pytorch

e57a0811 - Add a warning log when there is high skew of uneven inputs in DDP training (#45238)

Add a warning log when there is high skew of uneven inputs in DDP training (#45238) Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/45238 Adds a warning when there is much higher than expected amount of discrepancy of inputs across different processes when running with uneven inputs. This is because a skew in the thousands can reduce performance a nontrivial amount as shown in benchmarks, and it was proposed to add this warning as a result. Tested by running the tests so the threshold is hit and observing the output. ghstack-source-id: 112773552 Test Plan: CI Reviewed By: mrshenli Differential Revision: D23719270 fbshipit-source-id: 306264f62c1de65e733696a912bdb6e9376d5622