You could use a directory tree to hold your data, and then have a little thing like this to log your module usage:

# plugh.pl
my @module = caller;
my @program = caller(1);
open X, '>', "/module/logger/base/path/$module[1]/$program[1]" 
  or die "Can't log module $module[1] use by program $program[1]\nReas
+on: $!\n";
print X time(), "\n"; # content doesn't really matter... whatever you 
+like
close X;
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Then your modules need only do something like:

# MyModule
 . . .
require "plugh.pl";
 . . .
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Obviously, if you want to use this, you'll have to do a little setup & such. The reason I proposed it is that you don't need to rely on any modules since the OS would provide your "database". You could even use find to do your reporting...

...roboticus

Yes, it's small and crufty--but simple, too....