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From: Jesper Dangaard Brouer <brouer@redhat.com>
To: "Björn Töpel" <bjorn.topel@gmail.com>
Cc: "Willem de Bruijn" <willemdebruijn.kernel@gmail.com>,
	"Alexei Starovoitov" <ast@fb.com>,
	"John Fastabend" <john.fastabend@gmail.com>,
	"Karlsson, Magnus" <magnus.karlsson@intel.com>,
	"Duyck, Alexander H" <alexander.h.duyck@intel.com>,
	"Alexander Duyck" <alexander.duyck@gmail.com>,
	michael.lundkvist@ericsson.com, ravineet.singh@ericsson.com,
	"Daniel Borkmann" <daniel@iogearbox.net>,
	Netdev <netdev@vger.kernel.org>,
	"Tushar Dave" <tushar.n.dave@oracle.com>,
	"Eric Dumazet" <eric.dumazet@gmail.com>,
	"Björn Töpel" <bjorn.topel@intel.com>,
	"Brandeburg, Jesse" <jesse.brandeburg@intel.com>,
	"Singhai, Anjali" <anjali.singhai@intel.com>,
	"Rosen, Rami" <rami.rosen@intel.com>,
	"Shaw, Jeffrey B" <jeffrey.b.shaw@intel.com>,
	"Yigit, Ferruh" <ferruh.yigit@intel.com>
Subject: Re: [RFC PATCH 00/14] Introducing AF_PACKET V4 support
Date: Thu, 16 Nov 2017 09:26:15 +0100	[thread overview]
Message-ID: <20171116092615.3581d368@redhat.com> (raw)
In-Reply-To: <CAJ+HfNgeJXUgdCqzA7OU8RwQxRb7optZyhTApobHKezUDoSf9Q@mail.gmail.com>


On Thu, 16 Nov 2017 08:09:04 +0100 Björn Töpel <bjorn.topel@gmail.com> wrote:

> Ideally, it would be best not having to introduce yet another xmit
> ndo. I believe ndo_xdp_xmit/ndo_xdp_flush would be the best fit, but
> we need to extend it with a destructor callback and potentially some
> kind of DMA trait. Why DMA? For zerocopy, we know the working set of
> packet buffers, so they are DMA mapped up front, whereas ndo_xdp_xmit
> does yet another DMA mapping. Paying for the DMA mapping in the
> fast-path is something we'd like to avoid.

I like your idea of reusing ndo_xdp_xmit/ndo_xdp_flush.  At NetConf I
think we agreed that the ndo_xdp_xmit API likely need to change. See[1]
slide 11.  Andy Gospodarek and Michael Chan wanted to look into the
needed API changes (Cc'ed) thus, lets keep them in the loop.

I also appreciate that you are thinking about avoiding the DMA-mapping
at TX.  It would be a welcomed optimization.

[1] http://people.netfilter.org/hawk/presentations/NetConf2017_Seoul/XDP_devel_update_NetConf2017_Seoul.pdf
-- 
Best regards,
  Jesper Dangaard Brouer
  MSc.CS, Principal Kernel Engineer at Red Hat
  LinkedIn: http://www.linkedin.com/in/brouer

  reply	other threads:[~2017-11-16  8:26 UTC|newest]

Thread overview: 49+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-10-31 12:41 [RFC PATCH 00/14] Introducing AF_PACKET V4 support Björn Töpel
2017-10-31 12:41 ` [RFC PATCH 01/14] packet: introduce AF_PACKET V4 userspace API Björn Töpel
2017-11-02  1:45   ` Willem de Bruijn
2017-11-02 10:06     ` Björn Töpel
2017-11-02 16:40       ` Tushar Dave
2017-11-02 16:47         ` Björn Töpel
2017-11-03  2:29       ` Willem de Bruijn
2017-11-03  9:54         ` Björn Töpel
2017-11-15 22:21           ` chet l
2017-11-16 16:53             ` Jesper Dangaard Brouer
2017-11-17  3:32               ` chetan L
2017-11-15 22:34   ` chet l
2017-11-16  1:44     ` David Miller
2017-11-16 19:32       ` chetan L
2017-10-31 12:41 ` [RFC PATCH 02/14] packet: implement PACKET_MEMREG setsockopt Björn Töpel
2017-11-03  3:00   ` Willem de Bruijn
2017-11-03  9:57     ` Björn Töpel
2017-10-31 12:41 ` [RFC PATCH 03/14] packet: enable AF_PACKET V4 rings Björn Töpel
2017-11-03  4:16   ` Willem de Bruijn
2017-11-03 10:02     ` Björn Töpel
2017-10-31 12:41 ` [RFC PATCH 04/14] packet: enable Rx for AF_PACKET V4 Björn Töpel
2017-10-31 12:41 ` [RFC PATCH 05/14] packet: enable Tx support " Björn Töpel
2017-10-31 12:41 ` [RFC PATCH 06/14] netdevice: add AF_PACKET V4 zerocopy ops Björn Töpel
2017-10-31 12:41 ` [RFC PATCH 07/14] packet: wire up zerocopy for AF_PACKET V4 Björn Töpel
2017-11-03  3:17   ` Willem de Bruijn
2017-11-03 10:47     ` Björn Töpel
2017-10-31 12:41 ` [RFC PATCH 08/14] i40e: AF_PACKET V4 ndo_tp4_zerocopy Rx support Björn Töpel
2017-10-31 12:41 ` [RFC PATCH 09/14] i40e: AF_PACKET V4 ndo_tp4_zerocopy Tx support Björn Töpel
2017-10-31 12:41 ` [RFC PATCH 10/14] samples/tpacket4: added tpbench Björn Töpel
2017-10-31 12:41 ` [RFC PATCH 11/14] veth: added support for PACKET_ZEROCOPY Björn Töpel
2017-10-31 12:41 ` [RFC PATCH 12/14] samples/tpacket4: added veth support Björn Töpel
2017-10-31 12:41 ` [RFC PATCH 13/14] i40e: added XDP support for TP4 enabled queue pairs Björn Töpel
2017-10-31 12:41 ` [RFC PATCH 14/14] xdp: introducing XDP_PASS_TO_KERNEL for PACKET_ZEROCOPY use Björn Töpel
2017-11-03  4:34 ` [RFC PATCH 00/14] Introducing AF_PACKET V4 support Willem de Bruijn
2017-11-03 10:13   ` Karlsson, Magnus
2017-11-03 13:55     ` Willem de Bruijn
2017-11-13 13:07 ` Björn Töpel
2017-11-13 14:34   ` John Fastabend
2017-11-13 23:50   ` Alexei Starovoitov
2017-11-14  5:33     ` Björn Töpel
2017-11-14  7:02       ` John Fastabend
2017-11-14 12:20         ` Willem de Bruijn
2017-11-16  2:55           ` Alexei Starovoitov
2017-11-16  3:35             ` Willem de Bruijn
2017-11-16  7:09               ` Björn Töpel
2017-11-16  8:26                 ` Jesper Dangaard Brouer [this message]
2017-11-14 17:19   ` [RFC PATCH 00/14] Introducing AF_PACKET V4 support (AF_XDP or AF_CHANNEL?) Jesper Dangaard Brouer
2017-11-14 19:01     ` Björn Töpel
2017-11-16  8:00       ` Jesper Dangaard Brouer

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