[ovs-discuss] QoS HTB queue prioritization

Tue Nov 25 11:12:20 UTC 2014

Hello,

Here's how it appears after I configure the QoS and respective queues in
OVS (queue 2 should be prioritized):

root at sender:~# ovs-vsctl list qos
> _uuid               : 31d09fbf-575b-4002-806c-108c35c575f9
> external_ids        : {}
> other_config        : {}
> queues              : {1=58bf3fad-4a00-4f2a-b49c-cfbee98ae7be,
> 2=d0353556-8faf-4a18-8e4d-609f459fd119}
> type                : linux-htb
>

> root at sender:~# ovs-vsctl list queue
> _uuid               : 58bf3fad-4a00-4f2a-b49c-cfbee98ae7be
> dscp                : []
> external_ids        : {}
> other_config        : {priority="3"}
> _uuid               : d0353556-8faf-4a18-8e4d-609f459fd119
> dscp                : []
> external_ids        : {}
> other_config        : {priority="0"}

And here is how htb is configured with TC:

> root at sender:~# tc qdisc show dev eth1
> qdisc htb 1: root refcnt 2 r2q 10 default 1 direct_packets_stat 0
> direct_qlen 1000
>

> root at sender:~# tc class show dev eth1
> class htb 1:1 parent 1:fffe prio 0 rate 12Kbit ceil 10Gbit burst 1563b
> cburst 1250b
> class htb 1:fffe root rate 10Gbit ceil 10Gbit burst 1250b cburst 1250b
> class htb 1:2 parent 1:fffe prio 3 rate 12Kbit ceil 10Gbit burst 1563b
> cburst 1250b
> class htb 1:3 parent 1:fffe prio 0 rate 12Kbit ceil 10Gbit burst 1563b
> cburst 1250b

And here are 2 flow rules, one assigned to each queue:

>  cookie=0x0, duration=472.532s, table=0, n_packets=1495, n_bytes=382720,
> send_flow_rem priority=30,udp,nw_dst=10.1.2.1,tp_dst=10024
> actions=set_queue:2,output:3
>  cookie=0x0, duration=472.721s, table=0, n_packets=6358, n_bytes=9486136,
> send_flow_rem priority=30,udp,nw_dst=10.1.2.1,tp_dst=10023
> actions=set_queue:1,output:3

I am not familiar with setting up the HTB queue size with Open vSwitch. For
this situation, I guess it is configured to 1000, by the direct_qlen
parameter?

Thank you.

Best regards,
Ricardo Santos

On 25 November 2014 at 00:55, Zhangxilong <zhangxilong at h3c.com> wrote:

>  Hi, Ricado,
>
>
>
> I’m sure that HTB can work well in OVS. Could you please paste your HTB
> parameters and flow configurations? Then I might know what is the problem.
>
>
>
> And another question, how long is your queues (queue size) of HTB? Thanks.
>
>
>
> Best regards,
>
> Xilong Zhang
>
>
>
> *From:* Ricardo Santos [mailto:rrsantos at student.dei.uc.pt]
> *Sent:* 2014年11月25日 6:50
> *To:* discuss at openvswitch.org
> *Cc:* Andreas Kassler; Ognjen Dobrijević
> *Subject:* [ovs-discuss] QoS HTB queue prioritization
>
>
>
> Hello,
>
>
>
> I'm setting up a scenario in Open vSwitch where I have multiple flows that
> can be differentiated by 2 groups with different QoS configurations.
>
>
>
> Each flow from the first group has a low bandwidth requirement and should
> be prioritized over the traffic from the second group flows. Each flow from
> the second group needs a higher amount of bandwidth.
>
>
>
> So far my configuration consists in creating a HTB QoS entry in each used
> node with OVS for all the ports used to route the traffic. Then I create 2
> queues, one for each group of traffic and add flow rules with the
> appropriate enqueue options.
>
>
>
> In order to prioritize the traffic from one queue to another, I'm
> configuring the queues with the "priority" option, having the first group
> queue with priority 1 and the second with priority 2.
>
>
>
> However, I still experience packet loss in flows from the first group with
> this setup (the required bandwidth from these flows is short). Do you maybe
> know what's causing it? Shouldn't this configuration theoretically work?
>
>
>
> I was playing with the available HTB options in Open vSwitch and so far
> the only way to avoid packet loss in group 1 flows was to create a max-rate
> value in the other queue, limiting the available bandwidth, but I want to
> avoid limiting the queues' bandwidth, only prioritize the respective
> traffic.
>
>
>
> I am using Open vSwitch 2.3.0 with Ubuntu Server 14.04.1.
>
>
>
> Any help is appreciated. Thank you.
>
>
> Best regards,
>
> Ricardo Santos
>
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