You don't need to parse the grammar for every request and as they admitted it was an old implementation. What I understand they have a new one now. You can par

You don't need to parse the grammar for every request and as they admitted it was an old implementation. What I understand they have a new one now. You can parse grammar on save and make an optimized compiled format where static content is already resolved. Next step is to substitute semi-static content (like author name) to a runtime format, this last format can handle dynamic data substitution like current date & time, but probably going to be rare that any substitution is needed for the runtime format (how much truly dynamic data does a wiki have?), most of the time just print it with readfile or similar. Only difficult part here is cache invalidation for the runtime format (I know, it is one of the three difficult things you can do in programming). 3000 request/second in PHP is not hard, especially if you plan for it.