Rapid and Low-Cost Evaluation of Multi-fidelity Scheduling Algorithms for Hyperparameter Optimization.

Hyperparameter optimization (HPO), the process of searching for optimal hyperparameter configurations for a model, is becoming increasingly important with the rise of automated machine learning. Using HPO can be incredibly expensive as models increase in size. Multi-fidelity HPO schedulers attempt to more efficiently utilize resources given to each model configuration by determining the order they are evaluated in and the number of epochs they are run for. Pre-tabulated benchmarks are often used to reduce the compute power required to evaluate state-of-the-art schedulers. However, over-reliance on evaluation using these benchmarks can lead to overfitting. To solve this problem, we introduce a Platform for Hyperparameter Optimization Search Simulation (PHOSS), that enables rapid HPO scheduler evaluation by dynamically generating surrogate benchmarks. PHOSS uses a computationally efficient and expressive exponential decay parametric modeling approach to accurately generate surrogate benchmarks from real-world dataset samples without having to train an expensive surrogate model. We demonstrate that PHOSS can simulate several state-of-the-art schedulers on real-world benchmarks 4.5 × faster while also dramatically reducing multi-GPU compute requirements by enabling full testing of HPO schedulers on a single commodity CPU.