[c10d] Use pg wrapper in detailed debug mode (#58281)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/58281
When TORCH_DISTRIBUTED_DEBUG=DETAIL is enabled, this PR causes process groups created by `new_group` and `init_process_group` that are nccl or gloo to be wrapped in `ProcessGroupWrapper`.
As a result, the user will get back a `ProcessGroupWrapper` that they can use in the exact same way as a regular nccl/gloo pg, but will be more helpful in terms of debugging desync/hangs.
Besides doing collective desync checks, which should be transparent if there are indeed no issues in the user application, there are no semantic differences in using the wrapper pg. Note that there is a performance implication here but that is a tradeoff we are making when DETAIL debug mode is enabled.
Open to suggestions on how to test better. Currently I verified locally that enabling TORCH_DISTRIBUTED_DEBUG=detail creates the wrapper and all tests still pass, but that doesn't run in CI. On the other hand testing everything with debug=detail and the regular tests might be too much, so we have only added it to a few tests for now. We also do have tests in the below diff.
ghstack-source-id: 129817857
Test Plan: ci
Reviewed By: SciPioneer
Differential Revision: D28402301
fbshipit-source-id: c4d3438320f6f0986e128c738c9d4a87bbb6eede
