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

[Hans van Kranenburg]

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.

# ethtool -K ovs0.31 tx off
# ethtool -k ovs0.31
Offload parameters for ovs0.31:
rx-checksumming: off
tx-checksumming: off
scatter-gather: off
tcp-segmentation-offload: off
udp-fragmentation-offload: off
generic-segmentation-offload: on
generic-receive-offload: off
large-receive-offload: off
ntuple-filters: off
receive-hashing: off

-- 
Hans van Kranenburg - System / Network Engineer
+31 (0)10 2760434 | hans.van.kranenburg at mendix.com | www.mendix.com