[PATCH net-next 0/5] net/mlx5e: XDP, Add support for multi-packet per page

[Tariq Toukan]

This change removes the limitation of having one packet per page in XDP
mode. This has the following implications:

- XDP in Striding RQ mode can now be used on 64K page systems.

- XDP in Legacy RQ mode was using a single packet per page which on 64K
  page systems is quite inefficient. The improvement can be observed
  with an XDP_DROP test when running in Legacy RQ mode on a ARM
  Neoverse-N1 system with a 64K page size:
  +-----------------------------------------------+
  | MTU  | baseline   | this change | improvement |
  |------+------------+-------------+-------------|
  | 1500 | 15.55 Mpps | 18.99 Mpps  | 22.0 %      |
  | 9000 | 15.53 Mpps | 18.24 Mpps  | 17.5 %      |
  +-----------------------------------------------+

After lifting this limitation, the series switches to using fragments
for the side page in non-linear mode. This small improvement is at most
visible for XDP_DROP tests with small 64B packets and a large enough MTU
for Striding RQ to be in non-linear mode:
+----------------------------------------------------------------------+
| System               | MTU  | baseline   | this change | improvement |
|----------------------+------+------------+-------------+-------------|
| 4K page x86_64 [1]   | 9000 | 26.30 Mpps | 30.45 Mpps  | 15.80 %     |
| 64K page aarch64 [2] | 9000 | 15.27 Mpps | 20.10 Mpps  | 31.62 %     |
+----------------------------------------------------------------------+

This series does not cover the xsk (AF_XDP) paths for 64K page systems.


Dragos Tatulea (5):
  net/mlx5e: XSK, Increase size for chunk_size param
  net/mlx5e: XDP, Improve dma address calculation of linear part for
    XDP_TX
  net/mlx5e: XDP, Remove stride size limitation
  net/mlx5e: XDP, Use a single linear page per rq
  net/mlx5e: XDP, Use page fragments for linear data in multibuf-mode

 drivers/net/ethernet/mellanox/mlx5/core/en.h  | 12 +++-
 .../ethernet/mellanox/mlx5/core/en/params.c   | 11 +---
 .../ethernet/mellanox/mlx5/core/en/params.h   |  2 +-
 .../net/ethernet/mellanox/mlx5/core/en/xdp.c  |  2 +-
 .../net/ethernet/mellanox/mlx5/core/en_main.c | 50 ++++++++++++++--
 .../net/ethernet/mellanox/mlx5/core/en_rx.c   | 59 +++++++++++++++----
 6 files changed, 107 insertions(+), 29 deletions(-)


base-commit: a7fb05cbb8f989fa5a81818be9680464cff9d717
-- 
2.44.0