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OVS Hardware Offload

The OVS software based solution is CPU intensive, affecting system performance and preventing fully utilizing available bandwidth. OVS 2.8 and above support new feature called OVS Hardware Offload which improves performance significantly. This feature allows to offload the OVS data-plane to the NIC while maintaining OVS control-plane unmodified. It is using SR-IOV technology with VF representor host net-device. The VF representor plays the same role as TAP devices in Para-Virtual (PV) setup. A packet sent through the VF representor on the host arrives to the VF, and a packet sent through the VF is received by its representor.

Supported Ethernet controllers

The following manufacturers are known to work:

  • Mellanox ConnectX-5 NIC
  • Mellanox ConnectX-6DX NIC

Prerequisites

  • Linux Kernel 5.7.0 or above
  • Open vSwitch 2.13 or above
  • iproute >= 4.12
  • sriov-device-plugin
  • multus-cni

Worker Node SR-IOV Configuration

In order to enable Open vSwitch hardware offloading, the following steps are required. Please make sure you have root privileges to run the commands below.

Check the Number of VF Supported on the NIC

cat /sys/class/net/enp3s0f0/device/sriov_totalvfs
8

Create the VFs

echo '4' > /sys/class/net/enp3s0f0/device/sriov_numvfs

Verfiy the VFs are created

ip link show enp3s0f0
8: enp3s0f0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP mode DEFAULT qlen 1000
   link/ether a0:36:9f:8f:3f:b8 brd ff:ff:ff:ff:ff:ff
   vf 0 MAC 00:00:00:00:00:00, spoof checking on, link-state auto
   vf 1 MAC 00:00:00:00:00:00, spoof checking on, link-state auto
   vf 2 MAC 00:00:00:00:00:00, spoof checking on, link-state auto
   vf 3 MAC 00:00:00:00:00:00, spoof checking on, link-state auto

Setup the PF to be up

ip link set enp3s0f0 up

Unbind the VFs from the driver

echo 0000:03:00.2 > /sys/bus/pci/drivers/mlx5_core/unbind
echo 0000:03:00.3 > /sys/bus/pci/drivers/mlx5_core/unbind
echo 0000:03:00.4 > /sys/bus/pci/drivers/mlx5_core/unbind
echo 0000:03:00.5 > /sys/bus/pci/drivers/mlx5_core/unbind

Configure SR-IOV VFs to switchdev mode

devlink dev eswitch set pci/0000:03:00.0 mode switchdev
ethtool -K enp3s0f0 hw-tc-offload on

Bind the VFs to the driver

echo 0000:03:00.2 > /sys/bus/pci/drivers/mlx5_core/bind
echo 0000:03:00.3 > /sys/bus/pci/drivers/mlx5_core/bind
echo 0000:03:00.4 > /sys/bus/pci/drivers/mlx5_core/bind
echo 0000:03:00.5 > /sys/bus/pci/drivers/mlx5_core/bind

Set hw-offload=true restart Open vSwitch

systemctl enable openvswitch.service
ovs-vsctl set Open_vSwitch . other_config:hw-offload=true
systemctl restart openvswitch.service

Worker Node SR-IOV network device plugin configuration

This plugin creates device plugin endpoints based on the configurations given in file /etc/pcidp/config.json. This configuration file is in json format as shown below:

{
    "resourceList": [
         {
            "resourceName": "cx5_sriov_switchdev",
            "selectors": {
                "vendors": ["15b3"],
                "devices": ["1018"]
            }
        }
    ]
}

Deploy SR-IOV network device plugin as daemonset see https://github.com/intel/sriov-network-device-plugin

Worker Node Multus CNI configuration

Multus Config

{
  "name": "multus-cni-network",
  "type": "multus",
  "clusterNetwork": "default",
  "defaultNetworks":[],
  "kubeconfig": "/etc/kubernetes/node-kubeconfig.yaml"
}

Deploy multus CNI as daemonset see https://github.com/intel/multus-cni

Create NetworkAttachementDefinition CRD with OVN CNI config

Kubernetes Network CRD Spec:
apiVersion: "k8s.cni.cncf.io/v1"
kind: NetworkAttachmentDefinition
metadata:
  name: default
  annotations:
    k8s.v1.cni.cncf.io/resourceName: mellanox.com/cx5_sriov_switchdev
spec:
  Config: '{"cniVersion":"0.3.1","name":"ovn-kubernetes","type":"ovn-k8s-cni-overlay","ipam":{},"dns":{}}'

