PHP 5.3 is quicker than PHP 5.2

I know that everyone already knows this, but I happened to find out for myself recently!

I was looking at the way view helpers work in ZF2 and thought it would be more convenient if we altered the syntax a little. A side-effect of the change was that we’d have to use call_user_func_array, which is perceived as slow. I thought I’d whip up a simple test to find out how much slower it would be over a direct method call.

That is, how much slower is this code:
$a = new A();
call_user_func_array(array($a, 'b'), array(1));
than this code:
$a = new A();
$a->b(1);

Bear in mind that I don’t do formal benchmarks and have no clue on methodology. Paul Jones is your man for proper testing of performance.

With that caveat out of the way this is the code I wrote to test:

benchmark.php

<?php

class A
{
function b($a)
{
return;
}
}

define ('ITERATIONS', 10000000);
$start = microtime(true);
$a = new A();
for ($i = 0; $i < ITERATIONS; ++$i) {
$a->b(1);
}
$stop = microtime(true);
echo 'Direct method call: ' . ($stop - $start) . ' seconds' . PHP_EOL;

$start = microtime(true);
for ($i = 0; $i < ITERATIONS; ++$i) {
call_user_func_array(array($a, 'b'), array(1));
}
$stop = microtime(true);
echo 'call_user_func_array call: ' . ($stop - $start) . ' seconds' . PHP_EOL;

This was the simplest possible scenario I could imagine and so would show call_user_func_array in the best possible light.

I ran the test on my laptop (using the command line) and got these results:


Direct method call: 21.155211925507 seconds
call_user_func_array call: 72.147792100906 seconds


i.e. call_user_func_array is around 3.5 times slower over 10 million iterations.

Nobody uses their laptop to serve a website though! Being the curious sort, I thought I’d test the difference of this script between PHP 5.2 and PHP 5.3 in a completely unscientific way as I’m lazy! I happen to have a server with both PHP 5.2 and PHP 5.3. on it, so I used that:

PHP 5.2:

Direct method call: 8.3424661159515 seconds
call_user_func_array call: 26.904649972916 seconds


PHP 5.3:

Direct method call: 3.35181903839 seconds
call_user_func_array call: 11.5989868641 seconds


As you can see, my server is much faster than my laptop :) Also, the relative difference is the same. i.e. PHP 5.3’s call_user_func_array is as slow as it is in PHP 5.2.

I think I’ll move everything to PHP 5.3 for the free performance gain! Of course, The question remains as to whether we should avoid call_user_func_array or not.

I would however recommend testing your own apps and see if it makes any difference and please don’t take this post as anything other than something interesting I found out!