Are you are benchmarking Apache on the first run of the mod_perl program? It only gets faster the second time the program is run by a particular http daemon. If you have many http daemons running, you will have to do many requests before you notice your program suddenly running faster.

Also, you might try reducing the number of print statements in your code. I think that perl's IO system has changed somewhat since I wrote Re: Speeding up commercial Web applications, but I think that the advice there is still good.

There are a few other optimizations that can improve print statements, but the improvements are small. Things to experiment with are:

• Eliminate string interpolation. This is about a 1% improvement in my version of perl.
• Use commas to separate print arguments instead of concatenating them as strings with the . operator.

Another mod_perl optimization is to move as much computation as possible to a BEGIN {} block, so it is only computed during the first run of your code. Similarly, put cleanup code in an END {} block.

It is easy to get confusing answers when profiling mod_perl. I use Time::HiRes and print the profiling information to STDERR. This is tedious but I suspect that the more deluxe profiling modules were not written with mod_perl in mind!

The ultimate test is load testing, which I do with a bunch of lwp GET requests running at the same time. With this I discover other Apache parameters to tune, such as the number of requests to service before restarting the http daemon. These server restarts require perl to reload the modules.