XDP challenges and metadata usage : Jesper want to put HW offloads into metadata, remove the need to disable HW offload to use XDP, intoducing HW features will be easier, no need to get patches into the kernel.
Arnd: guest eBPF and XDP, is there a way to move the filter one level up, this has been approached before, so far failed, security is an issue becasue bpf can access memory.
Bill do you have any material, how does this out perform OVS for example. Ilias has a link David ? XDP vs OVS
OVS always allocates an SKB
H/W offloading features
virtio work items
virtio_net and XDP TX-queue problem
Packets get dropped if mis configured TX buffers, more of an issue with 100s queu per machine - think virtual cpus
virtio_net and XDP-multi-buffer support
can now support jumbo frames, also TSO can try to redirect big packet, results in performance drop when you expected boost. Alex does this resduce switchign overhead, yes it can pull as much as it has secduled time to do so.
Arndvirtio_net and scheduling the VM to consume packets (current bottleneck for PPS performance)
From host be smarter in schduling with guest
Alex : been looking at performance - virtio-audio/video - similar probelms of moving data between guests - vm exits
virtio-net - you mean the driver seen by the guest ? the guest sees the same thing, the back ends can change Arnd : two areas, in guest to rerout in the same guest this is easy case. Host is KVM we have to vhost-next devices and this is more interesting.