Complex sentence: It measures time in milliseconds (though it does not have millisecond resolution; its value is typically updated every 16ms), and is in many cases precise enough to measure the speed of code execution in algorithms.
Split into simpler sentences: It measures time in milliseconds, though it does not have millisecond precision: its value is typically updated every 16ms. In many cases, it's precise enough to measure the speed of code execution in algorithms.