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From: Jesper Dangaard Brouer <brouer@redhat.com>
To: Florian Westphal <fw@strlen.de>
Cc: brouer@redhat.com, netdev@vger.kernel.org
Subject: Re: [flamebait] xdp, well meaning but pointless
Date: Fri, 2 Dec 2016 18:22:33 +0100	[thread overview]
Message-ID: <20161202182233.7d78459f@redhat.com> (raw)
In-Reply-To: <20161201091108.GF26507@breakpoint.cc>


On Thu, 1 Dec 2016 10:11:08 +0100 Florian Westphal <fw@strlen.de> wrote:

> In light of DPDKs existence it make a lot more sense to me to provide
> a). a faster mmap based interface (possibly AF_PACKET based) that allows
> to map nic directly into userspace, detaching tx/rx queue from kernel.
> 
> John Fastabend sent something like this last year as a proof of
> concept, iirc it was rejected because register space got exposed directly
> to userspace.  I think we should re-consider merging netmap
> (or something conceptually close to its design).

I'm actually working in this direction, of zero-copy RX mapping packets
into userspace.  This work is mostly related to page_pool, and I only
plan to use XDP as a filter for selecting packets going to userspace,
as this choice need to be taken very early.

My design is here:
 https://prototype-kernel.readthedocs.io/en/latest/vm/page_pool/design/memory_model_nic.html

This is mostly about changing the memory model in the drivers, to allow
for safely mapping pages to userspace.  (An efficient queue mechanism is
not covered).  People often overlook that netmap's efficiency *also* comes
from introducing pre-mapping memory/pages to userspace.

-- 
Best regards,
  Jesper Dangaard Brouer
  MSc.CS, Principal Kernel Engineer at Red Hat
  LinkedIn: http://www.linkedin.com/in/brouer

  parent reply	other threads:[~2016-12-02 17:23 UTC|newest]

Thread overview: 40+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-12-01  9:11 [flamebait] xdp, well meaning but pointless Florian Westphal
2016-12-01 13:42 ` Hannes Frederic Sowa
2016-12-01 14:58 ` Thomas Graf
2016-12-01 15:52   ` Hannes Frederic Sowa
2016-12-01 16:28     ` Thomas Graf
2016-12-01 20:44       ` Hannes Frederic Sowa
2016-12-01 21:12         ` Tom Herbert
2016-12-01 21:27           ` Hannes Frederic Sowa
2016-12-01 21:51             ` Tom Herbert
2016-12-02 10:24               ` Jesper Dangaard Brouer
2016-12-02 11:54                 ` Hannes Frederic Sowa
2016-12-02 16:59                   ` Tom Herbert
2016-12-02 18:12                     ` Hannes Frederic Sowa
2016-12-02 19:56                       ` Stephen Hemminger
2016-12-02 20:19                         ` Tom Herbert
2016-12-02 18:39             ` bpf bounded loops. Was: [flamebait] xdp Alexei Starovoitov
2016-12-02 19:25               ` Hannes Frederic Sowa
2016-12-02 19:42                 ` John Fastabend
2016-12-02 19:50                   ` Hannes Frederic Sowa
2016-12-03  0:20                   ` Alexei Starovoitov
2016-12-03  9:11                     ` Sargun Dhillon
2016-12-02 19:42                 ` Hannes Frederic Sowa
2016-12-02 23:34                   ` Alexei Starovoitov
2016-12-04 16:05                     ` [flamebait] xdp Was: " Hannes Frederic Sowa
2016-12-06  3:05                       ` Alexei Starovoitov
2016-12-06  5:08                         ` Tom Herbert
2016-12-06  6:04                           ` Alexei Starovoitov
2016-12-05 16:40                 ` Edward Cree
2016-12-05 16:50                   ` Hannes Frederic Sowa
2016-12-05 16:54                     ` Edward Cree
2016-12-06 11:35                       ` Hannes Frederic Sowa
2016-12-01 16:06   ` [flamebait] xdp, well meaning but pointless Florian Westphal
2016-12-01 16:19   ` David Miller
2016-12-01 16:51     ` Florian Westphal
2016-12-01 17:20     ` Hannes Frederic Sowa
     [not found] ` <CALx6S35R_ZStV=DbD-7Gf_y5xXqQq113_6m5p-p0GQfv46v0Ow@mail.gmail.com>
2016-12-01 18:02   ` Tom Herbert
2016-12-02 17:22 ` Jesper Dangaard Brouer [this message]
2016-12-03 16:19   ` Willem de Bruijn
2016-12-03 19:48     ` John Fastabend
2016-12-05 11:04       ` Jesper Dangaard Brouer

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