It depends on the size of your project of course… But if you don't want to reload and compile the scripts for every request, then you use APC as other commenter

It depends on the size of your project of course… But if you don't want to reload and compile the scripts for every request, then you use APC as other commenter posts here. My main problem with that way of PHP working is that you have to load again and again all the configuration, even if say your database is still on the same host:port. With a long running process, you'll just load that once. For me it always depends on the task at hand what tool you'll use.