perftest-undefineds.php

<?php
error_reporting(E_NONE);

$cnt = 100;
$t1 = microtime(true);
$a = 4;
for ($i=1; $i<=$cnt; $i++) { if ($a) { 1+1; } }
$t2 = microtime(true);
unset($a);
for ($i=1; $i<=$cnt; $i++) { if ($a) { 1+1; } }
$t3 = microtime(true);
$a = array(1, 2, 3);
for ($i=1; $i<=$cnt; $i++) { if ($a[2]) { 1+1; } }
$t4 = microtime(true);
unset($a[2]);
for ($i=1; $i<=$cnt; $i++) { if ($a[2]) { 1+1; } }
$t5 = microtime(true);

$time1=$t2-$t1;
$time2=$t3-$t2;
$time3=$t4-$t3;
$time4=$t5-$t4;

printf("Test run 1    : %1.3f ms\n", $time1*1000);
printf("Test run 2    : %1.3f ms\n", $time2*1000);
printf("Test run 3    : %1.3f ms\n", $time3*1000);
printf("Test run 4    : %1.3f ms\n", $time4*1000);