#define NANOS_PER_SEC         CONST64(1000000000)

static jlong performance_frequency;

static void initialize_performance_counter() {
  LARGE_INTEGER count;
  if (QueryPerformanceFrequency(&count)) {
    has_performance_count = 1;
    performance_frequency = as_long(count);
    QueryPerformanceCounter(&count);
    initial_performance_count = as_long(count);
  } else {
    has_performance_count = 0;
    FILETIME wt;
    GetSystemTimeAsFileTime(&wt);
    first_filetime = jlong_from(wt.dwHighDateTime, wt.dwLowDateTime);
  }
}


    LARGE_INTEGER current_count;
    QueryPerformanceCounter(&current_count);
    double current = as_long(current_count);
    double freq = performance_frequency;
    jlong time = (jlong)((current/freq) * NANOS_PER_SEC);
    return time;


D:\Knova\native_repo\boost_1_43_0\libs\spirit\optimization\high_resolution_timer.hpp

// Now start a timer
util::high_resolution_timer time;
// ... some actions
double elapsed = time.elapsed();          // return the elapsed time