[PATCH v4 net-next 00/15] net: fec: improve XDP copy mode and add AF_XDP zero-copy support

Wei Fang
2026-01-23T02:22:09Z

This patch set optimizes the XDP copy mode logic as follows.

1. Separate the processing of RX XDP frames from fec_enet_rx_queue(),
and adds a separate function fec_enet_rx_queue_xdp() for handling XDP
frames.

2. For TX XDP packets, using the batch sending method to avoid frequent
MMIO writes.

3. Use the switch statement to check the tx_buf type instead of the
if...else... statement, making the cleanup logic of TX BD ring cleared
and more efficient.

We compared the performance of XDP copy mode before and after applying
this patch set, and the results show that the performance has improved.

Before applying this patch set.
root@imx93evk:~# ./xdp-bench tx eth0
Summary 396,868 rx/s 0 err,drop/s
Summary 396,024 rx/s 0 err,drop/s

root@imx93evk:~# ./xdp-bench drop eth0
Summary 684,781 rx/s 0 err/s
Summary 675,746 rx/s 0 err/s

root@imx93evk:~# ./xdp-bench pass eth0
Summary 208,552 rx/s 0 err,drop/s
Summary 208,654 rx/s 0 err,drop/s

root@imx93evk:~# ./xdp-bench redirect eth0 eth0
eth0->eth0 311,210 rx/s 0 err,drop/s 311,208 xmit/s
eth0->eth0 310,808 rx/s 0 err,drop/s 310,809 xmit/s

After applying this patch set.
root@imx93evk:~# ./xdp-bench tx eth0
Summary 425,778 rx/s 0 err,drop/s
Summary 426,042 rx/s 0 err,drop/s

root@imx93evk:~# ./xdp-bench drop eth0
Summary 698,351 rx/s 0 err/s
Summary 701,882 rx/s 0 err/s

root@imx93evk:~# ./xdp-bench pass eth0
Summary 210,348 rx/s 0 err,drop/s
Summary 210,016 rx/s 0 err,drop/s

root@imx93evk:~# ./xdp-bench redirect eth0 eth0
eth0->eth0 354,407 rx/s 0 err,drop/s 354,401 xmit/s
eth0->eth0 350,381 rx/s 0 err,drop/s 350,389 xmit/s

This patch set also addes the AF_XDP zero-copy support, and we tested
the performance on i.MX93 platform with xdpsock tool. The following is
the performance comparison of copy mode and zero-copy mode. It can be
seen that the performance of zero-copy mode is better than that of copy
mode.

1. MAC swap L2 forwarding
1.1 Zero-copy mode
root@imx93evk:~# ./xdpsock -i eth0 -l -z
sock0@eth0:0 l2fwd xdp-drv
pps pkts 1.00
rx 414715 415455
tx 414715 415455

1.2 Copy mode
root@imx93evk:~# ./xdpsock -i eth0 -l -c
sock0@eth0:0 l2fwd xdp-drv
pps pkts 1.00
rx 356396 356609
tx 356396 356609

2. TX only
2.1 Zero-copy mode
root@imx93evk:~# ./xdpsock -i eth0 -t -s 64 -z
sock0@eth0:0 txonly xdp-drv
pps pkts 1.00
rx 0 0
tx 1119573 1126720

2.2 Copy mode
root@imx93evk:~# ./xdpsock -i eth0 -t -s 64 -c
sock0@eth0:0 txonly xdp-drv
pps pkts 1.00
rx 0 0
tx 406864 407616

---
v4:
1. Remove the unneeded semicolon in fec_enet_bd_init()
v3 link: https://lore.kernel.org/imx/20260121033357.3261464-1-wei.fang@nxp.com/
v3:
1. Fix build warning due to missing break for the FEC_TXBUF_T_XSK_TX
branch in fec_enet_bd_init().
2. Add new patch 7, which is separated from patch 6
3. Collect Reviewed-by tags.
v2 link: https://lore.kernel.org/imx/20260116074027.1603841-1-wei.fang@nxp.com/
v2:
1. Improve the commit message
2. Remove the unused variable dma from fec_enet_rx_queue_xsk() to fix
the build warning
3. Remove fec_txq_trigger_xmit() from fec_enet_xsk_tx_xmit()
4. Separate some new patches, patch 4, 8, 13.
5. Collect Reviewed-by tags.
vl link: https://lore.kernel.org/imx/20260113032939.3705137-1-wei.fang@nxp.com/
---

Wei Fang (15):
net: fec: add fec_txq_trigger_xmit() helper
net: fec: add fec_rx_error_check() to check RX errors
net: fec: add rx_shift to indicate the extra bytes padded in front of
RX frame
net: fec: add fec_build_skb() to build a skb
net: fec: improve fec_enet_rx_queue()
net: fec: add fec_enet_rx_queue_xdp() for XDP path
net: fec: add tx_qid parameter to fec_enet_xdp_tx_xmit()
net: fec: transmit XDP frames in bulk
net: fec: remove unnecessary NULL pointer check when clearing TX BD
ring
net: fec: use switch statement to check the type of tx_buf
net: fec: remove the size parameter from fec_enet_create_page_pool()
net: fec: move xdp_rxq_info* APIs out of fec_enet_create_page_pool()
net: fec: add fec_alloc_rxq_buffers_pp() to allocate buffers from page
pool
net: fec: improve fec_enet_tx_queue()
net: fec: add AF_XDP zero-copy support

drivers/net/ethernet/freescale/fec.h | 14 +-
drivers/net/ethernet/freescale/fec_main.c | 1454 +++++++++++++++------
2 files changed, 1079 insertions(+), 389 deletions(-)

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2.34.1