What I really wanted to talk about is an application server that I wrote for PHP.  The problem I identified a while back is when I’m writing code in PHP the thing I’m doing most of the time is writing web applications. Now PHP is usually fast, at least that is, when you’re not writing huge sites that take a lot of requests. The way PHP is normally, historically, implemented is for every page request you have to build up and tear down your application, and with some SAPIs you have to also build up and tear down the PHP binary on top.

That presents a problem for performance, in that every time somebody requests a page you’re doing a lot of work to get the application to a state where it can start spitting out content – then at the end throwing away all that hard work you did. It wastes physical time and CPU cycles, not forgetting often IO and memory in the process. To resolve the issue you have to make your application persistent, which is something that PHP isn’t designed for in this context. Read the rest of this entry »