time（）以及PHP如何解析脚本

I put $START_TIME = time(); at the beginning of my code, and $END_TIME = time(); at the end of my code. then I did echo ($END_TIME - $START_TIME); and received a difference of ~ 4.

My question is, how inaccurate is this way of measuring parsing/processing time? and why?

edit: i took out the stupid part of my question :) the rest of the question still stands!

time() is giving you the seconds since the "unix big bang". What you want is microtime(true) (see documentation here) which gives you the microseconds.