I think that is at least enough data to claim this issue verified. @Jon, you could check whether you have the same issue by looking at dmesg and ifconfig output on the sender side. If you see the "rides the rocket" messages together with an incrementing tx drop count, that is this bug. And it should be going away even without disabling sg when using the proposed kernel for the sender.
And though it probably should not cause that bad effects, but on the other hand higher layer applications can expect the tcp layer to correct dropped packets. Which maybe is done but possibly ending up (by trying to avoid copying data in memory) with the same (or similar) fragmented send buffer. And in the end all re-tries are dropped. ** Tags removed: verification-needed-trusty ** Tags added: verification-done-trusty ** Tags added: verification-done-utopic ** Changed in: linux (Ubuntu) Assignee: Stefan Bader (smb) => (unassigned) -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1317811 Title: Dropped packets on EC2, "xen_netfront: xennet: skb rides the rocket: x slots" To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1317811/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs