pytorch

30997320 - Creates device generic cuDNN decorators (#26791)

Creates device generic cuDNN decorators (#26791) Summary: - Creates skipCUDAIfNoCudnn, skipCUDAIfCudnnVersionLessThan decorators - Makes several test_nn.py tests generic Many tests in test_nn.py test cuDNN. These tests are guarded on various conditionals using TEST_CUDNN and TEST_CUDNN_VERSION imported from common_cuda.py and custom error messages like 'CUDNN not available' and 'needs cudnn.' This PR suggests using the CUDA base test class instead of common_cuda.py to test cuDNN's availability, at least on generic tests. The CUDA base test class is preferable to common_cuda.py since it only creates a CUDA context if its tests are run. Importing from common_cuda.py, on the other hand, always creates a CUDA context. Using the CUDA base test class is also consistent with how other generic tests are guarded and provides consistent skip messages. One quirk to this approach is that it makes use of the self argument to the test functions to check for cuDNN availability during a test. See test_rnn_retain_variables. The self argument could also be used to check the device type instead of the more verbose torch.device(device).type == 'cuda'. An alternative approach to making test_nn.py generic would be to continue to use common_cuda.py imports, try to keep their skip messages consistent, and not worry about creating unnecessary CUDA contexts. This would preclude writing generic tests that can only run on CUDA if cuDNN is available, however, so tests like "_test_RNN_cpu_vs_cudnn" would require additional changes to make into device generic precision tests like "_test_RNN_cpu_vs_xla." For consistency, simplicity, and ease of use, I recommend we adopt the proposed decorators and make use of the self argument when productive. Pull Request resolved: https://github.com/pytorch/pytorch/pull/26791 Differential Revision: D17678325 Pulled By: mruberry fbshipit-source-id: 1794735ede9bc9f36856e72b3804b136ad3e0de2