[ovs-discuss] Simple test-setup: lots of TCP Retransmission, TCP Dup ACK

[Jesse Gross]

On Thu, Jan 5, 2012 at 3:15 AM, Hans van Kranenburg
<hans.van.kranenburg at mendix.com> wrote:
> On 01/05/2012 04:04 AM, Jesse Gross wrote:
>>
>> On Wed, Jan 4, 2012 at 8:32 AM, Hans van Kranenburg
>> <hans.van.kranenburg at mendix.com>  wrote:
>>>
>>> Any idea?
>>>
>>> delta.mgt.kantoor.mendix.nl:~ 0-# ethtool -k eth0
>>> Offload parameters for eth0:
>>> rx-checksumming: on
>>> tx-checksumming: on
>>> scatter-gather: on
>>> tcp-segmentation-offload: off
>>> udp-fragmentation-offload: off
>>> generic-segmentation-offload: on
>>> generic-receive-offload: on
>>> large-receive-offload: off
>>> ntuple-filters: off
>>> receive-hashing: off
>>
>>
>> What happens if you turn off tx checksum offloading on the interfaces
>> with IP addresses assigned to them?
>
>
> Yay! Knowing this, and looking at the list archives again... it seems to be
> a rather common issue.

I'm guessing that it's the combination of offloading, vlans, and your
driver/kernel version so if you can move to a new kernel (like 3.1)
that may solve the issue.