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Hi Satish,

Why dont you use DPDK?

Thanks

On Thu, 7 Sep 2023 at 19:03 Satish Patel <satish.txt at gmail.com> wrote:

> I totally agreed with Sean on all his points but trust me, I have tried
> everything possible to tune OS, Network stack, multi-queue, NUMA, CPU
> pinning and name it.. but I didn't get any significant improvement. You may
> gain 2 to 5% gain with all those tweek. I am running the entire workload on
> sriov and life is happy except no LACP bonding.
>
> I am very interesting is this project
> https://docs.openvswitch.org/en/latest/intro/install/afxdp/
>
> On Thu, Sep 7, 2023 at 6:07 AM Ha Noi <hanoi952022 at gmail.com> wrote:
>
>> Dear Smoney,
>>
>>
>>
>> On Thu, Sep 7, 2023 at 12:41 AM <smooney at redhat.com> wrote:
>>
>>> On Wed, 2023-09-06 at 11:43 -0400, Satish Patel wrote:
>>> > Damn! We have noticed the same issue around 40k to 55k PPS. Trust me
>>> > nothing is wrong in your config. This is just a limitation of the
>>> software
>>> > stack and kernel itself.
>>> its partly determined by your cpu frequency.
>>> kernel ovs of yesteryear could handel about 1mpps total on a ~4GHZ
>>> cpu. with per port troughpuyt being lower dependin on what qos/firewall
>>> rules that were apllied.
>>>
>>>
>>
>> My CPU frequency is 3Ghz and using CPU Intel Gold 2nd generation. I think
>> the problem is tuning in the compute node inside. But I cannot find any
>> guide or best practices for it.
>>
>>
>>
>>> moving form iptables firewall to ovs firewall can help to some degree
>>> but your partly trading connection setup time for statead state troughput
>>> with the overhead of the connection tracker in ovs.
>>>
>>> using stateless security groups can help
>>>
>>> we also recently fixed a regression cause by changes in newer versions
>>> of ovs.
>>> this was notable in goign form rhel 8 to rhel 9 where litrally it reduced
>>> small packet performce to 1/10th and jumboframes to about 1/2
>>> on master we have a config option that will set the default qos on a
>>> port to linux-noop
>>>
>>> https://github.com/openstack/os-vif/blob/master/vif_plug_ovs/ovs.py#L106-L125
>>>
>>> the backports are propsoed upstream
>>> https://review.opendev.org/q/Id9ef7074634a0f23d67a4401fa8fca363b51bb43
>>> and we have backported this downstream to adress that performance
>>> regression.
>>> the upstram backport is semi stalled just ebcasue we wanted to disucss
>>> if we shoudl make ti opt in
>>> by default upstream while backporting but it might be helpful for you if
>>> this is related to yoru current
>>> issues.
>>>
>>> 40-55 kpps is kind of low for kernel ovs but if you have a low clockrate
>>> cpu, hybrid_plug + incorrect qos
>>> then i could see you hitting such a bottelneck.
>>>
>>> one workaround by the way without the os-vif workaround backported is to
>>> set
>>> /proc/sys/net/core/default_qdisc to not apply any qos or a low overhead
>>> qos type
>>> i.e. sudo sysctl -w net.core.default_qdisc=pfifo_fast
>>>
>>>
>>
>>> that may or may not help but i would ensure that your are not usign
>>> somting like fqdel or cake
>>> for net.core.default_qdisc and if you are try changing it to pfifo_fast
>>> and see if that helps.
>>>
>>> there isnet much you can do about the cpu clock rate but ^ is somethign
>>> you can try for free
>>> note it wont actully take effect on an exsitng vm if you jsut change the
>>> default but you can use
>>> tc to also chagne the qdisk for testing. hard rebooting the vm shoudl
>>> also make the default take effect.
>>>
>>> the only other advice i can give assuming kernel ovs is the only option
>>> you have is
>>>
>>> to look at
>>>
>>> https://docs.openstack.org/nova/latest/configuration/config.html#libvirt.rx_queue_size
>>>
>>> https://docs.openstack.org/nova/latest/configuration/config.html#libvirt.tx_queue_size
>>> and
>>>
>>> https://docs.openstack.org/nova/latest/configuration/extra-specs.html#hw:vif_multiqueue_enabled
>>>
