Install xdebug and enable profiling

Installing xDebug and enabling profiling is a two step process which is outlined below.

First of all you’ll need to install the xDebug library

sudo apt-get install php5-xdebug

sudo apt-get install php-xdebug

If the package was installed successfully, you should see ‘xdebug’ listed when you run:

Then you’ll need to configure xDebug to enable profiling

Profiling isn’t enabled by default, so the next step is to enable it via the config file. You can find the file at:

/etc/php/YOUR_VERSION/apache2/conf.d/20-xdebug.ini

/etc/php/YOUR_VERSION/fpm/conf.d/20-xdebug.ini

Once you’ve found the file, append the following lines:

xdebug.profiler_append = 1
xdebug.profiler_enable = 0
xdebug.profiler_enable_trigger = 1

Restart the server to enable the changes

To enable the config changes, you’ll need to restart your server

Apache

First check that the new config isn’t going to break anything:

sudo apache2ctl configtest

And then, if all is well, restart the server:

sudo service apache2 restart

Nginx

First check that the new config isn’t going to break anything:

sudo nginx -t

And then, if all is well, restart the server:

sudo service nginx restart

Ready to profile

You’re now ready to profile your PHP applications. It’s important to note with ‘profileenabletrigger’ enabled, you need to explicitly request profiling. You can do so by appending the following variable to your query-string:

?XDEBUG_PROFILE=1

Upon doing so, profiling data will be dumped to the /tmp folder on your server. You can then use KCacheGrind to parse and visualize the dump.