On 11/14/17 4:20 AM, Willem de Bruijn wrote:

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* Limit the scope of the first patchset to Rx only, and introduce Tx
  in a separate patchset.

all sounds good to me except above bit.
I don't remember people suggesting to split it this way.
What's the value of it without tx?

We definitely need Tx for our use-cases! I'll rephrase, so the
idea was making the initial patch set without Tx *driver*
specific code, e.g. use ndo_xdp_xmit/flush at a later point.

So AF_ZEROCOPY, the socket parts, would have Tx support.

@John Did I recall that correctly?

Yep, that is what I said. However, on second thought, without the
driver tx half I guess tx will be significantly slower.

The idea was that existing packet rings already send without
copying, so the benefit from device driver changes is not obvious.

I would leave them out for now and evaluate before possibly
sending a separate patchset.

are you suggesting to use new af_zerocopy for rx and old
af_packet for tx ? imo that's too cumbersome to use.
New interface has to be symmetrical from the start.