Busting “echo is faster than print”

AHSauge — Wed, 05 Nov 2008 23:17:09 +0000

I’ve previously been talking about premature optimization. Today I thought I should illustrate how ridicules some of the stuff is by busting “echo is faster than print”. There’s a lot of people calming that this is true (1, 2, 3, 4 and a lot of others). Now to be clear, they are somewhat right about this. Echo is really faster than print, which it really should due to the fact that echo don’t return anything while print does. The problem and my point here however, is how much this difference really is. The answer is so tiny that you can forget actually measuring it in a real world application. There’s why:
First off, the code I’ve been using is


$res = array_fill(0, 5, 0);
for($i = 0; $i < 5; $i++)
{
    ob_start();
    $start = microtime(true);
    for ($j = 0; $j < 1000000; $j++)
        echo ".";
    $end = microtime(true);
    $res[$i] = $end-$start;
    ob_end_clean();
}
for ($i = 0; $i < 5; $i++)
    echo $res[$i]."\n";
?>

and


$res = array_fill(0, 5, 0);
for($i = 0; $i < 5; $i++)
{
    ob_start();
    $start = microtime(true);
    for ($j = 0; $j < 1000000; $j++)
        print ".";
    $end = microtime(true);
    $res[$i] = $end-$start;
    ob_end_clean();
}
 
for ($i = 0; $i < 5; $i++)
    echo $res[$i]."\n";
?>

As you can see I’ve tried to make this as simple as possible. I’ve used output buffer to remove the huge variables also known as browser and network (yes, they’re really a bottleneck here, trust me or try comparing firefox with lynx). Testing was done in the 64bit version of Fedora 9 (which is a linux distro) with PHP 5.2.6 on an AMD Athlon 64 X2 4600 (dual core CPU running at standard 2.4GHz).

Running this gives me an average of 0.333 seconds for echo and 0.346 seconds for print. Doing some calculation you’ll see that the average difference between each echo and print is 13ns or 0.000000013 seconds. Even though this is a 3.8% difference, it’s not even a millionth of a second, but 13 billionth! Hardly any difference if you ask me. I know, it’s just testing with a single, silly punctuation mark. To prevent people from going “There must be a bigger difference with a longer string!”, I ran the test with the first paragraph of lorem ipsum.

Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Nunc luctus arcu vehicula est. Donec facilisis iaculis magna. Mauris neque dui, varius in, fermentum id, scelerisque et, massa. Nam ac velit nec odio molestie pellentesque. Nulla dolor mauris, tempus ultrices, cursus in, ultrices sollicitudin, orci. Sed at ligula. Sed id erat id nisl molestie tempus. Vestibulum nibh dolor, vulputate nec, dictum non, sollicitudin nec, nibh. Sed vitae diam eget felis dignissim tempor. Aenean vel risus. Integer consectetuer nibh. Ut eu nunc. Donec at sapien.

This is 551 characters, which should satisfy most people. Results? 0.987 seconds for echo and 1.014 seconds for print, meaning echo is 2.6% faster. Again, hardly any difference as this is 27ns or 0.000000027 seconds. Conclusion: Myth busted! You’ll have to do a ridicules amount of outputing to make any actual difference.

PS: If you run this on your own computer, I would love to hear about your results (including type of CPU, OS and PHP version). Remember this though: Please bar in mind that you’ll have to disable any CPU-throttling and run it in separate files to get accurate results.

var/log » echo vs print

Busting “echo is faster than print”