WorkContemplation

VFd

manages configuration of VF and PF (att/vfd https://github.com/att/vfd/wiki, testpmd http://dpdk.org/doc/guides/howto/vfd.html)
used with DPDK PF with DPDK VF (VFd features fails with kernel PF)
services such as filtering, QoS, DPI can be offloaded on the host fast path

Neutron Equivalent functionality supported by VFd

VLAN_FILTER | OVS Firewall – filters traffic based on a list of VLAN ID(s), this filter is applied on SR-IOV VF before passing the traffic to VM.
VLAN_STRIP | vlan transparency – Enable to strip outer VLAN tag per VF
INSERT_STAG | OVS does this already. – Enable to Insert outer VLAN tag per VF
BROADCAST_ALLOW | traffic protection – Enable to allow broadcast per VF
UNKNOWN_UNICAST_ALLOW | traffic protection – Enable to allow unicast per VF
UNKNOWN_MULTICAST_ALLOW | traffic protection – Enable to allow multicast per VF
MAC_FILTER | allowed address pairs – Directs outbound traffic based on a list of MAC address. This will allow a VM to transmit packets with specified source MAC address in addition to MAC which belongs to VM
VLAN_ANTI_SPOOF_CHECK | port security – enable to ensure anti MAC spoof checks are done at the SR-IOV VF level to comply with security.

In development

Network QoS: bandwidth allocation, prioritization, and rate limiting
Packet mirroring from one VF to another
Improved analytics interface to report basic packet level statistics on PF and VF

Cons

high CPU overhead
Does not work with kernel PF

SR-IOV HW offload

-offload the OVS processing to a SmartNIC
-implement the OVS datapath directly on the adapter
-frees up additional cores to run more applications
-North/South performance scales with the number of VNF VM

Cons

East/West SR-IOV performance does not seem to scale,due to increase in PCIe load

OVS hardware offload integration with openstack:

Representor:

representor port profile. https://review.openstack.org/#/c/483921/
Plug and unplug representor from OVS https://review.openstack.org/#/c/398277/

Scheduling
At present openstack does not differentiate between SRIOV hardware and OVS offload , so it would not be possible to use both on same host.nic feature based scheduling(enable-sriov-nic-features) might be used in future to solve the above issue, by scheduling using “capabilities” openstack port create –binding-profile ‘{“capabilities”: [“hw-tc-offload”]}’

https://specs.openstack.org/openstack/nova-specs/specs/pike/approved/enable-sriov-nic-features.html

OVS:
Regular OVS datapath is used for hw-offload.
.https://review.openstack.org/#/c/483459/

Nova support for OVS offload
Enable VIF_TYPE_OVS with vnic_type direct
https://review.openstack.org/#/c/398265/