You are being fooled by DProf. Your program is not actually spending 20% of its time in Exporter. I can't explain why it gets reported this way, but I have seen this before and am very confident that the reported time is not correct.

There are other reasons you might want to get ride of Exporter. The easiest way to do it is to simply use fully-qualified variable and sub names, like $My::Module::Variable.