Constant memory hangs system constant memory access

Accelerated Computing CUDA CUDA Programming and Performance
1

this works. i made a alg bug. and extern should be in kernel, not global.

__constant__ int c_idata[1024];	//can i use int* here, and cudamalloc later?

..

	//CUDA_SAFE_CALL( cudaMemcpy( c_idata, h_idata, sizeof(int) * nR, cudaMemcpyHostToDevice) );

	CUDA_SAFE_CALL(cudaMemcpyToSymbol(c_idata, h_idata, sizeof(int) * nR, 0));

//both hangs system

	dim3 Dg(2, 1, 1);

	dim3 Db(2, 1, 1);

testKernel<<<Dg, Db>>>(d_odata,  nR);

CUT_CHECK_ERROR("Kernel partitioning execution failed");

//kernel:

 extern  __constant__ int c_idata[1024];

__global__ void

testKernel(int* d_odata, const int nR) 

{

	int bx = blockIdx.x;

	int tx = threadIdx.x;

	int blockSize = nR / gridDim.x;

	int loopTimes = blockSize/blockDim.x;

	int dataIdx;

	for( int i = 0; i < loopTimes; i++ )

	{

  dataIdx = blockSize * bx + i * blockDim.x + tx;

  

  for( int j = 0; j < 1023; j++ )

  {

    //this hangs systerm: d_odata[dataIdx + 1] = c_idata[dataIdx];

//should be: 

d_odata[dataIdx] = c_idata[dataIdx];

 }  

	}

}
2

constant int c_idata[1024]; //can’t use int* here, and cudamalloc later.