Re: [Qemu-devel] wiki: update missing info on "Enabling multi-queue" section of vhost-user

[Marcel Apfelbaum <marcel@redhat.com>]

On 03/21/2016 12:10 PM, Lin Ma wrote:
> Hi Marcel,
> I found that the information on "Enabling multi-queue" in http://wiki.qemu.org/Features/vhost-user-ovs-dpdk
> are inaccurate.
> In ovs 2.5 or older, The option 'other_config:n-dpdk-rxqs' is used and there is no options:n_rxq.
> The n_rxq is available since post 2.5.0.
> But when setup an interface's option using ovs-vsctl, It doesn't check whether the option is valid or not.
> So if a user follows the instruction of above wiki page to setup the vhost-user multi queues in ovs 2.5-,
> The user wont get any error information but the vms which have vhost-user multi queues nics dont work and the user
> gets confused.
> I think that we should mentioned on wiki:
> In ovs 2.5 or older version: The usage is:
> ......
> ovs-vsctl set Open_vSwitch . other_config:n-dpdk-rxqs=<queues_nr, the same as QEMU>
> //BTW: It only supports setting up same number of rx queues for all of PMD netdevs.
> ......
> In post ovs 2.5, The usage is:
> ......
> ovs-vsctl set Interface vhost-user1 options:n_rxq=<queues_nr, the same as QEMU>
> ovs-vsctl set Interface vhost-user2 options:n_rxq=<queues_nr, the same as QEMU>
> ......
> Moreover, For vhost-user live migration support, Because qemu needs vhost-user backend providing
> VHOST_USER_PROTOCOL_F_LOG_SHMFD feature bit since commit 1be0ac2.
> The dpdk commit d639996 provides this feature bit but it isn't available in dpdk 2.2.0, It may be merged into 2.3.0.
> In this case, If a user uses qemu 2.5+dpdk 2.2+ovs, The vhost-user live migration wont succeed.
> Should it be mentioned on wiki as well? I dont have permissions to update wiki pages, So sending the information to list.
> Lin

Hi Lin,

Thank you for the important update, would you want update the wiki yourself?
If you have the time, please reply me on a private thread with the desired username
and I'll supply a temporary password.

Thanks,
Marcel