pytorch

1721137f - [PyTorch] Use native serial stack when there is only 1 thread (#76399)

[PyTorch] Use native serial stack when there is only 1 thread (#76399) Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/76399 Does not make sense to hit the non-serial kernel if intra op parallelism is off. ghstack-source-id: 154934866 Test Plan: Existing unit tests Reviewed By: tenpercent Differential Revision: D35946012 fbshipit-source-id: 9ae12e267826b4da96b0a105c34260bc4ac91135 (cherry picked from commit f61eb10a754cab5491ec972b72aa5e92e0638e50)