[libvirt] [RFC] Add support for NIC offload discovery

[Michal Privoznik]

On 22.10.2014 14:02, Chapman, James P wrote:
> Currently libvirt provides lots of useful information on the HW
> capabilities of the host and its attached devices. I’m interested in
> extending the HW capability discovery of libvirt, to a point where it is
> capable of discovering the HW offload capabilities of host PCI devices.
> Take a NIC for example, this feature would enable libvirt discover the
> supported NIC offload features, csum, tso, etc.
>
> So where might a feature like this be used. Consider an Openstack
> deployment, a VM may have a workload that depends on specific NIC HW
> offload capabilities in order to stay within certain throughput, CPU
> utilisation or latency thresholds. For this scenario, it’s important
> that the VM is placed on a host with PCI devices that provide the
> required NIC HW offload capabilities. If libvirt could provide this
> functionality, this information could be used during the VM scheduling
> phase when all nodes are evaluated for their suitability.
>
>  From what I understand, libvirt currently uses ioctl’s to get the NIC
> state, MTU, etc. Could the ethtool ioctl framework be used to discover
> the HW offload features provided by the hosts network controllers.
>

Right. While libvirt already allows setting these knobs on a NIC (thanks 
to Jan and his commit 5b3536ae) it is not exposing this info. I'd say 
open a bug or propose the patches. I think it's worth-having functionality.

Michal