant
ML models. MLPerf defines a suite of models, datasets and rules to follow when
benchmarking to ensure results are comparable across hardware, frameworks and
companies. Using this suite of models, we discuss the optimizations and
techniques including choice of optimizer, spatial partitioning and weight
update sharding necessary to scale to 1024 TPU chips. Furthermore, we identify
properties of models that make scaling them challenging, such as limited data
parallelism and unscaled weights. These optimizations contribute to record
performance in transformer, Resnet-50 and SSD in the Google MLPerf-0.6
submission.
