[ovs-discuss] [OVS-DPDK] vhost-user with multiple queues does not work

[Felix Brucker]

Hi Ciara,

thanks that clarified it, i got confused by > Also this does NOT set the multiqueues the guest shall get
i read the Install md from here http://openvswitch.org/support/dist-docs/INSTALL.DPDK.md.txt
i thought this is related to the download on the same site (http://openvswitch.org/releases/openvswitch-2.5.0.tar.gz), but it seems not to.
With the n-dpdk-rxqs=2 option i was able to get 2 queues inside the vm and working communication, too.
After testing i will try to get the latest (post 2.5) version of ovs to get a more fine grained control over the queues.
Thanks all!

Best regards
Felix

-----Ursprüngliche Nachricht-----
Von: Loftus, Ciara [mailto:ciara.loftus at intel.com] 
Gesendet: Montag, 4. April 2016 18:11
An: Felix Brucker <FBrucker at xantaro.net>; Christian Ehrhardt <christian.ehrhardt at canonical.com>
Cc: Daniele Di Proietto <diproiettod at vmware.com>; discuss at openvswitch.org
Betreff: RE: [ovs-discuss] [OVS-DPDK] vhost-user with multiple queues does not work

> yes that part works, but for communication to work between the guest 
> and host OVS has to use 2 queues as well, which currently does not work.
> So how does one set multiple queues for vhostuser in OVS 2.5.0 or below?
> Im not talking about libvirt or qemu regarding the above question, but OVS.

Hi Felix,

As we've mentioned before, you need to use the following command:

ovs-vsctl set Open_vSwitch . other_config:n-dpdk-rxqs=2

... to assign two rx queues to the vhost-user ports in OVS.

This is clearly stated in INSTALL.DPDK.md on the 2.5 branch. I suspect you were previously looking at the latest INSTALL guide which pointed you to use the n_rxq option, which is not available on the older branch-2.5.

Essentially, if your bridge has two vhost-user ports eg. vhost-user-0 and vhost-user-1, the effect of ' ovs-vsctl set Open_vSwitch . other_config:n-dpdk-rxqs=2'
is the same as
ovs-vsctl set Interface vhost-user-0 options:n_rxq=2 ovs-vsctl set Interface vhost-user-1 options:n_rxq=2

On branch-2.5, you need to use the former command.

Thanks,
Ciara

> 
> Grüße
> Felix
> 
> Von: Christian Ehrhardt [mailto:christian.ehrhardt at canonical.com]
> Gesendet: Montag, 4. April 2016 17:35
> An: Felix Brucker <FBrucker at xantaro.net>
> Cc: Daniele Di Proietto <diproiettod at vmware.com>; Loftus, Ciara 
> <ciara.loftus at intel.com>; discuss at openvswitch.org
> Betreff: Re: [ovs-discuss] [OVS-DPDK] vhost-user with multiple queues 
> does not work
> 
> Hi Felix,
> here you already do the right thing:
> 
>     <interface type='vhostuser'>
> [...]
>       <driver queues='2'/>
> 
> Given you have the recent libvirt and qemu versions that translates to 
> the right qemu parameters as you have seen in my initial posts.
> 
> You can then log into the guest and check with "ethtool -l" if the 
> guest really "sees" its multiple queues (also shown in my first mail 
> that this fails for me)
> 
> Kind Regards,
> Christian