On 5/24/20 12:13 PM, Christian Deacon wrote: > Hey David, > > > Thank you for your response! > > > The VM only has one CPU right now. It's possible the cluster has 8 RX > queues I'd imagine, but I don't have that information sadly. I executed > the same command on another VM I have with two CPUs (not being used for > the XDP-native testing): > > > ``` > > root@Test:~# ethtool -l ens3 > Channel parameters for ens3: > Pre-set maximums: > RX: 0 > TX: 0 > Other: 0 > Combined: 8 > Current hardware settings: > RX: 0 > TX: 0 > Other: 0 > Combined: 2 > ``` That's odd that they give you 8 queues for a 1 cpu VM. This is vultr? I may have to spin up a VM there and check it out. > > > I did receive this from my hosting provider when asking which NIC driver > they use: ... > > I agree with the provider - the hardware nic's are not relevant to the VM. > To my understanding, if the NIC isn't offloading packets directly to our > VPS, wouldn't this destroy the purpose of using XDP-native over > XDP-generic/SKB mode for performance in our case? I was under the > assumption that was the point of XDP-native. If so, I'm not sure why the > program is loading with XDP-native without any issues besides the AF_XDP > program. The host is essentially the network to your VM / VPS. What data structure it uses is not relevant to what you want to do inside the VM. Right now there are a lot of missing features for the host OS to rely solely on XDP frames. Inside the VM kernel, efficiency of XDP depends on what you are trying to do. A 1 or 2-cpu VM with 8 queues meets the resource requirement for XDP programs; I am not familiar with the details on AF_XDP to know if some kind of support is missing inside the virtio driver. > > > I will admit I've been wondering what the difference is between > `XDP_FLAGS_DRV_MODE` (XDP-native) and `XDP_FLAGS_HW_MODE` since I > thought XDP-native was offloading packets from the NIC. H/W mode means the program is pushed down to the hardware. I believe only netronome's nic currently does offload. Some folks have discussed offloading programs for the virtio NIC, but that does not work today.
|