Cuda-从设备全局内存复制到纹理内存

我正试图使用Cuda和C++在GPU上执行两项任务(分为两个内核)。作为输入，我取一个NxM矩阵(作为浮点数组存储在主机的内存中)。然后，我将使用一个内核对这个矩阵执行一些操作，使其成为NxMxD矩阵。然后我有了第二个内核，它对这个3D矩阵执行一些操作(我只读取值，不必向它写入值)。

对于我的任务来说，在纹理内存中操作似乎要快得多，所以我的问题是，是否可以在内核1之后从设备上的全局内存复制我的数据，并将其直接传输到内核2的纹理内存，而不将其带回主机？

更新

我添加了一些代码来更好地说明我的问题。

这是两个果仁。第一个现在只是一个占位符，并将2D矩阵复制到3D中。

__global__ void computeFeatureVector(float* imData3D_dev, int imX, int imY, int imZ) {
//calculate each thread global index  
int xindex=blockIdx.x*blockDim.x+threadIdx.x; 
int yindex=blockIdx.y*blockDim.y+threadIdx.y;     
#pragma unroll
for (int z=0; z<imZ; z++) { 
imData3D_dev[xindex+yindex*imX + z*imX*imY] = tex2D(texImIp,xindex,yindex);
}
}

第二个将使用这个3D矩阵，现在表示为纹理，并对其执行一些操作。目前为空白。

__global__ void kernel2(float* resData_dev, int imX) {
//calculate each thread global index  
int xindex=blockIdx.x*blockDim.x+threadIdx.x; 
int yindex=blockIdx.y*blockDim.y+threadIdx.y;     
resData_dev[xindex+yindex*imX] = tex3D(texImIp3D,xindex,yindex, 0);
return; 
} 

然后代码的主体如下：

// declare textures
texture<float,2,cudaReadModeElementType> texImIp; 
texture<float,3,cudaReadModeElementType> texImIp3D; 
void main_fun() {
// constants
int imX = 1024;
int imY = 768;
int imZ = 16;
// input data
float* imData2D  = new float[sizeof(float)*imX*imY];        
for(int x=0; x<imX*imY; x++)
imData2D[x] = (float) rand()/RAND_MAX;
//create channel to describe data type 
cudaArray* carrayImIp; 
cudaChannelFormatDesc channel; 
channel=cudaCreateChannelDesc<float>();  
//allocate device memory for cuda array 
cudaMallocArray(&carrayImIp,&channel,imX,imY);
//copy matrix from host to device memory  
cudaMemcpyToArray(carrayImIp,0,0,imData2D,sizeof(float)*imX*imY,cudaMemcpyHostToDevice); 
// Set texture properties
texImIp.filterMode=cudaFilterModePoint;
texImIp.addressMode[0]=cudaAddressModeClamp; 
texImIp.addressMode[1]=cudaAddressModeClamp; 
// bind texture reference with cuda array   
cudaBindTextureToArray(texImIp,carrayImIp);
// kernel params
dim3 blocknum; 
dim3 blocksize;
blocksize.x=16; blocksize.y=16; blocksize.z=1; 
blocknum.x=(int)ceil((float)imX/16);
blocknum.y=(int)ceil((float)imY/16);    
// store output here
float* imData3D_dev;        
cudaMalloc((void**)&imData3D_dev,sizeof(float)*imX*imY*imZ); 
// execute kernel
computeFeatureVector<<<blocknum,blocksize>>>(imData3D_dev, imX, imY, imZ); 
//unbind texture reference to free resource 
cudaUnbindTexture(texImIp); 
// check copied ok
float* imData3D  = new float[sizeof(float)*imX*imY*imZ];
cudaMemcpy(imData3D,imData3D_dev,sizeof(float)*imX*imY*imZ,cudaMemcpyDeviceToHost);     
cout << " kernel 1" << endl;
for (int x=0; x<10;x++)
cout << imData3D[x] << " ";
cout << endl;
delete [] imData3D;

//
// kernel 2
//

// copy data on device to 3d array
cudaArray* carrayImIp3D;
cudaExtent volumesize;
volumesize = make_cudaExtent(imX, imY, imZ);
cudaMalloc3DArray(&carrayImIp3D,&channel,volumesize); 
cudaMemcpyToArray(carrayImIp3D,0,0,imData3D_dev,sizeof(float)*imX*imY*imZ,cudaMemcpyDeviceToDevice); 
// texture params and bind
texImIp3D.filterMode=cudaFilterModePoint;
texImIp3D.addressMode[0]=cudaAddressModeClamp; 
texImIp3D.addressMode[1]=cudaAddressModeClamp; 
texImIp3D.addressMode[2]=cudaAddressModeClamp;
cudaBindTextureToArray(texImIp3D,carrayImIp3D,channel); 
// store output here
float* resData_dev;
cudaMalloc((void**)&resData_dev,sizeof(float)*imX*imY); 
// kernel 2
kernel2<<<blocknum,blocksize>>>(resData_dev, imX); 
cudaUnbindTexture(texImIp3D);
//copy result matrix from device to host memory   
float* resData  = new float[sizeof(float)*imX*imY];
cudaMemcpy(resData,resData_dev,sizeof(float)*imX*imY,cudaMemcpyDeviceToHost); 
// check copied ok
cout << " kernel 2" << endl;
for (int x=0; x<10;x++)
cout << resData[x] << " ";
cout << endl;

delete [] imData2D;
delete [] resData;
cudaFree(imData3D_dev);  
cudaFree(resData_dev);
cudaFreeArray(carrayImIp); 
cudaFreeArray(carrayImIp3D); 
}

我很高兴第一个内核工作正常，但3D矩阵imData3D_dev似乎没有正确绑定到纹理texImIp3D。

答案

我用cudaMemcpy3D解决了我的问题。这里是修改后的代码的第二部分的主要功能。imData3D_dev包含来自第一内核的全局存储器中的3D矩阵。

cudaArray* carrayImIp3D;
cudaExtent volumesize;
volumesize = make_cudaExtent(imX, imY, imZ);
cudaMalloc3DArray(&carrayImIp3D,&channel,volumesize); 
cudaMemcpy3DParms copyparms={0};
copyparms.extent = volumesize;
copyparms.dstArray = carrayImIp3D;
copyparms.kind = cudaMemcpyDeviceToDevice;  
copyparms.srcPtr = make_cudaPitchedPtr((void*)imData3D_dev, sizeof(float)*imX,imX,imY); 
cudaMemcpy3D(&copyparms);
// texture params and bind
texImIp3D.filterMode=cudaFilterModePoint;
texImIp3D.addressMode[0]=cudaAddressModeClamp; 
texImIp3D.addressMode[1]=cudaAddressModeClamp; 
texImIp3D.addressMode[2]=cudaAddressModeClamp;
cudaBindTextureToArray(texImIp3D,carrayImIp3D,channel); 
// store output here
float* resData_dev;
cudaMalloc((void**)&resData_dev,sizeof(float)*imX*imY); 
kernel2<<<blocknum,blocksize>>>(resData_dev, imX); 
// ... clean up