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I am writing a library that uses a surface (to re-sample and write to a texture) for a performance gain:

...
surface<void,  2> my_surf2D; //allows writing to a texture
...

The target platform GPU has compute capability 2.0 and I can compile my code with:

nvcc -arch=sm_20 ...

and it works just fine.

The problem is when I am trying to develop and debug the library on my laptop which has an NVIDIA ION GPU with compute capability 1.1 (I would also like my library to be backwards compatible). I know this architecture does not support surfaces so I used the nvcc macros in my device code to define an alternate code path for this older architecture:

#if (__CUDA_ARCH__ < 200)
#warning using kernel for CUDA ARCH < 2.0
...
temp_array[...] =  tex3D(my_tex,X,Y,Z+0.5f);
#else
...
surf2Dwrite( tex3D(my_tex,X,Y,Z+0.5f), my_surf2D, ix*4, iy,cudaBoundaryModeTrap);
#endif

The problem is that when I do:

nvcc -gencode arch=compute_11,code=sm_11

I get this error:

ptxas PTX/myLibrary.ptx, line 1784; fatal  : Parsing error near '.surf': syntax error

When I look at the PTX file is see what appears to be the surface declaration:

.surf .u32 _ZN16LIB_15my_surf2DE;

If I try to put a similar macro around the surface declaration in my source code:

#ifdef __CUDACC__
#if __CUDA_ARCH__ < 200
#warning skipping surface declaration for nvcc trajectory
#else
surface ...
#endif
#else
#warning keeping surface declaration by default
surface ...
#endif

I get an error saying the surface variable is undefined in the host code call to to bind cuda surface to array. Should I add the macro around the bind function as well?

I'm not sure if it is possible, or if I goofed somewhere, please help.

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このスレッドは回答済みとして表示されるはずだと考えました...

私はそれを機能させました（実際には非常に簡単です）。サーフェス参照が使用される可能性のある3 つの場所すべてにマクロを配置する必要があり、マクロを適切に使用するように注意してください (__CUDACC__ は不要であることがわかりました)。

以下は、コンピューティング機能 < 2.0 用にコンパイルする場合にのみコードを変更します。

表面宣言:

//enable backwards compatability:
#if defined(__CUDA_ARCH__) & (__CUDA_ARCH__ < 200)
#warning skipping surface declarations for compute capability < 2.0
#else
surface<void,  2> my_surf2D; //allows writing to a texture
#endif

表面結合:

#if defined(__CUDA_ARCH__) & (__CUDA_ARCH__ < 200)
#warning skipping cudaBindSurfaceToArray for compute capability < 2.0
...
#else
errorCode = cudaBindSurfaceToArray(my_surf2D, my_cudaArray2D);
#endif

そしてSurfaceの書き込み：

#if defined(__CUDA_ARCH__) & (__CUDA_ARCH__ < 200)
#warning using kernel for compute capability < 2.0
...
temp_array[...] =  tex3D(my_tex,X,Y,Z+0.5f);
#else
...
surf2Dwrite( tex3D(my_tex,X,Y,Z+0.5f), my_surf2D, ix*4, iy,cudaBoundaryModeTrap);
#endif

これは、仮想ターゲットと実際のターゲットの両方で機能します (それぞれ -arch=compute_XX と -arch=sm_XX)。

私を正しい方向に向けてくれたtalonmiesとRoger Dahlに感謝します。また、nvcc/CUDA マクロの優れた説明があるtalonmiesからのこの回答にも感謝します。

于 2012-04-16T07:44:14.297 に答える