13.8 time( ) System Call Versus $r->request_time

If you need to know the time at which the request started, you can either install PerlPostReadRequestHandler, which adjusts the special Perl variable $^T to store that time:

$^T = time( );

and subsequently use that variable in the code, or you can use $r->request_time, which stores the exact request's start time and saves the extra system call to time( ).