How to pass device function as an input argument to host-side function?

问题

I just want to pass device function as argument of a host function, of cause, the host function then can launch some kernels with this device side function.

I tried the usual C++ way (pass by pointer/reference) and the CUDA debugger told me the kernel cannot launch.

Update:

What I want to do is:

__host__ void hostfunction(int a, int (*DeviceFunction)(int))
{
   /...do something.../
   somekernel<<<blocks, threads>>>(int * in, DeviceFunction);
}

And launch the host with:

hostfunction(x, &SomeDeviceFunctionTemplate<int>);

回答1:

This example might be of interest:

$ cat t237.cu
#include <stdio.h>


__device__ int f1(){ printf("dev f1\n"); return 0;}
__device__ int f2(){ printf("dev f2\n"); return 0;}
__device__ int f3(){ printf("dev f3\n"); return 0;}

__device__ int *fptrf1 = (int *)f1;
__device__ int *fptrf2 = (int *)f2;
__device__ int *fptrf3 = (int *)f3;


__global__ void mykernel(int (*fptr)()){

  fptr();
  printf("executed\n");
}

int main(){

  int *hf1, *hf2, *hf3;
  cudaMemcpyFromSymbol(&hf1, fptrf1, sizeof(int *));
  cudaMemcpyFromSymbol(&hf2, fptrf2, sizeof(int *));
  cudaMemcpyFromSymbol(&hf3, fptrf3, sizeof(int *));
  mykernel<<<1,1>>>((int (*)())hf1);
  cudaDeviceSynchronize();
  mykernel<<<1,1>>>((int (*)())hf2);
  cudaDeviceSynchronize();
  mykernel<<<1,1>>>((int (*)())hf3);
  cudaDeviceSynchronize();
  return 0;
}
$ nvcc -arch=sm_20 -O3 -o t237 t237.cu
$ ./t237
dev f1
executed
dev f2
executed
dev f3
executed
[bob@cluster1 misc]$

I think this is roughly along the lines of what Jared was suggesting. As he mentioned, this will not be possible in host code:

&SomeDeviceFunctionTemplate<int>

Assuming SomeDeviceFunctionTemplate refers to a __device__ function.

回答2:

It'd be helpful if you could post an example of what you are trying to do, but one thing to check is that you are compiling and running on Fermi (sm_20) or later since older GPUs did not support non-inlined function calls.

Check the compute capability of your device (needs 2.0 or later) and check your nvcc command line (needs -arch=sm_20 or later, or the -gencode equivalent).

来源：https://stackoverflow.com/questions/18485990/how-to-pass-device-function-as-an-input-argument-to-host-side-function

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