add function to get nccl version for error messages (#27068)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/27068
Adds a function that uses ncclGetVersion from the NCCL API to retrieve the NCCL version. Converts it into a readable string, and is called in NCCL-related error messages to log the NCCL version. Hopefully this will help with debugging NCCL errors.
Test Plan:
Modify C10D_NCCL_CHECK in NCCLUtils.hpp to always error by setting ncclResult_t error = ncclSystemError
force an NCCL error with script test/simulate_nccl_errors.py:
Start master node: python test/simulate_nccl_errors.py localhost 9124 0 2
Start other node: python test/simulate_nccl_errors.py localhost 9124 1 2
On the master node, should see the following error message w/NCCL version:
```
Traceback (most recent call last):
File "simulate_nccl_errors.py", line 29, in <module>
process_group.allreduce(torch.rand(10).cuda(rank)).wait()
RuntimeError: NCCL error in: ../torch/lib/c10d/ProcessGroupNCCL.cpp:375, unhandled system error, NCCL version 2.4.8
```
Differential Revision: D17639476
fbshipit-source-id: a2f558ad9e883b6be173cfe758ec56cf140bc1ee
