Perf test

perf_test.cpp

 template <typename F>
    static void measure(float& avg, float& med, float& min, float& max, F&& func) {
      LARGE_INTEGER b, e, f;

      enum { ITERS = 10 };
      LONGLONG dur[ITERS];
      LONGLONG sum = 0;
      for (int i = 0; i < 5; ++i) {
        func();
      }
      for (int i = 0; i < ITERS; ++i) {
        QueryPerformanceCounter(&b);
        func();
        QueryPerformanceCounter(&e);
        dur[i] = e.QuadPart - b.QuadPart;
        sum += e.QuadPart - b.QuadPart;
        Sleep(1);
      }
      std::sort(dur, dur + ITERS);
      QueryPerformanceFrequency(&f);
      avg = float(double(sum) / double(f.QuadPart) * 1000.0 / ITERS);
      med = float(double(dur[ITERS / 2]) / double(f.QuadPart) * 1000.0);
      min = float(double(dur[0]) / double(f.QuadPart) * 1000.0);
      max = float(double(dur[ITERS - 1]) / double(f.QuadPart) * 1000.0);
      char tmp[1024];
      sprintf_s(tmp, "avg = %fms\nmed = %fms\nmin = %fms\nmax = %fms\n", avg, med, min, max);
      OutputDebugString(tmp);
    }