package My::Class;
our @ISA=qw(Base::Class);
my %obj;

sub new {
    ...
    my $h=$class->SUPER::new;
    
    $obj{$h}{host}=shift;
    $obj{$h}{port}=shift;
    ...
}

sub DESTROY {
    my $h=shift;
    delete $obj{$h};
    $h->SUPER::DESTROY;
}