Manual:$wgEnableProfileInfo/en

Details
Controls the availability of $profileinfo, which shows profiling data.

If set to true, profiling data will be stored in the $profiling table inside the database. If you want to log profiling data, enable $code in your StartProfiler.php and run $update to create the profiling table. You can also set $Profiler to a different value in order to store/display profiling data differently. See for more information!