pytorch

5e09c7bc - record unit time in torch.cuda.event (#15221)

record unit time in torch.cuda.event (#15221) Summary: Record unit of time for torch.cuda.Event's elapsed_time Differential Revision: D13467646 Pulled By: zou3519 fbshipit-source-id: 4f1f4ef5fa4bc5a1b4775dfcec6ab155e5bf8d6e