With the introduction of the XML and YAML configuration files, you might have became a bit sceptic about the performance of the container itself. Even if services are lazy loading, reading a bunch of XML or YAML files on each request and creating objects by using introspection is probably not very efficient in PHP. [...] How can you have the best of both world? That's quite simply. The Symfony Dependency Injection component provides yet another built-in dumper: a PHP dumper.

The dumper lets you convert the service container into regular PHP code (expanding the container's functionality out into a Container class based on the XML/YAML configuration.