sub arg2 {
	my($str,$lvl)= @_;
	my $str1 = $str;
	return $str if !$lvl;
	# skip up to and including nth ( paren, then strip n ) parens from end
	$str =~ /([^(]*\(){$lvl}(.+)(\)){$lvl}/;

	return $2 unless $lvl == -1;
	$str =~ /\(([^\(\)]+)\)+/;
	return $1;

}

##</code><code>##

                Rate get_proparg        arg2
get_proparg 137195/s          --        -31%
arg2        199115/s         45%          --