i was able to improve it by using this :

sub readxml{
$xmlfile = shift;
my $twig= new XML::Twig( 
                         twig_handlers      => 
                             { '_all_' => \&fall },  
                       ); 

$twig->parsefile($xmlfile);

}

sub fall{
    my( $twig, $element)= @_;
    if (!$element->{att}->{USE} || $element->{att}->{USE} !~ /EDV/){
        if ($element->name =~ /fk....\b/){
            my $key = substr($element->name,2,4);
            $data{xml}{$key}++;
        }
    }
}
[download]

but it still takes ~80 seconds...