[php] Accurate way to measure execution times of php scripts

You have the right idea, except a more precise timing is available with the microtime() function.

If what is inside the loop is fast, it is possible that the apparent elapsed time will be zero. If so, wrap another loop around the code and call it repeatedly. Be sure to divide the difference by the number of iterations to get a per-once time. I have profiled code which required 10,000,000 iterations to get consistent, reliable timing results.