These graphs compare the initial values from the 2011-12-15 kernel (blue) to the current IPv4 (red) and IPv6 (green) values of 2012-04-08 showing improvements.
The first four values are the old and new values for IPv4 UDP with the sysctl to control checksumming turned off. As expected these values have not signifigcantly changed.
The next four values values are IPv4 the same tests just with the sysctl turned on. Again the two values with and without offloading have not significantly changed.
The last four values are the old and new IPv6 values, with and without offloading support. As you can see, the situation has been improved in both cases but performance is still behind IPv4. These cases need further investigation, especially given we are able to send more UDP packets on IPv6 than on IPv4 now as can be seen in the PPS results. It might be wise to use a second test tool, given netperf had initially needed a patch to even work with IPv6/UDP.