at::launch benchmark (#21581)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/21581
ghimport-source-id: 6a65d73694b17611d6ad45db0b39b86c318a68c7
Differential Revision: D15736495
Pulled By: ilia-cher
fbshipit-source-id: 6b9109ad3611ff3c8b1a37796e9149bef0c2ad36
