Re: [PATCH 0/9][RFC] KVM virtio_net performance

Avi Kivity
2008-07-27T07:52:13Z

Bill Davidsen wrote:
> Anthony Liguori wrote:
>> Hi Mark,
>>
>> Mark McLoughlin wrote:
>>> Hey,
>>> Here's a bunch of patches attempting to improve the performance
>>> of virtio_net. This is more an RFC rather than a patch submission
>>> since, as can be seen below, not all patches actually improve the
>>> perfomance measurably.
>>>
>>
>> I'm still seeing the same problem I saw with my patch series.
>> Namely, dhclient fails to get a DHCP address. Rusty noticed that RX
>> has a lot more packets received then it should so we're suspicious
>> that we're getting packet corruption.
>
> I have been discussing this (on this list) in another thread. Putting
> tcpdump on the eth0 device in the VM, the br0 device in the host, and
> the eth0 (physical NIC) in the host, you can see that when the VM
> generates a DHCP request it shows up on the br0 in the host, but never
> gets sent on the wire by eth0.
>
> That's the point of failure, at least using RHEL5/FC6/kvm-66 as the
> environment.

Does playing with the bridge forward delay ('brctl setfd') help?

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