Date:   Thu, 30 Aug 2018 11:05:52 +0200
From:   Björn Töpel <bjorn.topel@...il.com>
To:     Daniel Borkmann <daniel@...earbox.net>
Cc:     "Karlsson, Magnus" <magnus.karlsson@...el.com>,
        Magnus Karlsson <magnus.karlsson@...il.com>,
        "Duyck, Alexander H" <alexander.h.duyck@...el.com>,
        Alexander Duyck <alexander.duyck@...il.com>, ast@...nel.org,
        Jesper Dangaard Brouer <brouer@...hat.com>,
        Netdev <netdev@...r.kernel.org>,
        "Brandeburg, Jesse" <jesse.brandeburg@...el.com>,
        "Singhai, Anjali" <anjali.singhai@...el.com>,
        peter.waskiewicz.jr@...el.com,
        Björn Töpel <bjorn.topel@...el.com>,
        michael.lundkvist@...csson.com,
        Willem de Bruijn <willemdebruijn.kernel@...il.com>,
        John Fastabend <john.fastabend@...il.com>,
        Jakub Kicinski <jakub.kicinski@...ronome.com>,
        neerav.parikh@...el.com,
        MykytaI Iziumtsev <mykyta.iziumtsev@...aro.org>,
        Francois Ozog <francois.ozog@...aro.org>,
        Ilias Apalodimas <ilias.apalodimas@...aro.org>,
        Brian Brooks <brian.brooks@...aro.org>,
        William Tu <u9012063@...il.com>, pavel@...tnetmon.com,
        "Zhang, Qi Z" <qi.z.zhang@...el.com>
Subject: Re: [PATCH bpf-next 00/11] AF_XDP zero-copy support for i40e

Den ons 29 aug. 2018 kl 18:12 skrev Daniel Borkmann <daniel@...earbox.net>:
>
> On 08/28/2018 02:44 PM, Björn Töpel wrote:
> > From: Björn Töpel <bjorn.topel@...el.com>
> >
> > This patch set introduces zero-copy AF_XDP support for Intel's i40e
> > driver. In the first preparatory patch we also add support for
> > XDP_REDIRECT for zero-copy allocated frames so that XDP programs can
> > redirect them. This was a ToDo from the first AF_XDP zero-copy patch
> > set from early June. Special thanks to Alex Duyck and Jesper Dangaard
> > Brouer for reviewing earlier versions of this patch set.
> >
> > The i40e zero-copy code is located in its own file i40e_xsk.[ch]. Note
> > that in the interest of time, to get an AF_XDP zero-copy implementation
> > out there for people to try, some code paths have been copied from the
> > XDP path to the zero-copy path. It is out goal to merge the two paths
> > in later patch sets.
> >
> > In contrast to the implementation from beginning of June, this patch
> > set does not require any extra HW queues for AF_XDP zero-copy
> > TX. Instead, the XDP TX HW queue is used for both XDP_REDIRECT and
> > AF_XDP zero-copy TX.
> >
> > Jeff, given that most of changes are in i40e, it is up to you how you
> > would like to route these patches. The set is tagged bpf-next, but
> > if taking it via the Intel driver tree is easier, let us know.
> >
> > We have run some benchmarks on a dual socket system with two Broadwell
> > E5 2660 @ 2.0 GHz with hyperthreading turned off. Each socket has 14
> > cores which gives a total of 28, but only two cores are used in these
> > experiments. One for TR/RX and one for the user space application. The
> > memory is DDR4 @ 2133 MT/s (1067 MHz) and the size of each DIMM is
> > 8192MB and with 8 of those DIMMs in the system we have 64 GB of total
> > memory. The compiler used is gcc (Ubuntu 7.3.0-16ubuntu3) 7.3.0. The
> > NIC is Intel I40E 40Gbit/s using the i40e driver.
> >
> > Below are the results in Mpps of the I40E NIC benchmark runs for 64
> > and 1500 byte packets, generated by a commercial packet generator HW
> > outputing packets at full 40 Gbit/s line rate. The results are with
> > retpoline and all other spectre and meltdown fixes, so these results
> > are not comparable to the ones from the zero-copy patch set in June.
> >
> > AF_XDP performance 64 byte packets.
> > Benchmark   XDP_SKB    XDP_DRV    XDP_DRV with zerocopy
> > rxdrop       2.6        8.2         15.0
> > txpush       2.2        -           21.9
> > l2fwd        1.7        2.3         11.3
> >
> > AF_XDP performance 1500 byte packets:
> > Benchmark   XDP_SKB   XDP_DRV     XDP_DRV with zerocopy
> > rxdrop       2.0        3.3         3.3
> > l2fwd        1.3        1.7         3.1
> >
> > XDP performance on our system as a base line:
> >
> > 64 byte packets:
> > XDP stats       CPU     pps         issue-pps
> > XDP-RX CPU      16      18.4M  0
> >
> > 1500 byte packets:
> > XDP stats       CPU     pps         issue-pps
> > XDP-RX CPU      16      3.3M    0
> >
> > The structure of the patch set is as follows:
> >
> > Patch 1: Add support for XDP_REDIRECT of zero-copy allocated frames
> > Patches 2-4: Preparatory patches to common xsk and net code
> > Patches 5-7: Preparatory patches to i40e driver code for RX
> > Patch 8: i40e zero-copy support for RX
> > Patch 9: Preparatory patch to i40e driver code for TX
> > Patch 10: i40e zero-copy support for TX
> > Patch 11: Add flags to sample application to force zero-copy/copy mode
> >
> > We based this patch set on bpf-next commit 050cdc6c9501 ("Merge
> > git://git.kernel.org/pub/scm/linux/kernel/git/davem/net")
> >
> >
> > Magnus & Björn
> >
> > Björn Töpel (8):
> >   xdp: implement convert_to_xdp_frame for MEM_TYPE_ZERO_COPY
> >   xdp: export xdp_rxq_info_unreg_mem_model
> >   xsk: expose xdp_umem_get_{data,dma} to drivers
> >   i40e: added queue pair disable/enable functions
> >   i40e: refactor Rx path for re-use
> >   i40e: move common Rx functions to i40e_txrx_common.h
> >   i40e: add AF_XDP zero-copy Rx support
> >   samples/bpf: add -c/--copy -z/--zero-copy flags to xdpsock
> >
> > Magnus Karlsson (3):
> >   net: add napi_if_scheduled_mark_missed
> >   i40e: move common Tx functions to i40e_txrx_common.h
> >   i40e: add AF_XDP zero-copy Tx support
>
> Thanks for working on this, LGTM! Are you also planning to get ixgbe
> out after that?
>

Yes, the plan is to get ixgbe out as the next driver, but we'll focus
on the existing i40e issues first.


Thanks,
Björn

> For the series:
>
> Acked-by: Daniel Borkmann <daniel@...earbox.net>
>
> Thanks,
> Daniel

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