Deploy POD with OVS hardware-offload

Create POD spec and

apiVersion: v1
kind: Pod
metadata:
  name: ovs-offload-pod1
  annotations:
    v1.multus-cni.io/default-network: default
spec:
  containers:
  - name: appcntr1
    image: centos/tools
    resources:
      requests:
        mellanox.com/cx5_sriov_switchdev: '1'
      limits:
        mellanox.com/cx5_sriov_switchdev: '1'

Verify Hardware-Offload is working

Lookup VF representor, in this example it is e5a1c8fcef0f327

$ ip link show enp3s0f0
6: enp3s0f0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq master ovs-system state UP mode DEFAULT group default qlen 1000
   link/ether ec:0d:9a:46:9e:84 brd ff:ff:ff:ff:ff:ff
   vf 0 MAC 00:00:00:00:00:00, spoof checking off, link-state enable, trust off, query_rss off
   vf 1 MAC 00:00:00:00:00:00, spoof checking off, link-state enable, trust off, query_rss off
   vf 2 MAC 00:00:00:00:00:00, spoof checking off, link-state enable, trust off, query_rss off
   vf 3 MAC fa:16:3e:b9:b8:ce, vlan 57, spoof checking on, link-state enable, trust off, query_rss off

compute_node2# ls -l /sys/class/net/
lrwxrwxrwx 1 root root 0 Sep 11 10:54 eth0 -> ../../devices/virtual/net/eth0
lrwxrwxrwx 1 root root 0 Sep 11 10:54 eth1 -> ../../devices/virtual/net/eth1
lrwxrwxrwx 1 root root 0 Sep 11 10:54 eth2 -> ../../devices/virtual/net/eth2
lrwxrwxrwx 1 root root 0 Sep 11 10:54 e5a1c8fcef0f327 -> ../../devices/virtual/net/e5a1c8fcef0f327

Access the POD

kubectl exec -it ovs-offload-pod1 -- /bin/bash

Ping other POD on second worker node

ping ovs-offload-pod2

Check traffic on the VF representor port. Verify that only the first ICMP packet appears

tcpdump -nnn -i e5a1c8fcef0f327

tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
17:12:41.260487 IP 172.0.0.13 > 172.0.0.10: ICMP echo request, id 1263, seq 1, length 64
17:12:41.260778 IP 172.0.0.10 > 172.0.0.13: ICMP echo reply, id 1263, seq 1, length 64
17:12:46.268951 ARP, Request who-has 172.0.0.13 tell 172.0.0.10, length 42
17:12:46.271771 ARP, Reply 172.0.0.13 is-at fa:16:3e:1a:10:05, length 46
17:12:55.354737 IP6 fe80::f816:3eff:fe29:8118 > ff02::1: ICMP6, router advertisement, length 64
17:12:56.106705 IP 0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request from 62:21:f0:89:40:73, length 30

OVS hardware offload DPU support

Data Processing Units (DPU) combine the advanced capabilities of a Smart-NIC (such as Mellanox ConnectX-6DX NIC) with a general purpose embedded CPU and a high-speed memory controller.

Similarly to Smart-NICs, a DPU follows the kernel switchdev model. In this model, every VF/PF net-device on the host has a corresponding representor net-device existing on the embedded CPU.

Supported DPUs

The following manufacturers are known to work:

Deployment guide can be found here.

vDPA

vDPA (Virtio DataPath Acceleration) is a technology that enables the acceleration of virtIO devices while allowing the implementations of such devices (e.g: NIC vendors) to use their own control plane.

vDPA can be combined with the SR-IOV OVS Hardware offloading setup to expose the workload to an open standard interface such as virtio-net.

Additional Prerequisites:

  • Linux Kernel >= 5.12
  • iproute >= 5.14

Supported Hardware:

  • Mellanox ConnectX-6DX NIC

Additional configuration

In addition to all the steps listed above, insert the virtio-vdpa driver and the mlx-vdpa driver:

$ modprobe vdpa
$ modprobe virtio-vdpa
$ modprobe mlx5-vdpa

The the vdpa tool (part of iproute package) is used to create a vdpa device on top of an existing VF:

$ vdpa mgmtdev show
pci/0000:65:00.2:
  supported_classes net
$ vdpa dev add name vdpa2 mgmtdev pci/0000:65:00.2
$ vdpa dev list
vdpa2: type network mgmtdev pci/0000:65:00.2 vendor_id 5555 max_vqs 16 max_vq_size 256

After a device has been created, the SR-IOV Device Plugin plugin configuration has to be modified for it to select and expose the vdpa device:

{
    "resourceList": [
         {
            "resourceName": "cx6_sriov_vpda_virtio",
            "selectors": {
               "vendors": ["15b3"],
               "devices": ["101e"],
               "vdpaType": "virtio"
            }
        }
    ]
}