416fccb5cd
Both allocation to a cuda graph's private pool via stream capture and allocation to a memory pool in non-stream-captured code are supported. In the case of stream capture, we refuse to reuse a host memory block as soon as record_event() is called on that block. This is to prevent a stream-captured CUDA kernel from reading different contents from a memory block than would be read if, counterfactually, this CUDA kernels were running eagerly on a cuda stream. See https://github.com/pytorch/pytorch/pull/161583#issuecomment-3229885771 for elaboration. This is lacking test cases for pagedable host memory copies. We must make sure that record_event() does not fail in that case. Pull Request resolved: https://github.com/pytorch/pytorch/pull/167507 Approved by: https://github.com/eqy, https://github.com/eee4017, https://github.com/ngimel
c10/cuda is a core library with CUDA functionality. It is distinguished from c10 in that it links against the CUDA library, but like c10 it doesn't contain any kernels, and consists solely of core functionality that is generally useful when writing CUDA code; for example, C++ wrappers for the CUDA C API.
Important notes for developers. If you want to add files or functionality to this folder, TAKE NOTE. The code in this folder is very special, because on our AMD GPU build, we transpile it into c10/hip to provide a ROCm environment. Thus, if you write:
// c10/cuda/CUDAFoo.h
namespace c10 { namespace cuda {
void my_func();
}}
this will get transpiled into:
// c10/hip/HIPFoo.h
namespace c10 { namespace hip {
void my_func();
}}
Thus, if you add new functionality to c10, you must also update C10_MAPPINGS
torch/utils/hipify/cuda_to_hip_mappings.py to transpile
occurrences of cuda::my_func to hip::my_func. (At the moment,
we do NOT have a catch all cuda:: to hip:: namespace conversion,
as not all cuda namespaces are converted to hip::, even though
c10's are.)
Transpilation inside this folder is controlled by CAFFE2_SPECIFIC_MAPPINGS
(oddly enough.) C10_MAPPINGS apply to ALL source files.
If you add a new directory to this folder, you MUST update both c10/cuda/CMakeLists.txt and c10/hip/CMakeLists.txt