Measure CPU Time / User / System Time in PHP Scripts

measure_cpu_time.php

<?php

$measure = function (callable $lambda) {
    
    $rUsage = getrusage();
    $startUTime = $rUsage['ru_utime.tv_usec'] + $rUsage['ru_utime.tv_sec'] * 1000000;
    $startSTime = $rUsage['ru_stime.tv_usec'] + $rUsage['ru_stime.tv_sec'] * 1000000;
    $startHrTime = hrtime(true);

    $lambda();
    
    $total  = (hrtime(true) - $startHrTime) / 1000000;
    $rUsage = getrusage();
    $user   = ($rUsage['ru_utime.tv_usec'] + $rUsage['ru_utime.tv_sec'] * 1000000 - $startUTime) / 1000;
    $system = ($rUsage['ru_stime.tv_usec'] + $rUsage['ru_stime.tv_sec'] * 1000000 - $startSTime) / 1000;
    $wait   = $total - ($user + $system);

    $measurements = [
        'user'   => $user,
        'system' => $system,
        'wait'   => $wait,
        'total'  => $total,
    ];
    
    $format = function (float $timeInMs) {
        return str_pad(number_format($timeInMs, 0, ',', '.') . ' ms', 10, ' ', STR_PAD_LEFT);
    };

    foreach ($measurements as $header => $value) {
        echo "${header}:\t" . $format($value) . PHP_EOL;
    }
    echo PHP_EOL;
};

echo "Factorial\n";
$measure(function () {
    (function ($_) {
        $factorial = 1;
        for ($i = 1; $i <= $_; $i++) {
            $factorial = $factorial * $i;
        }

        return $factorial;
    })(120000000);
});

echo "usleep()\n";
$measure(function () {
    usleep(500000);
});

echo "remote http call\n";
$measure(function () {
    file_get_contents('https://httpbin.org/delay/1');
});

echo "radom_bytes()\n";
$measure(function () {
    foreach (range(0, 100000) as $_) {
        random_bytes(1024);
    }
});

$ php  measure_cpu_time.php
Factorial
user:	  1.335 ms
system:	      0 ms
wait:	      2 ms
total:	  1.337 ms

usleep()
user:	      0 ms
system:	      0 ms
wait:	    500 ms
total:	    500 ms

remote http call
user:	     22 ms
system:	     13 ms
wait:	  1.649 ms
total:	  1.684 ms

radom_bytes()
user:	     39 ms
system:	    550 ms
wait:	      1 ms
total:	    590 ms