Symfony routing is a powerful tool to manage urls and actions mappings. When routes are loaded, many actions are performed :
These steps are performed on every requests in 'dev' environment, so if routing files do not change, these can be really time consuming. There are other side effects :
Solution : set the debug parameter to 'false'
edit your factories.yml
all: routing: class: sfPatternRouting param: debug: false
of course don't forget to clear the cache every time the routing.yml is updated ...