cuda-samples/Samples/simpleTemplates/simpleTemplates.cu

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/* This sample is a templatized version of the template project.
* It also shows how to correctly templatize dynamically allocated shared
* memory arrays.
* Host code.
*/

// System includes
#include <stdio.h>
#include <assert.h>
#include <string.h>
#include <math.h>

// CUDA runtime
#include <cuda_runtime.h>

// helper functions and utilities to work with CUDA
#include <helper_functions.h>
#include <helper_cuda.h>

#ifndef MAX
#define MAX(a, b) (a > b ? a : b)
#endif

// includes, kernels
#include "sharedmem.cuh"

int g_TotalFailures = 0;

////////////////////////////////////////////////////////////////////////////////
//! Simple test kernel for device functionality
//! @param g_idata  input data in global memory
//! @param g_odata  output data in global memory
////////////////////////////////////////////////////////////////////////////////
template <class T>
__global__ void testKernel(T *g_idata, T *g_odata) {
  // Shared mem size is determined by the host app at run time
  SharedMemory<T> smem;
  T *sdata = smem.getPointer();

  // access thread id
  const unsigned int tid = threadIdx.x;
  // access number of threads in this block
  const unsigned int num_threads = blockDim.x;

  // read in input data from global memory
  sdata[tid] = g_idata[tid];
  __syncthreads();

  // perform some computations
  sdata[tid] = (T)num_threads * sdata[tid];
  __syncthreads();

  // write data to global memory
  g_odata[tid] = sdata[tid];
}

////////////////////////////////////////////////////////////////////////////////
// declaration, forward
template <class T>
void runTest(int argc, char **argv, int len);

template <class T>
void computeGold(T *reference, T *idata, const unsigned int len) {
  const T T_len = static_cast<T>(len);

  for (unsigned int i = 0; i < len; ++i) {
    reference[i] = idata[i] * T_len;
  }
}

////////////////////////////////////////////////////////////////////////////////
// Program main
////////////////////////////////////////////////////////////////////////////////
int main(int argc, char **argv) {
  printf("> runTest<float,32>\n");
  runTest<float>(argc, argv, 32);
  printf("> runTest<int,64>\n");
  runTest<int>(argc, argv, 64);

  printf("\n[simpleTemplates] -> Test Results: %d Failures\n", g_TotalFailures);

  exit(g_TotalFailures == 0 ? EXIT_SUCCESS : EXIT_FAILURE);
}

// To completely templatize runTest (below) with cutil, we need to use
// template specialization to wrap up CUTIL's array comparison and file writing
// functions for different types.

// Here's the generic wrapper for cutCompare*
template <class T>
class ArrayComparator {
 public:
  bool compare(const T *reference, T *data, unsigned int len) {
    fprintf(stderr,
            "Error: no comparison function implemented for this type\n");
    return false;
  }
};

// Here's the specialization for ints:
template <>
class ArrayComparator<int> {
 public:
  bool compare(const int *reference, int *data, unsigned int len) {
    return compareData(reference, data, len, 0.15f, 0.0f);
  }
};

// Here's the specialization for floats:
template <>
class ArrayComparator<float> {
 public:
  bool compare(const float *reference, float *data, unsigned int len) {
    return compareData(reference, data, len, 0.15f, 0.15f);
  }
};

// Here's the generic wrapper for cutWriteFile*
template <class T>
class ArrayFileWriter {
 public:
  bool write(const char *filename, T *data, unsigned int len, float epsilon) {
    fprintf(stderr,
            "Error: no file write function implemented for this type\n");
    return false;
  }
};

// Here's the specialization for ints:
template <>
class ArrayFileWriter<int> {
 public:
  bool write(const char *filename, int *data, unsigned int len, float epsilon) {
    return sdkWriteFile(filename, data, len, epsilon, false);
  }
};

// Here's the specialization for floats:
template <>
class ArrayFileWriter<float> {
 public:
  bool write(const char *filename, float *data, unsigned int len,
             float epsilon) {
    return sdkWriteFile(filename, data, len, epsilon, false);
  }
};

////////////////////////////////////////////////////////////////////////////////
//! Run a simple test for CUDA
////////////////////////////////////////////////////////////////////////////////
template <class T>
void runTest(int argc, char **argv, int len) {
  int devID;
  cudaDeviceProp deviceProps;

  devID = findCudaDevice(argc, (const char **)argv);

  // get number of SMs on this GPU
  checkCudaErrors(cudaGetDeviceProperties(&deviceProps, devID));
  printf("CUDA device [%s] has %d Multi-Processors\n", deviceProps.name,
         deviceProps.multiProcessorCount);

  // create and start timer
  StopWatchInterface *timer = NULL;
  sdkCreateTimer(&timer);

  // start the timer
  sdkStartTimer(&timer);

  unsigned int num_threads = len;
  unsigned int mem_size = sizeof(float) * num_threads;

  // allocate host memory
  T *h_idata = (T *)malloc(mem_size);

  // initialize the memory
  for (unsigned int i = 0; i < num_threads; ++i) {
    h_idata[i] = (T)i;
  }

  // allocate device memory
  T *d_idata;
  checkCudaErrors(cudaMalloc((void **)&d_idata, mem_size));
  // copy host memory to device
  checkCudaErrors(
      cudaMemcpy(d_idata, h_idata, mem_size, cudaMemcpyHostToDevice));

  // allocate device memory for result
  T *d_odata;
  checkCudaErrors(cudaMalloc((void **)&d_odata, mem_size));

  // setup execution parameters
  dim3 grid(1, 1, 1);
  dim3 threads(num_threads, 1, 1);

  // execute the kernel
  testKernel<T><<<grid, threads, mem_size>>>(d_idata, d_odata);

  // check if kernel execution generated and error
  getLastCudaError("Kernel execution failed");

  // allocate mem for the result on host side
  T *h_odata = (T *)malloc(mem_size);
  // copy result from device to host
  checkCudaErrors(cudaMemcpy(h_odata, d_odata, sizeof(T) * num_threads,
                             cudaMemcpyDeviceToHost));

  sdkStopTimer(&timer);
  printf("Processing time: %f (ms)\n", sdkGetTimerValue(&timer));
  sdkDeleteTimer(&timer);

  // compute reference solution
  T *reference = (T *)malloc(mem_size);
  computeGold<T>(reference, h_idata, num_threads);

  ArrayComparator<T> comparator;
  ArrayFileWriter<T> writer;

  // check result
  if (checkCmdLineFlag(argc, (const char **)argv, "regression")) {
    // write file for regression test
    writer.write("./data/regression.dat", h_odata, num_threads, 0.0f);
  } else {
    // custom output handling when no regression test running
    // in this case check if the result is equivalent to the expected solution
    bool res = comparator.compare(reference, h_odata, num_threads);
    printf("Compare %s\n\n", (1 == res) ? "OK" : "MISMATCH");
    g_TotalFailures += (1 != res);
  }

  // cleanup memory
  free(h_idata);
  free(h_odata);
  free(reference);
  checkCudaErrors(cudaFree(d_idata));
  checkCudaErrors(cudaFree(d_odata));
}