private static boolean similar(double r1, double r2, double threshold) {
        return Math.abs(r1 - r2) / (( r1 + r2) / 2) < threshold;
    }
Returns true if it is worthwhile to make the given resource change, false if it is too insignificant
node-repository/src/main/java/com/yahoo/vespa/hosted/provision/autoscale/Autoscaler.java