Each piece of the source code is run using php CLI 100 times. 50% slowest results are then discarded, average and standard deviation calculated. The average is then used to compare speed difference between two functions. Test are done on variety of hardware/software and then averaged for the final score. All test are executed on the physical machines.
Currently only PHP packaged for Debian and Ubuntu is used. Test will be re-run whenever new version of PHP is released and packaged.
Please feel free to add new tests. I'm reviewing them before they are run so either be patient or drop me an email at nexor1984 gmail com with the reminder to add run your test!