PHP Large Array Sum Micro Benchmark

bench.php

<?php
declare(strict_types=1);

printf("Current PHP version: %s\n", phpversion());

$iterations = (int)($_SERVER['argv'][1] ?? 2000);
printf("Bench iterations: %d\n", $iterations);

$time = microtime(true);
//$input = array_map('intval', str_split(str_repeat(trim(file_get_contents('input.txt')), 100)));
$input = array_fill(0, 65000, 1);
printf("Loading input took %0.3fs\n", microtime(true) - $time);

printf("(repeated) input length: %d\n", count($input));

$time = microtime(true);
$sum = 0;
for($i=0; $i < $iterations; $i++) {
    $sum += array_sum($input);
}
printf("array_sum took %0.3fs\n", microtime(true) - $time);

$time = microtime(true);
$sum = 0;
for($i=0; $i < $iterations; $i++) {
    foreach($input as $digit) {
        $sum += $digit;
    }
}
printf("foreach +digit took %0.3fs\n", microtime(true) - $time);

$rangeMin = $rangeLength = 16250; // 1/4 of input length
$rangeMax = $rangeMin + $rangeLength;

$time = microtime(true);
$sum = 0;
for($i=0; $i < $iterations; $i++) {
    $sum += array_sum(array_slice($input, $rangeMin, $rangeLength));
}
printf("array_sum+array_slice took %0.3fs\n", microtime(true) - $time);

$time = microtime(true);
$sum = 0;
for($i=0; $i < $iterations; $i++) {
    for ($j=$rangeMin; $j < $rangeMax; $j++){
        $sum += $digit;
    }
}
printf("for +digit took %0.3fs\n", microtime(true) - $time);

result.txt

$php bench.php 5000
Current PHP version: 7.4.0
Bench iterations: 5000
Loading input took 0.007s
(repeated) input length: 65000
array_sum took 3.230s
foreach +digit took 9.022s
array_sum+array_slice took 1.245s
for +digit took 2.729s