does begin block effect any performance in modperl

[abhishek jain]

Hi friends,
i need to know that if i add the following block then will it affect
anything in the execution of modperl apart from first time run.

BEGIN{
require'abc.pl';
require'large_file.pl';

};

I mean anything relative to the performance.is the begin block called
everytime orjust the first time and is it safe to define a function in a
file and call it with this method rather than a package ,

Pl. help me.

Thanks,
Abhishek jain.