pytorch

bfffc8d8 - [DDP][Docs] Add warning that `no_sync()` should include forward (#89244)

[DDP][Docs] Add warning that `no_sync()` should include forward (#89244) The issue where the user only includes `loss.backward()` inside `no_sync()` but not the forward pass has arisen several times now. I think adding an explicit warning in the docs is worthwhile. Rendered doc: <img width="769" alt="Screen Shot 2022-11-17 at 9 21 32 PM" src="https://user-images.githubusercontent.com/31054793/202602005-22c000b7-1093-4eaf-ba66-9c929a66906b.png"> Pull Request resolved: https://github.com/pytorch/pytorch/pull/89244 Approved by: https://github.com/zhaojuanmao