[ovs-discuss] ovs not triggering vxlan offload

Jesse Gross jesse at nicira.com
Fri Sep 11 03:05:22 UTC 2015


It actually is the same root cause. The only difference is the NIC is
not the same and the driver is reacting in a different way.

On Thu, Sep 10, 2015 at 7:53 PM, Xu (Simon) Chen <xchenum at gmail.com> wrote:
> I looked at that thread, and it's slightly different from mine...
>
> My traffic is flowing, just VXLAN offload isn't kicking in, which
> obviously has a significant performance hit. I am using a datapath
> kernel module built from OVS 2.4.0.
>
> On Thu, Sep 10, 2015 at 10:48 PM, Jesse Gross <jesse at nicira.com> wrote:
>> On Thu, Sep 10, 2015 at 7:36 PM, Xu (Simon) Chen <xchenum at gmail.com> wrote:
>>> Hello,
>>>
>>> I am testing OVS 2.4.0 on Linux 3.18 kernel.
>>>
>>> Not sure when it got changed, but VXLAN offload is no longer on by
>>> default in 3.18 - it used to be the case in 3.14. So, normally I have:
>>> ethtool -k eth4 | grep tnl
>>> tx-udp_tnl-segmentation: off [fixed]
>>>
>>> Configuring a VXLAN interface manually would trigger that option to
>>> turn on. Something like:
>>> ip link add vxlan0 type vxlan id 11 group 239.1.1.1 dev eth4
>>> ip addr add 1.2.4.5/24 dev vxlan0
>>> ip link set up vxlan0
>>>
>>> Then we have:
>>> ethtool -k eth4 | grep tnl
>>> tx-udp_tnl-segmentation: on [requested off]
>>>
>>> I imagined that when OVS created the VXLAN tunneled ports, it should
>>> turn on VXLAN offload as well, but it's not happening.
>>
>> This was reported just yesterday:
>> http://openvswitch.org/pipermail/discuss/2015-September/018714.html
>>
>> I'm assuming that this is with the out of tree OVS kernel module. In
>> that case, the change is in OVS 2.4 and shouldn't be a difference
>> between Linux 3.14 and 3.18.



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