Add deprecation warning to PG backend and make TP backend stable.

[pritamdamania87]

Stack from ghstack:

• Add deprecation warning to PG backend and make TP backend stable. #45356 Add deprecation warning to PG backend and make TP backend stable.

In this PR, I'm adding a warning to the PG backend mentioning it would
be deprecated in the future. In addition to this I removed the warning from the
TP backend that it is a beta feature.

Differential Revision: D23940144

[dr-ci]

💊 CI failures summary and remediations

As of commit 7075e91 (more details on the Dr. CI page):

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• 2/2 failures introduced in this PR

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🕵️ 2 new failures recognized by patterns

The following CI failures do not appear to be due to upstream breakages:

pytorch_linux_xenial_cuda10_2_cudnn7_py3_gcc7_test (1/2)

Step: "Run tests" (full log | diagnosis details | 🔁 rerun)

Sep 25 23:53:40 [E request_callback_no_python.cpp:618] Received error while processing request type 2: RuntimeError: Can not pickle torch.futures.Future

Sep 25 23:53:40 At: 
Sep 25 23:53:40   /opt/conda/lib/python3.6/site-packages/torch/distributed/rpc/internal.py(94): serialize 
Sep 25 23:53:40   /opt/conda/lib/python3.6/site-packages/torch/distributed/rpc/internal.py(146): serialize 
Sep 25 23:53:40  
Sep 25 23:53:40 [E request_callback_no_python.cpp:618] Received error while processing request type 2: RuntimeError: Can not pickle torch.futures.Future 
Sep 25 23:53:40  
Sep 25 23:53:40 At: 
Sep 25 23:53:40   /opt/conda/lib/python3.6/site-packages/torch/distributed/rpc/internal.py(94): serialize 
Sep 25 23:53:40   /opt/conda/lib/python3.6/site-packages/torch/distributed/rpc/internal.py(146): serialize 
Sep 25 23:53:40  
Sep 25 23:53:40 [E request_callback_no_python.cpp:618] Received error while processing request type 2: RuntimeError: Can not pickle torch.futures.Future 
Sep 25 23:53:40  
Sep 25 23:53:40 At: 
Sep 25 23:53:40   /opt/conda/lib/python3.6/site-packages/torch/distributed/rpc/internal.py(94): serialize 
Sep 25 23:53:40   /opt/conda/lib/python3.6/site-packages/torch/distributed/rpc/internal.py(146): serialize 
Sep 25 23:53:40  
Sep 25 23:53:40 ok (1.226s) 
Sep 25 23:53:41   test_return_future_remote (__main__.ProcessGroupRpcTestWithSpawn) ... RPC was initialized with the PROCESS_GROUP backend which is deprecated and slated to be removed and superseded by the TENSORPIPE backend. It is recommended to migrate to the TENSORPIPE backend. 
Sep 25 23:53:41 RPC was initialized with the PROCESS_GROUP backend which is deprecated and slated to be removed and superseded by the TENSORPIPE backend. It is recommended to migrate to the TENSORPIPE backend. 
Sep 25 23:53:41 RPC was initialized with the PROCESS_GROUP backend which is deprecated and slated to be removed and superseded by the TENSORPIPE backend. It is recommended to migrate to the TENSORPIPE backend. 
Sep 25 23:53:41 RPC was initialized with the PROCESS_GROUP backend which is deprecated and slated to be removed and superseded by the TENSORPIPE backend. It is recommended to migrate to the TENSORPIPE backend. 

pytorch_linux_backward_compatibility_check_test (2/2)

Step: "Run tests" (full log | diagnosis details | 🔁 rerun)

Sep 25 21:13:32 The PR is introducing backward incompatible changes to the operator library. Please contact PyTorch team to confirm whether this change is wanted or not.

Sep 25 21:13:32 processing existing schema:  __setstate__(__torch__.torch.classes.quantized.EmbeddingPackedParamsBase _0, (int, Tensor[], float[], int[]) _1) -> (None _0) 
Sep 25 21:13:32 processing existing schema:  bit_rate(__torch__.torch.classes.quantized.EmbeddingPackedParamsBase _0) -> (int _0) 
Sep 25 21:13:32 processing existing schema:  version(__torch__.torch.classes.quantized.EmbeddingPackedParamsBase _0) -> (int _0) 
Sep 25 21:13:32 processing existing schema:  __getstate__(__torch__.torch.classes.xnnpack.LinearOpContext _0) -> ((Tensor, Tensor?, Scalar?, Scalar?) _0) 
Sep 25 21:13:32 processing existing schema:  __setstate__(__torch__.torch.classes.xnnpack.LinearOpContext _0, (Tensor, Tensor?, Scalar?, Scalar?) _1) -> (None _0) 
Sep 25 21:13:32 processing existing schema:  __getstate__(__torch__.torch.classes.xnnpack.Conv2dOpContext _0) -> ((Tensor, Tensor?, int[], int[], int[], int, Scalar?, Scalar?) _0) 
Sep 25 21:13:32 processing existing schema:  __setstate__(__torch__.torch.classes.xnnpack.Conv2dOpContext _0, (Tensor, Tensor?, int[], int[], int[], int, Scalar?, Scalar?) _1) -> (None _0) 
Sep 25 21:13:32 processing existing schema:  __getstate__(__torch__.torch.classes.xnnpack.TransposeConv2dOpContext _0) -> ((Tensor, Tensor?, int[], int[], int[], int[], int, Scalar?, Scalar?) _0) 
Sep 25 21:13:32 processing existing schema:  __setstate__(__torch__.torch.classes.xnnpack.TransposeConv2dOpContext _0, (Tensor, Tensor?, int[], int[], int[], int[], int, Scalar?, Scalar?) _1) -> (None _0) 
Sep 25 21:13:32 processing existing schema:  __init__(__torch__.torch.classes.dist_rpc.WorkerInfo _0, str _1, int _2) -> (None _0) 
Sep 25 21:13:32 The PR is introducing backward incompatible changes to the operator library. Please contact PyTorch team to confirm whether this change is wanted or not.  
Sep 25 21:13:32  
Sep 25 21:13:32 Broken ops: [ 
Sep 25 21:13:32 	static::mul.a(Tensor a, Tensor b) -> (Tensor) 
Sep 25 21:13:32 	static::mul.b(Tensor a, int b) -> (Tensor) 
Sep 25 21:13:32 	static::add(Tensor a, Tensor b) -> (Tensor) 
Sep 25 21:13:32 ] 
Sep 25 21:13:32 + cleanup 
Sep 25 21:13:32 + retcode=1 
Sep 25 21:13:32 + set +x 
Sep 25 21:13:32 =================== sccache compilation log =================== 

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This comment has been revised 2 times.

[facebook-github-bot]

This pull request has been merged in 3b7e4f8.