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SWDEV-265003 - update HIP document

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Change-Id: I1e8ec3ad380330b48d164a2ca60b0a70f7e54ae6
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jujiang
2021-01-19 19:28:16 -05:00
committed by Julia Jiang
parent ecdbaf73cf
commit 6084d0da2d
1 changed files with 6 additions and 4 deletions
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docs/markdown/hip_porting_guide.md
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@@ -147,9 +147,11 @@ directory names.
### Identifying HIP Target Platform
All HIP projects target either AMD or NVIDIA platform. The platform affects which headers are included and which libraries are used for linking.
- `HIP_PLATFORM_AMD` is defined if the HIP platform targets AMD
- `HIP_PLATFORM_AMD` is defined if the HIP platform targets AMD.
Note, `HIP_PLATFORM_HCC` was previously defined if the HIP platform targeted AMD, it is deprecated.
- `HIP_PLATFORM_NVIDA` is defined if the HIP platform targets NVIDIA
- `HIP_PLATFORM_NVIDA` is defined if the HIP platform targets NVIDIA.
Note, `HIP_PLATFORM_NVCC` was previously defined if the HIP platform targeted NVIDIA, it is deprecated.
### Identifying the Compiler: hip-clang or nvcc
Often, it's useful to know whether the underlying compiler is HIP-Clang or nvcc. This knowledge can guard platform-specific code or aid in platform-specific performance tuning.
@@ -189,7 +191,6 @@ HIP-Clang will have multiple passes over the code: one for the host code, and on
Unlike `__CUDA_ARCH__`, the `__HIP_DEVICE_COMPILE__` value is 1 or undefined, and it doesn't represent the feature capability of the target device.
### Compiler Defines: Summary
|Define | HIP-Clang | nvcc | Other (GCC, ICC, Clang, etc.)
|--- | --- | --- |---|
@@ -286,9 +287,10 @@ HIP can depend on ROCclr, or NVCC as runtime
- AMD platform
On AMD platform, HIP uses Radeon Open Compute Common Language Runtime, called ROCclr.
ROCclr is a virtual device interface that HIP runtimes interact with different backends which allows runtimes to work on Linux , as well as Windows without much efforts.
Note, `HIP_ROCclr` needed to be defined on AMD platform that HIP used ROCclr, only when platform was defined as deprecated `HIP_PLATFORM_HCC`.
- NVIDIA platform
On Nvidia platform, HIP is just a thin layer on top of CUDA.
On non-AMD platform, HIP runtime determines if nvcc is available and can be used. If available, HIP_PLATFORM is set to nvcc and underneath CUDA path is used.