pytorch

a9aa6367 - [futures] Add torch.futures.collect_all()/wait_all() python api. (#39790)

[futures] Add torch.futures.collect_all()/wait_all() python api. (#39790) Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/39790 The "[fut.wait() for fut in futs]" idiom can introduce up to O(len(futs)) thread switches, which may be excessive for large N. This plumbs through the new c++ c10::collectAll() to Python space so that we only employ a single jit-side wait. ghstack-source-id: 105779443 Test Plan: buck test mode/dev-nosan caffe2/test/distributed/rpc:rpc_spawn Reviewed By: kiukchung Differential Revision: D21976891 fbshipit-source-id: 253c61f503f4ffb9be784e6c49a0656cede139fb