Re: [PATCH net-next v9 0/3] Add minimal XDP support to TI AM65 CPSW Ethernet driver

[Roger Quadros <rogerq@kernel.org>]

Hello Julien,

On 12/04/2024 18:38, Julien Panis wrote:
> This patch adds XDP support to TI AM65 CPSW Ethernet driver.
> 
> The following features are implemented: NETDEV_XDP_ACT_BASIC,
> NETDEV_XDP_ACT_REDIRECT, and NETDEV_XDP_ACT_NDO_XMIT.
> 
> Zero-copy and non-linear XDP buffer supports are NOT implemented.
> 
> Besides, the page pool memory model is used to get better performance.
> 
> Signed-off-by: Julien Panis <jpanis@baylibre.com>

I've been trying to test this since I don't want my RX multi queue series [1]
to break AF_XDP feature. However, with 6.10 I don't see AF_XDP working at all
and even breaking basic networking on am65-cpsw.

The in kernel XDP tests have been dropped so I've been using xdp-tools [2]

My test is to try XDP_DROP with xdp-bench using skb mode first and then
native XDP mode.

Below is the test log. You can see that skb mode works fine. The moment I try
native XDP mode the interface seems to go down and up and then just locks up.

I can no longer ping to the remote host.

----test log starts-----

root@am64xx-evm:~/xdp-tools/xdp-bench# ping 192.168.1.36
PING 192.168.1.36 (192.168.1.36) 56(84) bytes of data.
64 bytes from 192.168.1.36: icmp_seq=1 ttl=64 time=0.801 ms
64 bytes from 192.168.1.36: icmp_seq=2 ttl=64 time=0.967 ms
64 bytes from 192.168.1.36: icmp_seq=3 ttl=64 time=0.876 ms
^C
--- 192.168.1.36 ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 2003ms
rtt min/avg/max/mdev = 0.801/0.881/0.967/0.067 ms


root@am64xx-evm:~/xdp-tools/xdp-bench# ./xdp-bench drop -m skb eth0
Dropping packets on eth0 (ifindex 2; driver am65-cpsw-nuss)
Summary                     81127 rx/s                  0 err/s        
Summary                     81088 rx/s                  0 err/s        
Summary                     81089 rx/s                  0 err/s        
Summary                     53065 rx/s                  0 err/s        
^C
  Packets received    : 296369    
  Average packets/s   : 74092     
  Rx dropped          : 296369    

root@am64xx-evm:~/xdp-tools/xdp-bench# ping 192.168.1.36
PING 192.168.1.36 (192.168.1.36) 56(84) bytes of data.
64 bytes from 192.168.1.36: icmp_seq=1 ttl=64 time=1.02 ms
64 bytes from 192.168.1.36: icmp_seq=2 ttl=64 time=0.756 ms
64 bytes from 192.168.1.36: icmp_seq=3 ttl=64 time=0.963 ms
^C
--- 192.168.1.36 ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 2003ms
rtt min/avg/max/mdev = 0.756/0.914/1.024/0.114 ms


root@am64xx-evm:~/xdp-tools/xdp-bench# ./xdp-bench drop -m native eth0
[  889.096851] am65-cpsw-nuss 8000000.ethernet eth0: Link is Down
[  889.110889] am65-cpsw-nuss 8000000.ethernet eth0: PHY [8000f00.mdio:00] driver [TI DP83867] (irq=POLL)
[  889.120377] am65-cpsw-nuss 8000000.ethernet eth0: configuring for phy/rgmii-rxid link mode
Dropping packets on eth0 (ifindex 2; driver am65-cpsw-nuss)
Summary                         0 rx/s                  0 err/s        
Summary                         0 rx/s                  0 err/s        
[  893.218318] am65-cpsw-nuss 8000000.ethernet eth0: Link is Up - 1Gbps/Full - flow control rx/tx
Summary                       250 rx/s                  0 err/s        
Summary                         0 rx/s                  0 err/s        
Summary                         0 rx/s                  0 err/s        
Summary                         0 rx/s                  0 err/s        
^C
[  901.898170] am65-cpsw-nuss 8000000.ethernet eth0: Link is Down
[  901.910292] am65-cpsw-nuss 8000000.ethernet eth0: PHY [8000f00.mdio:00] driver [TI DP83867] (irq=POLL)
[  901.919661] am65-cpsw-nuss 8000000.ethernet eth0: configuring for phy/rgmii-rxid link mode
  Packets received    : 250       
  Average packets/s   : 42        
  Rx dropped          : 250       
root@am64xx-evm:~/xdp-tools/xdp-bench# [  906.018296] am65-cpsw-nuss 8000000.ethernet eth0: Link is Up - 1Gbps/Full - flow control rx/tx

root@am64xx-evm:~/xdp-tools/xdp-bench# ping 192.168.1.36
PING 192.168.1.36 (192.168.1.36) 56(84) bytes of data.
From 192.168.1.100 icmp_seq=1 Destination Host Unreachable
From 192.168.1.100 icmp_seq=2 Destination Host Unreachable
From 192.168.1.100 icmp_seq=3 Destination Host Unreachable
^C

--- 192.168.1.36 ping statistics ---
5 packets transmitted, 0 received, +3 errors, 100% packet loss, time 4079ms
pipe 4


---test log ends---

I will try to test with commit 8acacc40f733 ("net: ethernet: ti: am65-cpsw: Add minimal XDP support")
to see if it works there. If it does then I can do a bisect.

