Start and stop a timer PHP

Question

I need some information regarding starting and stopping a timer in PHP. I need to measure the elapsed time from the start of my .exe program (I\'m using exec()

Answer 1

Since PHP 7.3 the hrtime function should be used for any timing.

$start = hrtime(true);
// execute...
$end = hrtime(true);   

echo ($end - $start);                // Nanoseconds
echo ($end - $start) / 1000000000;   // Seconds

The mentioned microtime function relies on the system clock. Which can be modified e.g. by the ntpd program on ubuntu or just the sysadmin.