Vigorous nods!

It might be interesting to note that I worked with a very large bookstore chain that to this day (as far as I know...) still uses “plain ol’ CGI” to do everything.   And it works just fine.

I suggest also that you should thoroughly consider your options.   I am not a huge fan of mod_perl, preferring the “FastCGI” approach (and other distributed-processing techniques) for a variety of reasons.   (However, it is not my purpose to start any sort of religious war on that point.)   At this juncture, consider carefully why your app is not giving you the performance that you require, in its present configuration.   Seriously consider the now-viable option of, “throw silicon at it.”   Conversion of a web app to a fundamentally different form of running, as you now contemplate, is no trivial undertaking and has no guarantee of stable success.