[ovs-discuss] [OVN] QoS rules share the same Openflow meter

Dumitru Ceara dceara at redhat.com
Wed Mar 25 14:04:26 UTC 2020


On 3/24/20 2:33 PM, Maciej Jozefczyk wrote:
> Hi all!
> 
> I have the following setup:
> - Logical Switch with 3 Logical Ports that are VMs:
>    * 1 LSP from which i test QoS with iperf3
>    * 2 LSPs have QoS policy set.
> 
> Configured QoS rules:
> --------------------------------------------------------------------------------------------------------
> stack at mjozefcz-devstack-qos:~$ ovn-nbctl list qos
> _uuid               : 7ad43edb-ed2a-4279-8373-f925a6591508
> action              : {}
> bandwidth           : {burst=10000, rate=10000}
> direction           : from-lport
> external_ids        : {}
> match               : "inport == \"0dbccc4f-5c36-406e-a629-70d49d52e391\""
> priority            : 2002
> 
> _uuid               : 8ecac46b-1ec0-4e76-a9e0-0b3063fc79e0
> action              : {}
> bandwidth           : {burst=10000, rate=10000}
> direction           : from-lport
> external_ids        : {}
> match               : "inport == \"cad88274-feea-4ddb-b8c1-af49ca8833cf\""
> priority            : 2002
> stack at mjozefcz-devstack-qos:~$ 
> --------------------------------------------------------------------------------------------------------
> Please note that the rules have the same bandwidth configuration.
> Those QoS rules are mapped for those two logical flows:
> 
> -----------------------------------------------------------------------------------------------------------------------------------------------
> stack at mjozefcz-devstack-qos:~$ ovn-sbctl list logical_flow
> 7ae15276-6869-40ac-be1d-b4707dcf5dc7
> _uuid               : 7ae15276-6869-40ac-be1d-b4707dcf5dc7
> actions             : "set_meter(10000, 10000); next;"
> external_ids        : {source="ovn-northd.c:5451",
> stage-hint="8ecac46b", stage-name=ls_in_qos_meter}
> logical_datapath    : 9a1af1f9-7b42-43c2-ab0b-f4796d209e63
> match               : "inport == \"cad88274-feea-4ddb-b8c1-af49ca8833cf\""
> pipeline            : ingress
> priority            : 2002
> table_id            : 8
> hash                : 0
> stack at mjozefcz-devstack-qos:~$ ovn-sbctl list logical_flow
> f541520a-ef70-4038-8ee5-b5b609fc3883
> _uuid               : f541520a-ef70-4038-8ee5-b5b609fc3883
> actions             : "set_meter(10000, 10000); next;"
> external_ids        : {source="ovn-northd.c:5451",
> stage-hint="7ad43edb", stage-name=ls_in_qos_meter}
> logical_datapath    : 9a1af1f9-7b42-43c2-ab0b-f4796d209e63
> match               : "inport == \"0dbccc4f-5c36-406e-a629-70d49d52e391\""
> pipeline            : ingress
> priority            : 2002
> table_id            : 8
> hash                : 0
> stack at mjozefcz-devstack-qos:~$ 
> -----------------------------------------------------------------------------------------------------------------------------------------------
> 
> The problem is that those two rules use the same meter (meter id 2):
> -----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
> stack at mjozefcz-devstack-qos:~$ sudo ovs-ofctl -O OpenFlow13 dump-flows
> br-int | grep meter
>  cookie=0xf541520a, duration=4215.163s, table=16, n_packets=12497,
> n_bytes=15463221, priority=2002,reg14=0x4,metadata=0x1
> actions=meter:2,resubmit(,17)
>  cookie=0x7ae15276, duration=4215.163s, table=16, n_packets=13789,
> n_bytes=33132305, priority=2002,reg14=0x5,metadata=0x1
> actions=meter:2,resubmit(,17)
> stack at mjozefcz-devstack-qos:~$ sudo ovs-ofctl -O OpenFlow13 dump-meters
> br-int
> OFPST_METER_CONFIG reply (OF1.3) (xid=0x2):
> meter=2 kbps burst stats bands=
> type=drop rate=10000 burst_size=10000
> stack at mjozefcz-devstack-qos:~$ sudo ovs-ofctl -O OpenFlow13 meter-stats
> br-int
> OFPST_METER reply (OF1.3) (xid=0x2):
> meter:2 flow_count:2 packet_in_count:21607 byte_in_count:40746921
> duration:4158.558s bands:
> 0: packet_count:2010 byte_count:6486212
> -----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
> 
> So if there are more than one Logical Switch Ports from the same Logical
> Switch bound on the chassis that share the same QoS BW limit settings,
> those also share the same meter.
> That ends with slitted bw limit across those Logical Switch Ports.
