Re: [PATCH bpf-next 00/11] AF_XDP zero-copy support for i40e

["Björn Töpel" <bjorn.topel@gmail.com>]

Den tis 28 aug. 2018 kl 14:47 skrev Björn Töpel <bjorn.topel@gmail.com>:
>
> From: Björn Töpel <bjorn.topel@intel.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
>
>  drivers/net/ethernet/intel/i40e/Makefile      |   3 +-
>  drivers/net/ethernet/intel/i40e/i40e.h        |  19 +
>  drivers/net/ethernet/intel/i40e/i40e_main.c   | 307 ++++++-
>  drivers/net/ethernet/intel/i40e/i40e_txrx.c   | 182 ++--
>  drivers/net/ethernet/intel/i40e/i40e_txrx.h   |  20 +-
>  .../ethernet/intel/i40e/i40e_txrx_common.h    |  90 ++
>  drivers/net/ethernet/intel/i40e/i40e_xsk.c    | 834 ++++++++++++++++++
>  drivers/net/ethernet/intel/i40e/i40e_xsk.h    |  25 +
>  include/linux/netdevice.h                     |  26 +
>  include/net/xdp.h                             |   6 +-
>  include/net/xdp_sock.h                        |  43 +
>  net/core/xdp.c                                |  54 +-
>  net/xdp/xdp_umem.h                            |  10 -
>  samples/bpf/xdpsock_user.c                    |  12 +-
>  14 files changed, 1523 insertions(+), 108 deletions(-)
>  create mode 100644 drivers/net/ethernet/intel/i40e/i40e_txrx_common.h
>  create mode 100644 drivers/net/ethernet/intel/i40e/i40e_xsk.c
>  create mode 100644 drivers/net/ethernet/intel/i40e/i40e_xsk.h
>
> --
> 2.17.1
>

I was too quick on the trigger. Adding intel-wired-lan and JeffK.

@Jeff Apologies. :-(

Björn