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Because DPDK required DPDK support inside guest VM. It's not suitable for
general purpose workload. You need your guest VM network to support DPDK to
get 100% throughput.

On Thu, Sep 7, 2023 at 8:06 AM Ha Noi <hanoi952022 at gmail.com> wrote:

> 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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