The Stopwatch component provides a way to profile code.
$ composer require symfony/stopwatch
use Symfony\Component\Stopwatch\Stopwatch;
$stopwatch = new Stopwatch();
// optionally group events into sections (e.g. phases of the execution)
$stopwatch->openSection();
// starts event named 'eventName'
$stopwatch->start('eventName');
// ... run your code here
// optionally, start a new "lap" time
$stopwatch->lap('foo');
// ... run your code here
$event = $stopwatch->stop('eventName');
$stopwatch->stopSection('phase_1');