[PATCH v2 0/5] Introducing ixgbe AF_XDP ZC support

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

From: Björn Töpel <bjorn.topel@intel.com>

Jeff: Please remove the v1 patches from your dev-queue!

This patch set introduces zero-copy AF_XDP support for Intel's ixgbe
driver.

The ixgbe zero-copy code is located in its own file ixgbe_xsk.[ch],
analogous to the i40e ZC support. Again, as in i40e, code paths have
been copied from the XDP path to the zero-copy path. Going forward we
will try to generalize more code between the AF_XDP ZC drivers, and
also reduce the heavy C&P.

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 7.3.0. The NIC is Intel
82599ES/X520-2 10Gbit/s using the ixgbe driver.

Below are the results in Mpps of the 82599ES/X520-2 NIC benchmark runs
for 64B and 1500B packets, generated by a commercial packet generator
HW blasting packets at full 10Gbit/s line rate. The results are with
retpoline and all other spectre and meltdown fixes.

AF_XDP performance 64B packets:
Benchmark   XDP_DRV with zerocopy
rxdrop        14.7
txpush        14.6
l2fwd         11.1

AF_XDP performance 1500B packets:
Benchmark   XDP_DRV with zerocopy
rxdrop        0.8
l2fwd         0.8

XDP performance on our system as a base line.

64B packets:
XDP stats       CPU     Mpps       issue-pps
XDP-RX CPU      16      14.7       0

1500B packets:
XDP stats       CPU     Mpps       issue-pps
XDP-RX CPU      16      0.8        0

The structure of the patch set is as follows:

Patch 1: Introduce Rx/Tx ring enable/disable functionality
Patch 2: Preparatory patche to ixgbe driver code for RX
Patch 3: ixgbe zero-copy support for RX
Patch 4: Preparatory patch to ixgbe driver code for TX
Patch 5: ixgbe zero-copy support for TX

Changes since v1:

* Removed redundant AF_XDP precondition checks, pointed out by
  Jakub. Now, the preconditions are only checked at XDP enable time.
* Fixed a crash in the egress path, due to incorrect usage of
  ixgbe_ring queue_index member. In v2 a ring_idx back reference is
  introduced, and used in favor of queue_index. William reported the
  crash, and helped me smoke out the issue. Kudos!
* In ixgbe_xsk_async_xmit, validate qid against num_xdp_queues,
  instead of num_rx_queues.

Cheers!
Björn

Björn Töpel (5):
  ixgbe: added Rx/Tx ring disable/enable functions
  ixgbe: move common Rx functions to ixgbe_txrx_common.h
  ixgbe: add AF_XDP zero-copy Rx support
  ixgbe: move common Tx functions to ixgbe_txrx_common.h
  ixgbe: add AF_XDP zero-copy Tx support

 drivers/net/ethernet/intel/ixgbe/Makefile     |   3 +-
 drivers/net/ethernet/intel/ixgbe/ixgbe.h      |  28 +-
 drivers/net/ethernet/intel/ixgbe/ixgbe_lib.c  |  17 +-
 drivers/net/ethernet/intel/ixgbe/ixgbe_main.c | 291 ++++++-
 .../ethernet/intel/ixgbe/ixgbe_txrx_common.h  |  50 ++
 drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c  | 803 ++++++++++++++++++
 6 files changed, 1146 insertions(+), 46 deletions(-)
 create mode 100644 drivers/net/ethernet/intel/ixgbe/ixgbe_txrx_common.h
 create mode 100644 drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c

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2.17.1