Open Stack

Hi,

My expertise on the subject is pretty much zero, but the performance loss
(which I think is throughput loss) is so blatant that perhaps there's more
than the MTU issue. From what Robert writes, GRO definitely plays a role
too.

My only suggestion would be to route the question to ovs-discuss in order
to get some help in precisely understanding what's going on.
In order to understand the relationship with GRO, what are the CPU usage
levels on the receiving node with and without GRO enabled?

Salvatore


On 22 January 2014 17:26, Rick Jones <rick.jones2 at hp.com> wrote:

> On 01/22/2014 03:01 AM, Robert Collins wrote:
>
>> I certainly think having the MTU set to the right value is important.
>> I wonder if there's a standard way we can signal the MTU (e.g. in the
>> virtio interface) other than DHCP. Not because DHCP is bad, but
>> because that would work with statically injected network configs as
>> well.
>>
>
> Can LLDP be used here somehow?  It might require "stretching"  things a
> bit - not all LLDP agents seem to include the information, and it might
> require some sort of "cascade."  It would also require the VM to pay
> attention to the frames as they arrive, but in broad, hand-waving, blue-sky
> theory it could communicate maximum frame size information within the
> broadcast domain.
>
> rick
>
>
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