Re: Xen network domain performance for 10Gb NIC

[Jürgen Groß <jgross@xxxxxxxx>]

On 26.04.20 21:18, tosher 1 wrote:
>   Hi everyone,
>
> Lately, I have been experimenting with 10Gb NIC performance on Xen domains. I 
> have found that network performance is very poor for PV networking when a 
> driver domain is used as a network backend.
>
> My experimental setup is I have two machines connected by the 10Gb network: a 
> server running the Xen hypervisor and a desktop machine working as a client. I 
> have Ubuntu 18.04.3 LTS running on the Dom0, Domus, Driver Domain, and client 
> desktop, where the Xen version is 4.9. I measured the network bandwidth using 
> iPerf3.
>
> The network bandwidth between a DomU using Dom0 as backend and the client 
> desktop is like 9.39Gbits/sec. However, when I use a network driver domain, 
> which has the 10Gb NIC by PCI pass through, the bandwidth between the DomU and 
> the client desktop is like 2.41Gbit/sec is one direction and 4.48Gbits/sec in 
> another direction. Here, by direction, I mean the client-server direction for 
> iPerf3.
>
> These results indicate a huge performance degradation, which is unexpected. I 
> am wondering if I am missing any key points here which I should have taken care 
> of or if there is any tweak that I can apply.
Is the driver domain PV or HVM?

How many vcpus do dom0, the driver domain and the guest have?


Juergen