netdev - Re: [PATCH net-next v2 0/9] xsk: improvement performance in copy mode

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Message-ID: <CAL+tcoDNbi1yFaH=VpZhXKM4HtMR4S+==UweXzWzCbsXMOpnSQ@mail.gmail.com>
Date: Tue, 26 Aug 2025 09:49:11 +0800
From: Jason Xing <kerneljasonxing@...il.com>
To: Jakub Kicinski <kuba@...nel.org>
Cc: davem@...emloft.net, edumazet@...gle.com, pabeni@...hat.com, 
	bjorn@...nel.org, magnus.karlsson@...el.com, maciej.fijalkowski@...el.com, 
	jonathan.lemon@...il.com, sdf@...ichev.me, ast@...nel.org, 
	daniel@...earbox.net, hawk@...nel.org, john.fastabend@...il.com, 
	horms@...nel.org, andrew+netdev@...n.ch, bpf@...r.kernel.org, 
	netdev@...r.kernel.org, Jason Xing <kernelxing@...cent.com>
Subject: Re: [PATCH net-next v2 0/9] xsk: improvement performance in copy mode

On Tue, Aug 26, 2025 at 9:15 AM Jakub Kicinski <kuba@...nel.org> wrote:
>
> On Tue, 26 Aug 2025 08:51:24 +0800 Jason Xing wrote:
> > > > Sorry for missing the question. I'm not very familiar with how to run the
> > > > test based on AF_PACKET. Could you point it out for me? Thanks.
> > > >
> > > > I remember the very initial version of AF_XDP was pure AF_PACKET. So
> > > > may I ask why we expect to see the comparison between them?
> > >
> > > Pretty sure I told you this at least twice but the point of AF_XDP
> > > is the ZC mode. Without a comparison to AF_PACKET which has similar
> > > functionality optimizing AF_XDP copy mode seems unjustified.
> >
> > Oh, I see. Let me confirm again that you expect to see a demo like the
> > copy mode of AF_PACKET v4 [1] and see the differences in performance,
> > right?
> >
> > If AF_PACKET eventually outperforms AF_XDP, do we need to reinvent the
> > copy mode based on AF_PACKET?
> >
> > And if a quick/simple implementation is based on AF_PACKET, it
> > shouldn't be that easy to use the same benchmark to see which one is
> > better. That means inventing a new unified benchmark tool is
> > necessary?
>
> To be honest I suspect you can get an LLM to convert your AF_XDP test
> to use AF_PACKET..

Okay, allow me to spend more time on af_packet before getting my hands
dirty... Converting xdpsock should not be that easy, I feel... But I
will give it a try first.

Thanks,
Jason