You need to read the manual. Just installing mod_perl on your web server isn't enough to have your scripts be cached (and accelerated) by it.

You have to have some way of telling your webserver that you want a script to be cached by mod_perl. This is set in your httpd.conf file (assuming apache), either by mapping files in a certain location, or files with a certain extension, to be handled by a mod_perl handler. (Usually Apache::Registry, unless you write your own. I don't, usually.)

8.8 requests/sec doesn't sound like your CGIs are being handled by mod_perl at all. Some very expensive scripts, processor-wise, I've written that use mod_perl run in the 140 to 160 requests/sec range, and 10-11 requests/sec not under mod_perl.

There are other issues around mod_perl usage. Basically, you need clean code, lexically scoped and without globals. Read the docs I pointed you at above and you'll learn quite a bit.

Stick with it! mod_perl is excellent! Here's a node I started a little while ago when I was just learning mod_perl. You can learn a lot in a few months!