Problem with multiGPU code using cuda Threads to launch the same kernel to multiple GPUs

[Thmmy]

1. How do you verify that the data was transferred correctly to both GPUs?

2. Are you following one of the multi-GPU samples in the SDK? If so, what’s different between your code and the sample?

Paulius

For the transportation of the data i allocate memory in the CUT_THREADPROC routine using CudaMalloc and then i copy them to

the GPUs using cudaMemcpy. So each thread does the same thing for each device and returns the data to a different matrix which is

declared as a pointer in a strucrure.

I do that with the following code:

[i]

CUDA_SAFE_CALL(cudaSetDevice(str->real_device));

CUDA_SAFE_CALL(cudaGetDevice(&dev));

printf(“The device running now is %d\n”, dev);

CUDA_SAFE_CALL( cudaMalloc((void**)&d_Pad_Frame, str->PAD_FRAME_SIZE_PER_DEVICE));

CUDA_SAFE_CALL( cudaMalloc((void**)&d_OutcomeGPU, str->OUTCOME_SIZE_PER_DEVICE));

gettimeofday (&str->start_in, NULL);

CUDA_SAFE_CALL( cudaMemcpyToSymbol(d_Template, h_Template, TEMPLATE_SIZE));

CUDA_SAFE_CALL( cudaMemcpy(d_Pad_Frame, str->h_Pad_Frame, str->PAD_FRAME_SIZE_PER_DEVICE, cudaMemcpyHostToDevice));

gettimeofday (&str->end_in, NULL);

CUDA_SAFE_CALL( cudaMemcpy(str->test_Pad_Frame, d_Pad_Frame, str->PAD_FRAME_SIZE_PER_DEVICE, cudaMemcpyDeviceToHost) );

Printing_Matrix(PAD_FRAME_M, str->PAD_FRAME_SIZE_PER_DEVICE/(PAD_FRAME_M * sizeof(float)), str->test_Pad_Frame);

[/i]

So actually i print the matrices.

For the second thing you ask: In order to launch the threads i use the steps of the MonteCarloMultiGpu from NVIDIA CUDA SDK