[ovs-discuss] network bandwidth in Openstack when using OVS+VLAN

[Gurucharan Shetty]

There could be multiple reasons for the low throughput. I would probably
look at the following.

* Is the VM ethernet driver a para-virtual driver? Para-virtual drivers
give a good performance boost.
* Is TSO ON in the VM and the Hypervisor?
* What throughput do you get while using Linux bridge instead of OVS?
* Are you using tunnels? If you are using a tunnel like GRE, you will see a
throughput drop.



On Mon, Jul 29, 2013 at 1:48 AM, Li, Chen <chen.li at intel.com> wrote:

>  Hi list,****
>
> ** **
>
> I’m a new user to OVS.****
>
> ** **
>
> I installed OpenStack Grizzly, and  using Quantum + OVS + VLAN for network.
> ****
>
> ** **
>
> I have two compute nodes with 10 Gb NICs, and the bandwidth between them
> is about  *8.49* Gbits/sec (tested by iperf).****
>
> ** **
>
> I started one instance at each compute node:****
>
> instance-a => compute1****
>
> instance-b=> compute2****
>
> The bandwidth between this two virtual machine is only *1.18* Gbits/sec.
>
 **
>
> Then I start 6 instances at each compute node:****
>
>           (   instance-a => compute1 ) ----- iperf------ > (instance-b=>
> compute2)****
>
>                           (   instance-c => compute1 ) ----- iperf------ >
> (instance-d=> compute2)****
>
>                           (   instance-e => compute1 ) ----- iperf------ >
> (instance-f=> compute2)****
>
>                           (   instance-g => compute1 ) ----- iperf------ >
> (instance-h=> compute2)****
>
>                           (   instance-i => compute1 ) ----- iperf------ >
> (instance-j=> compute2)****
>
>                           (   instance-k => compute1 ) ----- iperf------ >
> (instance-l=> compute2)****
>
> The total bandwidth is only *4.25 *Gbits/sec.****
>
> ** **
>
> ** **
>
> Anyone know why the performance is this low ?****
>
> ** **
>
> Thanks.****
>
> -chen****
>
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