[ovs-discuss] vhost-user multiqueue PMD RSS

Darrell Ball dball at vmware.com
Mon Jun 12 01:19:59 UTC 2017

Try not to drop the list

In the general case, including the specific case that you mention, today’s design
is to select a queue from the tx port queues starting from low ID, that has the
least contending PMD threads.

From: Hui Jing <h.jingict at gmail.com>
Date: Sunday, June 11, 2017 at 2:33 PM
To: Darrell Ball <dball at vmware.com>
Subject: Re: [ovs-discuss] vhost-user multiqueue PMD RSS

Hi Darrell Ball,

Thanks for your reply with the link. Actually, my question comes from there when I was reading the article. In the article, Everything makes perfect sense when it says each PMD handle a single queue of the NIC. I am wondering what if one PMD thread is responsible for more queues (which is possible) of the VNIC, or in other words, number of  PMD threads is less than the number of queues of  vhost-user. In this case, how the PMD distribute traffic.

Best regards,

On Sun, Jun 11, 2017 at 7:21 PM, Darrell Ball <dball at vmware.com<mailto:dball at vmware.com>> wrote:

From: <ovs-discuss-bounces at openvswitch.org<mailto:ovs-discuss-bounces at openvswitch.org>> on behalf of Hui Jing <h.jingict at gmail.com<mailto:h.jingict at gmail.com>>
Date: Sunday, June 11, 2017 at 5:04 AM
To: "ovs-discuss at openvswitch.org<mailto:ovs-discuss at openvswitch.org>" <ovs-discuss at openvswitch.org<mailto:ovs-discuss at openvswitch.org>>
Subject: [ovs-discuss] vhost-user multiqueue PMD RSS

Hi all,

I am new to OVS-DPDK and trying to figure out the mechanism of vhost-user multiqueue scenario. I understand that the PMD thread is created for polling the queues of vhost-user or physical NIC and the affinity bind PMD to queues. However, the PMD transmission side confused me, I would like to learn PMD thread mechanism and how it distributes traffic to different queues.

Let's consider this scenario: one PMD thread is responsible for two queues of one vhost-user, when packet destined to the vhost-user, how it decide which queue to trasmit? is there equivalence to RSS?
                                          |Rx Queue0|
Traffic ==>PMD thread ==>                      ==>Virtio Frontend in VM
                                          |Rx Queue1|
Thanks in advance
Best Regards,

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.openvswitch.org/pipermail/ovs-discuss/attachments/20170612/88acb2e4/attachment-0001.html>

More information about the discuss mailing list