[ovs-dev] [RFC] QOS using queues in OVN

[Bryan Fulton]

On 5/17/16, 7:13 PM, "Ben Pfaff" <blp at ovn.org> wrote:

>On Tue, May 17, 2016 at 05:40:27PM +0530, Babu Shanmugam wrote:
>> Hi,
>> Following are my thoughts on how we can do egress shaping and dscp
>>marking
>> in OVN from what I understood from this
>> 
>><https://urldefense.proofpoint.com/v2/url?u=http-3A__openvswitch.org_pipe
>>rmail_dev_2016-2DMay_070599.html&d=CwIBAg&c=Sqcl0Ez6M0X8aeM67LKIiDJAXVeAw
>>-YihVMNtXt-uEs&r=a4TjsKvp6LvOGao2ws9fGZcs6jkTVOcFfC8bqGTV740&m=WxiRzZQcIM
>>WomWcdUt_vBAxeO8QZnwhkjf-9TMm2pzI&s=qYt0Jv6rPOmW09wMsYoDb6JWrGxov8N8Y7wLS
>>cp9-cA&e= > mail thread;
>> 
>> - Client sets the rate, burst and dscp parameters in 'options' field on
>>the
>> NB Logical_Port table.
>> - ovn-northd does the following
>>      - Figures out a free queue number and sets it in the 'options'
>>field of
>> SB Port_Binding table
>>      - Copies the rate and burst parameters from NB Logical_Port table.
>>      - Sets new actions 'set_queue(queue_number)' and
>> 'mark_dscp(dscp_value)'  in Logical_Flow that corresponds to the
>>'inport' in
>> the ls_in_port_sec_l2 stage.
>> - ovn-controller does the following
>>     - Opens the netdev that has the 'ovn-encap-ip' address. Does
>> 'ovn-encap-ip' always belong to a physical device? Is there a better
>>way in
>> finding a physical interface?
>>     - Checks and creates qdisc of type linux-htb/linux-hfsc
>>     - Checks and creates queues for all the logical ports and sets rate,
>> burst parameters
>>     - Implements the necessary openflow actions for 'set_queue' and
>> 'mark_dscp' logical actions
>
>This sounds reasonable to me.  I'm adding Bryan Fulton again in case he
>has an opinion.
>
>The best way to find the "physical" interface that a tunnel egresses is
>probably to use status:tunnel_egress_iface in the Interface table.
>(Solving this QoS problem is in fact why that status key exists, if I
>recall correctly.)

Sounds reasonable to me as well - see my previous email for using
tunnel_egress_iface to get mapping from tunnel port to PIF.
Is there a design doc for DSCP in OVN? Would love to read that over as
well. I can provide info on how we did it in NVP if there is interest.

.:bryan