C++ (Cpp) getFrequencyInMHz示例

示例#1

文件： platform.cpp 项目： Waferix/embree-renderer

  gettimeofday(&tvstart, NULL);
  cycles[0] = rdtsc();
  gettimeofday(&tvstart, NULL);
  usleep(250000);
  gettimeofday(&tvstop, NULL);
  cycles[1] = rdtsc();
  gettimeofday(&tvstop, NULL);
  
  const unsigned long microseconds = ((tvstop.tv_sec-tvstart.tv_sec)*1000000) + (tvstop.tv_usec-tvstart.tv_usec);
  unsigned long mhz = (unsigned long) (cycles[1]-cycles[0]) / microseconds;

  //PRINT(mhz);
  return (double)mhz;
}

  static double micFrequency = getFrequencyInMHz();

#endif

namespace embree
{
void* os_malloc(size_t bytes)
  {
    int flags = MAP_PRIVATE | MAP_ANON;
#if defined(__MIC__)
    if (bytes > 16*4096) {
      flags |= MAP_HUGETLB | MAP_POPULATE;
      bytes = (bytes+2*1024*1024-1)&(-2*1024*1024);
    } else {
      bytes = (bytes+4095)&(-4096);
    }

示例#2

文件： platform.cpp 项目： JianpingCAI/libigl

namespace embree
{
  void* os_malloc(size_t bytes)
  {
    int flags = MAP_PRIVATE | MAP_ANON;
#if defined(__MIC__)
    if (bytes > 16*4096) {
      flags |= MAP_HUGETLB | MAP_POPULATE;
      bytes = (bytes+2*1024*1024-1)&ssize_t(-2*1024*1024);
    } else {
      bytes = (bytes+4095)&ssize_t(-4096);
    }
#endif
    char* ptr = (char*) mmap(0, bytes, PROT_READ | PROT_WRITE, flags, -1, 0);
    if (ptr == NULL || ptr == MAP_FAILED) throw std::bad_alloc();
    return ptr;
  }

  void* os_reserve(size_t bytes)
  {
    int flags = MAP_PRIVATE | MAP_ANON | MAP_NORESERVE;
#if defined(__MIC__)
    if (bytes > 16*4096) {
      flags |= MAP_HUGETLB;
      bytes = (bytes+2*1024*1024-1)&ssize_t(-2*1024*1024);
    } else {
      bytes = (bytes+4095)&ssize_t(-4096);
    }
#endif
    char* ptr = (char*) mmap(0, bytes, PROT_READ | PROT_WRITE, flags, -1, 0);
    if (ptr == NULL || ptr == MAP_FAILED) throw std::bad_alloc();
    return ptr;
  }

  void os_commit (void* ptr, size_t bytes) {
  }

  void os_shrink(void* ptr, size_t bytesNew, size_t bytesOld) 
  {
    size_t pageSize = 4096;
#if defined(__MIC__)
    if (bytesOld > 16*4096) pageSize = 2*1024*1024;
#endif
    if (bytesNew & (pageSize-1)) 
      bytesNew = (bytesNew+pageSize) & (pageSize-1);

    os_free((char*)ptr+bytesNew,bytesOld-bytesNew);
  }

  void os_free(void* ptr, size_t bytes) 
  {
    if (bytes == 0)
      return;

#if defined(__MIC__)
    if (bytes > 16*4096) {
      bytes = (bytes+2*1024*1024-1)&ssize_t(-2*1024*1024);
    } else {
      bytes = (bytes+4095)&ssize_t(-4096);
    }
#endif
    if (munmap(ptr,bytes) == -1) {
      throw std::bad_alloc();
    }
  }

  void* os_realloc (void* old_ptr, size_t bytesNew, size_t bytesOld)
  {
#if defined(__MIC__)
    if (bytesOld > 16*4096)
      bytesOld = (bytesOld+2*1024*1024-1)&ssize_t(-2*1024*1024);
    else
      bytesOld = (bytesOld+4095)&ssize_t(-4096);

    if (bytesNew > 16*4096)
      bytesNew = (bytesNew+2*1024*1024-1)&ssize_t(-2*1024*1024);
    else
      bytesNew = (bytesNew+4095)&ssize_t(-4096);

    char *ptr = (char*)mremap(old_ptr,bytesOld,bytesNew,MREMAP_MAYMOVE);

    if (ptr == NULL || ptr == MAP_FAILED) {
      perror("os_realloc ");
      throw std::bad_alloc();
    }
    return ptr;
#else
    FATAL("not implemented");
    return NULL;
#endif

  }


#if defined(__MIC__)

  static double getFrequencyInMHz()
  {
    struct timeval tvstart, tvstop;
    unsigned long long int cycles[2];
    
    gettimeofday(&tvstart, NULL);
    cycles[0] = rdtsc();
    gettimeofday(&tvstart, NULL);
    usleep(250000);
    gettimeofday(&tvstop, NULL);
    cycles[1] = rdtsc();
    gettimeofday(&tvstop, NULL);
  
    const unsigned long microseconds = ((tvstop.tv_sec-tvstart.tv_sec)*1000000) + (tvstop.tv_usec-tvstart.tv_usec);
    unsigned long mhz = (unsigned long) (cycles[1]-cycles[0]) / microseconds;

    //std::cout << "MIC frequency is " << mhz << " MHz" << std::endl;
    return (double)mhz;
  }

  static double micFrequency = getFrequencyInMHz();

#endif

  double getSeconds() {
#if !defined(__MIC__)
    struct timeval tp; gettimeofday(&tp,NULL);
    return double(tp.tv_sec) + double(tp.tv_usec)/1E6;
#else
    return double(rdtsc()) / double(micFrequency*1E6);
#endif
  }
}