[ovs-discuss] performance drop 60% when using vxlan tunnel

[Jesse Gross]

On Wed, Nov 5, 2014 at 10:58 PM, FengYu LeiDian
<fengyuleidian0615 at gmail.com> wrote:
> 于 2014年11月06日 00:08, Jesse Gross 写道:
>
>> On Tue, Nov 4, 2014 at 11:03 PM, FengYu LeiDian
>> <fengyuleidian0615 at gmail.com> wrote:
>>>
>>> Hi
>>>
>>> Env: redhat 6.4, OpenvSwitch-2.1.2, using native
>>> datapath/linux/openvswitch.ko module
>>>
>>> VM1 on host1, VM2 on host2, host1 and host2 are connected by a switch.
>>> both VM enable virtio/vhost when launching VM
>>>
>>> case1:
>>> VM -> tap -> ovs-bridge -> eth1
>>>
>>> case2:
>>> VM -> tap -> ovs-bridge -> vxlan -> eth1
>>>
>>> When using vxlan in case2, iperf performance drop 60%,
>>
>>
>> Your NIC probably doesn't support offloads (checksum, TSO, etc.) in
>> the presence of VXLAN.
>
>
> This is the default features supported by my NIC 82599 both in case1 and
> case2.

I can assure you that this NIC does not support VXLAN and the stack is
being forced to do segmentation in software.