Re: [PATCHv4 bpf-next 0/2] xdp: add dev map multicast support

Hangbin Liu
2020-06-04T04:09:54Z

On Wed, Jun 03, 2020 at 01:05:28PM +0200, Toke Høiland-Jørgensen wrote:
> > Hi Toke,
> >
> > Here is the result I tested with 2 i40e 10G ports on physical machine.
> > The pktgen pkt_size is 64.
>
> These numbers seem a bit low (I'm getting ~8.5MPPS on my test machine
> for a simple redirect). Some of that may just be performance of the
> machine, I guess (what are you running this on?), but please check that
> you are not limited by pktgen itself - i.e., that pktgen is generating
> traffic at a higher rate than what XDP is processing.

Here is the test topology, which looks like

Host A | Host B | Host C
eth0 + eth0 - eth1 + eth0

I did pktgen sending on Host A, forwarding on Host B.
Host B is a Dell PowerEdge R730 (128G memory, Intel(R) Xeon(R) CPU E5-2690 v3)
eth0, eth1 is an onboard i40e 10G driver

Test 1: add eth0, eth1 to br0 and test bridge forwarding
Test 2: Test xdp_redirect_map(), eth0 is ingress, eth1 is egress
Test 3: Test xdp_redirect_map_multi(), eth0 is ingress, eth1 is egress

>
> > Bridge forwarding(I use sample/bpf/xdp1 to count the PPS, so there are two modes data):
> > generic mode: 1.32M PPS
> > driver mode: 1.66M PPS
>
> I'm not sure I understand this - what are you measuring here exactly?

> Finally, since the overhead seems to be quite substantial: A comparison
> with a regular network stack bridge might make sense? After all we also
> want to make sure it's a performance win over that :)

I though you want me also test with bridge forwarding. Am I missing something?

>
> > xdp_redirect_map:
> > generic mode: 1.88M PPS
> > driver mode: 2.74M PPS
>
> Please add numbers without your patch applied as well, for comparison.

OK, I will.
>
> > xdp_redirect_map_multi:
> > generic mode: 1.38M PPS
> > driver mode: 2.73M PPS
>
> I assume this is with a single interface only, right? Could you please
> add a test with a second interface (so the packet is cloned) as well?
> You can just use a veth as the second target device.

OK, so the topology on Host B should be like

eth0 + eth1 + veth0, eth0 as ingress, eth1 and veth0 as egress, right?

Thanks
Hangbin