[net-next,v2,0/3] net: atlantic: Add XDP support

Message

Taehee Yoo March 19, 2022, 2:04 p.m. UTC

This patchset is to make atlantic to support multi-buffer XDP.

The first patch implement control plane of xdp.
The aq_xdp(), callback of .xdp_bpf is added.

The second patch implements data plane of xdp.
XDP_TX, XDP_DROP, and XDP_PASS is supported.
__aq_ring_xdp_clean() is added to receive and execute xdp program.
aq_nic_xmit_xdpf() is added to send packet by XDP.

The third patch implements callback of .ndo_xdp_xmit.
aq_xdp_xmit() is added to send redirected packets and it internally
calls aq_nic_xmit_xdpf().

Memory model is MEM_TYPE_PAGE_ORDER0 so it doesn't reuse rx page when
XDP_TX, XDP_PASS, XDP_REDIRECT.

Default the maximum rx frame size is 2K.
If xdp is attached, size is changed to about 3K.
It can be reused when XDP_DROP, XDP_ABORTED.

Atlantic driver has AQ_CFG_RX_PAGEORDER option and it will be always 0
if xdp is attached.

AQC chip supports 32 multi-queues and 8 vectors(irq).
There are two options.
1. under 8 cores and maximum 4 tx queues per core.
2. under 4 cores and maximum 8 tx queues per core.

Like other drivers, these tx queues can be used only for XDP_TX,
XDP_REDIRECT queue. If so, no tx_lock is needed.
But this patchset doesn't use this strategy because getting hardware tx
queue index cost is too high.
So, tx_lock is used in the aq_nic_xmit_xdpf().

single-core, single queue, 40% cpu utilization.

  30.75%  bpf_prog_xxx_xdp_prog_tx  [k] bpf_prog_xxx_xdp_prog_tx
  10.35%  [kernel]                  [k] aq_hw_read_reg <---------- here
   4.38%  [kernel]                  [k] get_page_from_freelist

single-core, 8 queues, 100% cpu utilization, half PPS.

  45.56%  [kernel]                  [k] aq_hw_read_reg <---------- here
  17.58%  bpf_prog_xxx_xdp_prog_tx  [k] bpf_prog_xxx_xdp_prog_tx
   4.72%  [kernel]                  [k] hw_atl_b0_hw_ring_rx_receive

Performance result(64 Byte)
1. XDP_TX
  a. xdp_geieric, single core
    - 2.5Mpps, 100% cpu
  b. xdp_driver, single core
    - 4.5Mpps, 40% cpu
  c. xdp_generic, 8 core(hyper thread)
    - 6.3Mpps, 5~10% cpu
  d. xdp_driver, 8 core(hyper thread)
    - 6.3Mpps, 5% cpu

2. XDP_REDIRECT
  a. xdp_generic, single core
    - 2.3Mpps
  b. xdp_driver, single core
    - 4.5Mpps

V2:
 - Do not use inline in C file

Taehee Yoo (3):
  net: atlantic: Implement xdp control plane
  net: atlantic: Implement xdp data plane
  net: atlantic: Implement .ndo_xdp_xmit handler

 .../net/ethernet/aquantia/atlantic/aq_cfg.h   |   1 +
 .../ethernet/aquantia/atlantic/aq_ethtool.c   |   8 +
 .../net/ethernet/aquantia/atlantic/aq_main.c  |  59 +++
 .../net/ethernet/aquantia/atlantic/aq_main.h  |   2 +
 .../net/ethernet/aquantia/atlantic/aq_nic.c   | 126 ++++--
 .../net/ethernet/aquantia/atlantic/aq_nic.h   |   7 +-
 .../net/ethernet/aquantia/atlantic/aq_ptp.c   |   2 +-
 .../net/ethernet/aquantia/atlantic/aq_ring.c  | 409 ++++++++++++++++--
 .../net/ethernet/aquantia/atlantic/aq_ring.h  |  17 +
 .../net/ethernet/aquantia/atlantic/aq_vec.c   |  23 +-
 .../net/ethernet/aquantia/atlantic/aq_vec.h   |   6 +
 .../aquantia/atlantic/hw_atl/hw_atl_a0.c      |   6 +-
 .../aquantia/atlantic/hw_atl/hw_atl_b0.c      |  10 +-
 13 files changed, 595 insertions(+), 81 deletions(-)