Finding bottle necks in PHP Code is way easier than you think, no microtime or even third party tools are required to get a proper profiling and insights about your code performance, just read on.

There are basically 3 simple steps how to get to a profiling of your application to get performance insights.

1. Step xdebug setup

Check if your installation has xdebug support enabled:

-bash-4.1$ php --info | grep -i xdebug | grep enabled
xdebug support => enabled

if that does not show anything then checkout the Manual

if it does not show enabled then checkout your php.ini and enable the extension.

2. Step create this bash alias

alias php-profile='php -d xdebug.profiler_enable=on -d xdebug.profiler_output_name=profile.out -d xdebug.profiler_output_dir=$PWD'

3. Step create a PHPUnit test case that exercise your code

this is pretty simple as this snipped will illustrate it on a DNA class with the method hammingDistance that is our bottle neck to be profiled:

// filename: DNATest.php

require_once __DIR__.'/DNA.php';

final class DNATest extends \PHPUnit\Framework\TestCase
{
    public function testNoDifferenceBetweenEmptyStrands()
    {
        $dna = new DNA('GGACT');
        $distance = $dna->hammingDistance(new DNA('CGACT'));
        $this->assertThat($distance, $this->equalTo(1));
    }
}

Finally run the profiling

run the profiling this way (assuming you have the phpunit.phar there): 

php-profile phpunit.phar DNATest.php

That will

  • run the test
  • produces a profile.out

That file contains all profiling data. It can be opened by PHPStorm or QCacheGrind.

However now you got a bunch of metrics, you need to first ignore all the profiling of PHPUnit and find the start of the invocation of your code.

What other approaches do you use to get profiling? Please share your experience.

Thanks for reading!