[Distributed] General Function for Parsing Environment Variable Flags in PG (#46045)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/46045
PG NCCL functionality differs based on certain binary environment
variables such as NCCL_BLOCKING_WAIT and NCCL_ASYNC_ERROR_HANDLING. Previously
we had separate helper function to parse these env vars and set class variables
accordingly. This PR introduces a general purpose function for this purpose.
ghstack-source-id: 114209823
Test Plan:
Ran the following flow with NCCL_BLOCKING_WAIT set, and ensured the
ProcessGroup constructor set blcokingWait_ to true: f223454701
Reviewed By: jiayisuse
Differential Revision: D24173982
fbshipit-source-id: b84db2dda29fcf5d163ce8860e8499d5070f8818