If you have better ideas please let me know. Thanks!

[1] https://lore.kernel.org/all/20240703-am65-cpsw-multi-rx-v3-0-f11cd860fd72@kernel.org/
[2] https://github.com/xdp-project/xdp-tools

> ---
> Changes in v9:
> - In k3_cppi_desc_pool_destroy(), free memory allocated for pool.
> - In k3_cppi_desc_pool_create_name() function, remove unnecessary
> error messages on mem alloc failures.
> - In k3_cppi_desc_pool_create_name() function, move desc_infos alloc
> forward to leverage pool_name freeing in gen_pool_destroy().
> - In k3_cppi_desc_pool_create_name() function, remove unnecessary
> 'ret = -ENOMEM' since ret is already initialized with -ENOMEM value.
> - For rx, do not build the skb upfront any more, Instead, give the page
> to the HW then build the skb once HW sends a completion.
> - Link to v8: https://lore.kernel.org/r/20240223-am65-cpsw-xdp-basic-v8-0-f3421b58da09@baylibre.com
> 
> Changes in v8:
> - Fix some warnings reported by patchwork.
> - Link to v7: https://lore.kernel.org/r/20240223-am65-cpsw-xdp-basic-v7-0-c3857c82dadb@baylibre.com
> 
> Changes in v7:
> - Move xdp_do_flush() function call in am65_cpsw_nuss_rx_poll().
> - Link to v6: https://lore.kernel.org/r/20240223-am65-cpsw-xdp-basic-v6-0-212eeff5bd5f@baylibre.com
> 
> Changes in v6:
> - In k3_cppi_*() functions, use const qualifier when the content of
> pool is not modified.
> - Add allow_direct bool parameter to am65_cpsw_alloc_skb() function
> for direct use by page_pool_put_full_page().
> - Link to v5: https://lore.kernel.org/r/20240223-am65-cpsw-xdp-basic-v5-0-bc1739170bc6@baylibre.com
> 
> Changes in v5:
> - In k3_cppi_desc_pool_destroy(), free memory allocated for desc_infos.
> - Link to v4: https://lore.kernel.org/r/20240223-am65-cpsw-xdp-basic-v4-0-2e45e5dec048@baylibre.com
> 
> Changes in v4:
> - Add skb_mark_for_recycle() in am65_cpsw_nuss_rx_packets() function.
> - Specify napi page pool parameter in am65_cpsw_create_xdp_rxqs() function.
> - Add benchmark numbers (with VS without page pool) in the commit description.
> - Add xdp_do_flush() in am65_cpsw_run_xdp() function for XDP_REDIRECT case.
> - Link to v3: https://lore.kernel.org/r/20240223-am65-cpsw-xdp-basic-v3-0-5d944a9d84a0@baylibre.com
> 
> Changes in v3:
> - Fix a potential issue with TX buffer type, which is now set for each buffer.
> - Link to v2: https://lore.kernel.org/r/20240223-am65-cpsw-xdp-basic-v2-0-01c6caacabb6@baylibre.com
> 
> Changes in v2:
> - Use page pool memory model instead of MEM_TYPE_PAGE_ORDER0.
> - In am65_cpsw_alloc_skb(), release reference on the page pool page
> in case of error returned by build_skb().
> - [nit] Cleanup am65_cpsw_nuss_common_open/stop() functions.
> - [nit] Arrange local variables in reverse xmas tree order.
> - Link to v1: https://lore.kernel.org/r/20240223-am65-cpsw-xdp-basic-v1-1-9f0b6cbda310@baylibre.com
> 
> ---
> Julien Panis (3):
>       net: ethernet: ti: Add accessors for struct k3_cppi_desc_pool members
>       net: ethernet: ti: Add desc_infos member to struct k3_cppi_desc_pool
>       net: ethernet: ti: am65-cpsw: Add minimal XDP support
> 
>  drivers/net/ethernet/ti/am65-cpsw-nuss.c    | 659 ++++++++++++++++++++++++----
>  drivers/net/ethernet/ti/am65-cpsw-nuss.h    |  13 +
>  drivers/net/ethernet/ti/k3-cppi-desc-pool.c |  46 +-
>  drivers/net/ethernet/ti/k3-cppi-desc-pool.h |   6 +
>  4 files changed, 623 insertions(+), 101 deletions(-)
> ---
> base-commit: 6613476e225e090cc9aad49be7fa504e290dd33d
> change-id: 20240223-am65-cpsw-xdp-basic-4db828508b48
> 
> Best regards,

-- 
cheers,
-roger