> I tested it using iperf3, the results:
> 
> If only one LSP consumes the limit:
> -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
> stack at mjozefcz-devstack-qos:~$ sudo ip netns exec
> ovnmeta-9a1af1f9-7b42-43c2-ab0b-f4796d209e63 iperf3 -R -O 1 -c 10.1.0.20
> Connecting to host 10.1.0.20, port 5201
> Reverse mode, remote host 10.1.0.20 is sending
> [  4] local 10.1.0.2 port 57206 connected to 10.1.0.20 port 5201
> [ ID] Interval           Transfer     Bandwidth
> [  4]   0.00-1.00   sec  3.49 MBytes  29.3 Mbits/sec                
>  (omitted)
> [  4]   0.00-1.00   sec  1.06 MBytes  8.86 Mbits/sec                  
> [  4]   1.00-2.00   sec  1.37 MBytes  11.5 Mbits/sec                  
> [  4]   2.00-3.00   sec  1.16 MBytes  9.71 Mbits/sec                  
> [  4]   3.00-4.00   sec  1.17 MBytes  9.80 Mbits/sec                  
> [  4]   4.00-5.00   sec  1.17 MBytes  9.84 Mbits/sec                  
> [  4]   5.00-6.00   sec  1.13 MBytes  9.46 Mbits/sec                  
> [  4]   6.00-7.00   sec  1.04 MBytes  8.76 Mbits/sec                  
> [  4]   7.00-8.00   sec  1.26 MBytes  10.6 Mbits/sec                  
> [  4]   8.00-9.00   sec  1.06 MBytes  8.88 Mbits/sec                  
> [  4]   9.00-10.00  sec  1.33 MBytes  11.2 Mbits/sec                  
> - - - - - - - - - - - - - - - - - - - - - - - - -
> [ ID] Interval           Transfer     Bandwidth       Retr
> [  4]   0.00-10.00  sec  11.7 MBytes  9.78 Mbits/sec  2554            
> sender
> [  4]   0.00-10.00  sec  11.7 MBytes  9.85 Mbits/sec                
>  receiver
> 
> iperf Done.
> stack at mjozefcz-devstack-qos:~$ 
> -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
> 
> If two VMs are using the meter - two iperf3 tests at the same time:
> stack at mjozefcz-devstack-qos:~$ sleep 1; sudo ip netns exec
> ovnmeta-9a1af1f9-7b42-43c2-ab0b-f4796d209e63 iperf3 -R -c 1
> 0.1.0.16
> Connecting to host 10.1.0.16, port 5201
> Reverse mode, remote host 10.1.0.16 is sending
> [  4] local 10.1.0.2 port 56874 connected to 10.1.0.16 port 5201
> [ ID] Interval           Transfer     Bandwidth
> [  4]   0.00-1.00   sec  3.39 MBytes  28.5 Mbits/sec                  
> [  4]   1.00-2.00   sec  69.6 KBytes   570 Kbits/sec                  
> [  4]   2.00-3.00   sec   456 KBytes  3.74 Mbits/sec                  
> [  4]   3.00-4.00   sec   290 KBytes  2.38 Mbits/sec                  
> [  4]   4.00-5.00   sec   534 KBytes  4.37 Mbits/sec                  
> [  4]   5.00-6.00   sec   324 KBytes  2.65 Mbits/sec                  
> [  4]   6.00-7.00   sec  16.8 KBytes   137 Kbits/sec                  
> [  4]   7.00-8.00   sec   474 KBytes  3.89 Mbits/sec                  
> [  4]   8.00-9.00   sec   400 KBytes  3.27 Mbits/sec                  
> [  4]   9.00-10.00  sec   750 KBytes  6.15 Mbits/sec                  
> - - - - - - - - - - - - - - - - - - - - - - - - -
> [ ID] Interval           Transfer     Bandwidth       Retr
> [  4]   0.00-10.00  sec  6.92 MBytes  5.80 Mbits/sec  867             sender
> [  4]   0.00-10.00  sec  6.63 MBytes  5.56 Mbits/sec                
>  receiver
> 
> iperf Done.
> -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
> 
> Questions:
> - Can we create separate meter for each QoS row, to not share the same
> meter if the rules are the same (except match)?

Hi Maciej,

>From what I see the problem is that we assign meter IDs based only on
the rate and burst specified in the "set_meter()" action [1].

I guess we should probably change the set_meter() action such that
ovn-northd specifies another field (maybe port or "match" or some other
unique id?) to be used when building the meter name. This should create
unique meters.

I amm however not too familiar with the implementation details of the
QoS functionality so maybe there are other options.

Regards,
Dumitru

[1] https://github.com/ovn-org/ovn/blob/v20.03.0/lib/actions.c#L2786

> - If we would introduce QoS for Port Groups [1], can we also use
> separate meters?
> 
> Versions used:
> - OVN 20.03
> - OVS
> 
> Thanks,
> Maciej
> 
> [1] https://mail.openvswitch.org/pipermail/ovs-discuss/2020-March/049864.html
> 
> -- 
> Best regards,
> Maciej Józefczyk
> 
> _______________________________________________



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