Last Updated on 2012-05-10.
After upgrading from Ubuntu 11.04 to 11.10 (guest VM which was running on Hyper-V, having the guest modules enabled like here), the network pings were suddenly very slow.
First I thought of maybe bad hv_* modules in the 11.10 version and put them on the blacklist, but that didn’t help.
The problem was, I had accidentally used the “old network adapter” in the Hyper-V manager instead of the default one.
With the default LAN adapter and the hv_* modules enabled, network speed was fine again.