Optimizing mod_perl

If you use Apache, you can preload some modules and speed up processing.

Preloading Perl Modules at Server Startup

You can use the PerlRequire and PerlModule directives to load commonly used modules such as CGI.pm, DBI and etc., when the server is started. On most systems, server children will be able to share the code space used by these modules. Just add the following directives into httpd.conf:

PerlModule CGI
PerlModule DBI

But an even better approach is to create a separate startup file (where you code in plain perl) and put there things like:

use DBI ();
use Carp ();

Don't forget to prevent importing of the symbols exported by default by the module you are going to preload, by placing empty parentheses () after a module's name. Unless you need some of these in the startup file, which is unlikely. This will save you a few more memory bits.

Then you require() this startup file in httpd.conf with the PerlRequire directive, placing it before the rest of the mod_perl configuration directives:

PerlRequire /path/to/start-up.pl

Please follow this link to read the full original article by Stas Beckman.