xla

db0c7e80 - Add performance profiling tool to enable programmatic/interactive/automatic PT-XLA profile capturing (#3498)

Add performance profiling tool to enable programmatic/interactive/automatic PT-XLA profile capturing (#3498) * Add performance profiling tool to enable programmatic/interactive/automatic PT-XLA profile capturing * Update README to document capture_profile.py * Add module docstring to capture_profile.py * Add instructions on how to run tensorboard in module docstring for capture_profile.py * Reformat capture_profile.py using yapf