RE: [PATCH v7 bpf-next 0/6] xsk: build skb by page (aka generic zerocopy xmit)

[John Fastabend <john.fastabend@gmail.com>]

Alexander Lobakin wrote:
> This series introduces XSK generic zerocopy xmit by adding XSK umem
> pages as skb frags instead of copying data to linear space.
> The only requirement for this for drivers is to be able to xmit skbs
> with skb_headlen(skb) == 0, i.e. all data including hard headers
> starts from frag 0.
> To indicate whether a particular driver supports this, a new netdev
> priv flag, IFF_TX_SKB_NO_LINEAR, is added (and declared in virtio_net
> as it's already capable of doing it). So consider implementing this
> in your drivers to greatly speed-up generic XSK xmit.

[...]
 
> ---------------- Performance Testing ------------
> 
> The test environment is Aliyun ECS server.
> Test cmd:
> ```
> xdpsock -i eth0 -t  -S -s <msg size>
> ```
> 
> Test result data:
> 
> size    64      512     1024    1500
> copy    1916747 1775988 1600203 1440054
> page    1974058 1953655 1945463 1904478
> percent 3.0%    10.0%   21.58%  32.3%
> 

For the series, but might be good to get Dave or Jakub to check
2/6 to be sure they agree.

Acked-by: John Fastabend <john.fastabend@gmail.com>