The main (and only at the moment) use case for the Routing::toString() function is to print a representation of the routing table in a log message. The function is implemented using an std::stringstream, and the returned std::string is then inserted into an std::ostream. This is inefficient. Replace the function with a specialization of the operator<<() and use it in the caller. Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Reviewed-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com> Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>