Browser Support • Measuring JavaScript execution time

Is there a way to get more precision out of performance.now() on UXP? Because it seems to be returning plain integer, for one thing I'm measuring, either 0 or 16 (ms), nothing in between. I'm looking for something like WIN32's QueryPerformanceCounter() or at least timeGetTime(), for JavaScript, but all I'm getting on UXP is more like GetTickCount().