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Date:   Wed, 31 Mar 2021 12:01:27 +0000
To:     Magnus Karlsson <magnus.karlsson@gmail.com>
From:   Alexander Lobakin <alobakin@pm.me>
Cc:     Alexander Lobakin <alobakin@pm.me>,
        Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Xuan Zhuo <xuanzhuo@linux.alibaba.com>,
        =?utf-8?Q?Bj=C3=B6rn_T=C3=B6pel?= <bjorn@kernel.org>,
        Magnus Karlsson <magnus.karlsson@intel.com>,
        Jonathan Lemon <jonathan.lemon@gmail.com>,
        "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        Jesper Dangaard Brouer <hawk@kernel.org>,
        John Fastabend <john.fastabend@gmail.com>,
        Andrii Nakryiko <andrii@kernel.org>,
        Martin KaFai Lau <kafai@fb.com>,
        Song Liu <songliubraving@fb.com>, Yonghong Song <yhs@fb.com>,
        KP Singh <kpsingh@kernel.org>,
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Reply-To: Alexander Lobakin <alobakin@pm.me>
Subject: Re: [PATCH bpf-next 0/2] xsk: introduce generic almost-zerocopy xmit
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From: Magnus Karlsson <magnus.karlsson@gmail.com>
Date: Wed, 31 Mar 2021 11:44:45 +0200

> On Wed, Mar 31, 2021 at 1:17 AM Alexander Lobakin <alobakin@pm.me> wrote:
> >
> > This series is based on the exceptional generic zerocopy xmit logics
> > initially introduced by Xuan Zhuo. It extends it the way that it
> > could cover all the sane drivers, not only the ones that are capable
> > of xmitting skbs with no linear space.
> >
> > The first patch is a random while-we-are-here improvement over
> > full-copy path, and the second is the main course. See the individual
> > commit messages for the details.
> >
> > The original (full-zerocopy) path is still here and still generally
> > faster, but for now it seems like virtio_net will remain the only
> > user of it, at least for a considerable period of time.
> >
> > Alexander Lobakin (2):
> >   xsk: speed-up generic full-copy xmit
> >   xsk: introduce generic almost-zerocopy xmit
> >
> >  net/xdp/xsk.c | 33 +++++++++++++++++++++++----------
> >  1 file changed, 23 insertions(+), 10 deletions(-)
> >
> > --
> > Well, this is untested. I currently don't have an access to my setup
> > and is bound by moving to another country, but as I don't know for
> > sure at the moment when I'll get back to work on the kernel next time,
> > I found it worthy to publish this now -- if any further changes will
> > be required when I already will be out-of-sight, maybe someone could
> > carry on to make a another revision and so on (I'm still here for any
> > questions, comments, reviews and improvements till the end of this
> > week).
> > But this *should* work with all the sane drivers. If a particular
> > one won't handle this, it's likely ill.
>
> Thanks Alexander. I will take your patches for a spin on a couple of
> NICs and get back to you, though it will be next week due to holidays
> where I am based.

Thanks a lot! Any tests will be much appreciated.
I'll publish v2 in a moment though, want to drop a couple of
micro-optimizations.

> > --
> > 2.31.1

Al