>>> if the bottelneck is actully in qemu or the guest kernel rather then ovs
>>> adjusting the rx/tx queue size and
>>> using multi queue can help. it will have no effect if ovs is the bottel
>>> neck.
>>>
>>>
>>>
>> I have set this option to 1024, and enable multiqueue as well. But it did
>> not help.
>>
>>
>>> >
>>> > On Wed, Sep 6, 2023 at 9:21 AM Ha Noi <hanoi952022 at gmail.com> wrote:
>>> >
>>> > > Hi Satish,
>>> > >
>>> > > Actually, our customer get this issue when the tx/rx above only 40k
>>> pps.
>>> > > So what is the threshold of this throughput for OvS?
>>> > >
>>> > >
>>> > > Thanks and regards
>>> > >
>>> > > On Wed, 6 Sep 2023 at 20:19 Satish Patel <satish.txt at gmail.com>
>>> wrote:
>>> > >
>>> > > > Hi,
>>> > > >
>>> > > > This is normal because OVS or LinuxBridge wire up VMs using TAP
>>> interface
>>> > > > which runs on kernel space and that drives higher interrupt and
>>> that makes
>>> > > > the kernel so busy working on handling packets. Standard
>>> OVS/LinuxBridge
>>> > > > are not meant for higher PPS.
>>> > > >
>>> > > > If you want to handle higher PPS then look for DPDK or SRIOV
>>> deployment.
>>> > > > ( We are running everything in SRIOV because of high PPS
>>> requirement)
>>> > > >
>>> > > > On Tue, Sep 5, 2023 at 11:11 AM Ha Noi <hanoi952022 at gmail.com>
>>> wrote:
>>> > > >
>>> > > > > Hi everyone,
>>> > > > >
>>> > > > > I'm using Openstack Train and Openvswitch for ML2 driver and GRE
>>> for
>>> > > > > tunnel type. I tested our network performance between two VMs
>>> and suffer
>>> > > > > packet loss as below.
>>> > > > >
>>> > > > > VM1: IP: 10.20.1.206
>>> > > > >
>>> > > > > VM2: IP: 10.20.1.154 <https://10.20.1.154/24>
>>> > > > >
>>> > > > > VM3: IP: 10.20.1.72
>>> > > > >
>>> > > > >
>>> > > > > Using iperf3 to testing performance between VM1 and VM2.
>>> > > > >
>>> > > > > Run iperf3 client and server on both VMs.
>>> > > > >
>>> > > > > On VM2: iperf3 -t 10000 -b 130M -l 442 -P 6 -u -c 10.20.1.206
>>> > > > >
>>> > > > > On VM1: iperf3 -t 10000 -b 130M -l 442 -P 6 -u -c 10.20.1.154
>>> > > > > <https://10.20.1.154/24>
>>> > > > >
>>> > > > >
>>> > > > > Using VM3 ping into VM1, then the packet is lost and the latency
>>> is
>>> > > > > quite high.
>>> > > > >
>>> > > > >
>>> > > > > ping -i 0.1 10.20.1.206
>>> > > > >
>>> > > > > PING 10.20.1.206 (10.20.1.206) 56(84) bytes of data.
>>> > > > >
>>> > > > > 64 bytes from 10.20.1.206: icmp_seq=1 ttl=64 time=7.70 ms
>>> > > > >
>>> > > > > 64 bytes from 10.20.1.206: icmp_seq=2 ttl=64 time=6.90 ms
>>> > > > >
>>> > > > > 64 bytes from 10.20.1.206: icmp_seq=3 ttl=64 time=7.71 ms
>>> > > > >
>>> > > > > 64 bytes from 10.20.1.206: icmp_seq=4 ttl=64 time=7.98 ms
>>> > > > >
>>> > > > > 64 bytes from 10.20.1.206: icmp_seq=6 ttl=64 time=8.58 ms
>>> > > > >
>>> > > > > 64 bytes from 10.20.1.206: icmp_seq=7 ttl=64 time=8.34 ms
>>> > > > >
>>> > > > > 64 bytes from 10.20.1.206: icmp_seq=8 ttl=64 time=8.09 ms
>>> > > > >
>>> > > > > 64 bytes from 10.20.1.206: icmp_seq=10 ttl=64 time=4.57 ms
>>> > > > >
>>> > > > > 64 bytes from 10.20.1.206: icmp_seq=11 ttl=64 time=8.74 ms
>>> > > > >
>>> > > > > 64 bytes from 10.20.1.206: icmp_seq=12 ttl=64 time=9.37 ms
>>> > > > >
>>> > > > > 64 bytes from 10.20.1.206: icmp_seq=14 ttl=64 time=9.59 ms
>>> > > > >
>>> > > > > 64 bytes from 10.20.1.206: icmp_seq=15 ttl=64 time=7.97 ms
>>> > > > >
>>> > > > > 64 bytes from 10.20.1.206: icmp_seq=16 ttl=64 time=8.72 ms
>>> > > > >
>>> > > > > 64 bytes from 10.20.1.206: icmp_seq=17 ttl=64 time=9.23 ms
>>> > > > >
>>> > > > > ^C
>>> > > > >
>>> > > > > --- 10.20.1.206 ping statistics ---
>>> > > > >
>>> > > > > 34 packets transmitted, 28 received, 17.6471% packet loss, time
>>> 3328ms
>>> > > > >
>>> > > > > rtt min/avg/max/mdev = 1.396/6.266/9.590/2.805 ms
>>> > > > >
>>> > > > >
>>> > > > >
>>> > > > > Does any one get this issue ?
>>> > > > >
>>> > > > > Please help me. Thanks
>>> > > > >
>>> > > >
>>>
>>>
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