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

Hangbin Liu [off-list ref] writes:

On Thu, Jun 04, 2020 at 06:02:54PM +0200, Toke Høiland-Jørgensen wrote:

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Hangbin Liu [off-list ref] writes:

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On Thu, Jun 04, 2020 at 02:37:23PM +0200, Toke Høiland-Jørgensen wrote:

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Now I use the ethtool_stats.pl to count forwarding speed and here is the result:

With kernel 5.7(ingress i40e, egress i40e)
XDP:
bridge: 1.8M PPS
xdp_redirect_map:
  generic mode: 1.9M PPS
  driver mode: 10.4M PPS

Ah, now we're getting somewhere! :)

quoted

Kernel 5.7 + my patch(ingress i40e, egress i40e)
bridge: 1.8M
xdp_redirect_map:
  generic mode: 1.86M PPS
  driver mode: 10.17M PPS

Right, so this corresponds to a ~2ns overhead (10**9/10400000 -
10**9/10170000). This is not too far from being in the noise, I suppose;
is the difference consistent?

Sorry, I didn't get, what different consistent do you mean?

I meant, how much do the numbers vary between each test run?

Oh, when run it at the same period, the number is stable, the range is about
~0.05M PPS. But after a long time or reboot, the speed may changed a little.
Here is the new test result after I reboot the system:

Kernel 5.7 + my patch(ingress i40e, egress i40e)
xdp_redirect_map:
  generic mode: 1.9M PPS
  driver mode: 10.2M PPS

xdp_redirect_map_multi:
  generic mode: 1.58M PPS
  driver mode: 7.16M PPS

Kernel 5.7 + my patch(ingress i40e, egress i40e + veth(No XDP on peer))
xdp_redirect_map:
  generic mode: 2.2M PPS
  driver mode: 14.2M PPS

This looks wrong - why is performance increasing when adding another
target? How are you even adding another target to regular
xdp_redirect_map?

-Toke