High Performance PHP

<?php
if(file_exists("/cache/first.cache")) {
    $stat = @stat("/cache/first.cache");
    if ($stat[9] && (time() > $stat[9] + 10)) {
        unlink("/cache/first.cache");
    } else {
        include("/cache/first.cache");
        return;
    }
}

$cachefp = fopen("/cache/first.cache", "w");
ob_start();
?>
<html>
<body>
<!-- Cacheable for a 10 sec period -->
Today is <?= strftime("%A, %B %e %Y %H:%M:%S") ?> 
</body>
</html>
<?php
if ($cachefp) {
    $file = ob_get_contents();
    fwrite($cachefp, $file);
    ob_end_flush();
}
?>