睡眠(1)和SDL_Delay(1)需要15 ms

I am writing a C++/SDL/OpenGL application, and I have had the most peculiar bug. The game seemed to be working fine with a simple variable timestep. But then the FPS started behaving strangely. I figured out that both Sleep(1) and SDL_Delay(1) take 15 ms to complete.I am writing a C++/SDL/OpenGL application, and