/* How many times the code under test should run in each function */
define('LOOP',1000000);
 
function f1() {
  for($i=0; $i<LOOP; ++$i) {
    @file_exists('/etc/apasswd');
  }
}
function f2() {
  for($i=0; $i<LOOP; ++$i) {
    @is_file('/etc/apasswd');
  }
}
$start = microtime(true);
f1();
$stop = microtime(true);
$time1 = $stop - $start;
 
$start = microtime(true);
f2();
$stop = microtime(true);
$time2 = $stop - $start;
 
echo $time1 . "\t";
echo $time2 . "\n";