Kwik-e-marK is a very simple and easy-to-use benchmark class that lets you test the execution time of your php script. It's very easy to split the code into many parts, which can be marked green or red in the report as a reminder (optimized or not) and even excluded from the total execution time. This tool can both output a simple total execution time or a complete report with comments for every code portion, in a popup that includes a button for script re-execution. Under unix system, the script also outputs the memory used. Visit the official web site for the online user guide.