No, Ruby behaves like APC by default; code is loaded and parsed once per process, and then the AST is reused from memory. You can do some stuff to hot reload from disk (ie, Rails' reloader), but you have to intentionally do it.

This would just improve the time to initially start a Ruby process.

PHP needs an opcache because its standard behaviour is to discard all state after each request - including all compiled bytecode - kind of emulating the CGI model.

Ruby web apps on the other hand tend to be run in a loop - the script never exits after a request, it just goes back to the top of the loop to accept the next request to serve.

e.g. https://github.com/rack/rack/blob/master/lib/rack/handler/fa...

        FCGI.each { |request|
          serve request, app
        }

It's nice because it completely decouples your app's startup time from request processing time, so you can do expensive setup stuff up-front without slowing down each request. The disadvantage to that is there's not much pressure to keep startup time low, since it's only happening once.