Requests in Processing VS Request per Second

[surfman]

I found my Requests in Processing is far lower than Request/Second. is that ok? Requests in Processing is less than 20, but Request/Second is always more than 200, can I increase Requests in Processing?

there is option: Persistent Connection in lsphp settings. it is not available at default. will it increase performance if I turn it on? any potential trouble with it? thanks

by the way, where may I find tuning doc/tips? there are few docs in wiki. thanks.