Re: [RFC net-next] net: veth: reduce page_pool memory footprint using half page per-buffer

Jakub Kicinski
2023-05-17T14:58:51Z

On Wed, 17 May 2023 00:52:25 +0200 Lorenzo Bianconi wrote:
> I am testing this RFC patch in the scenario reported below:
>
> iperf tcp tx --> veth0 --> veth1 (xdp_pass) --> iperf tcp rx
>
> - 6.4.0-rc1 net-next:
> MTU 1500B: ~ 7.07 Gbps
> MTU 8000B: ~ 14.7 Gbps
>
> - 6.4.0-rc1 net-next + page_pool frag support in veth:
> MTU 1500B: ~ 8.57 Gbps
> MTU 8000B: ~ 14.5 Gbps
>
> side note: it seems there is a regression between 6.2.15 and 6.4.0-rc1 net-next
> (even without latest veth page_pool patches) in the throughput I can get in the
> scenario above, but I have not looked into it yet.
>
> - 6.2.15:
> MTU 1500B: ~ 7.91 Gbps
> MTU 8000B: ~ 14.1 Gbps
>
> - 6.4.0-rc1 net-next w/o commits [0],[1],[2]
> MTU 1500B: ~ 6.38 Gbps
> MTU 8000B: ~ 13.2 Gbps

If the benchmark is iperf, wouldn't working towards preserving GSO
status across XDP (assuming prog is multi-buf-capable) be the most
beneficial optimization?