On Mon, 2021-01-04 at 18:59 +0800, Xuan Zhuo wrote: > hi > > In the process of developing xdp socket, we tried to directly use > page to > construct skb directly, to avoid data copy. And the MAC information > is also in > the page, which caused the linear space of skb to be empty. In this > case, I > encountered a problem : > > mlx5_core 0000:3b:00.1 eth1: Error cqe on cqn 0x817, ci 0x8, qn > 0x1dbb, opcode 0xd, syndrome 0x1, vendor syndrome 0x68 > 00000000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 > 00000010: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 > 00000020: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 > 00000030: 00 00 00 00 60 10 68 01 0a 00 1d bb 00 0f 9f d2 > WQE DUMP: WQ size 1024 WQ cur size 0, WQE index 0xf, len: 64 > 00000000: 00 00 0f 0a 00 1d bb 03 00 00 00 08 00 00 00 00 > 00000010: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 > 00000020: 00 00 00 2b 00 08 00 00 00 00 00 05 9e e3 08 00 > 00000030: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 > mlx5_core 0000:3b:00.1 eth1: ERR CQE on SQ: 0x1dbb > > > And when I try to copy only the mac address into the linear space of > skb, the > other parts are still placed in the page. When constructing skb in > this way, I > found that although the data can be sent successfully, the sending > performance > is relatively poor!! >
Hi, This is an expected behavior of ConnectX4-LX, ConnectX4-LX requires the driver to copy at least the L2 headers into the linear part, in some DCB/DSCP configuration it will require L3 headers. to check what the current configuration, you can check from the driver code: mlx5e_calc_min_inline() // Calculates the minimum required headers to copy to linear part per packet and sq->min_inline_mode; stores the minimum required by the FW. This "must copy" requirement doesn't exist for ConnectX5 and above .. > I would like to ask, is there any way to solve this problem? > > dev info: > driver: mlx5_core > version: 5.10.0+ > firmware-version: 14.21.2328 (MT_2470112034) > expansion-rom-version: > bus-info: 0000:3b:00.0 > supports-statistics: yes > supports-test: yes > supports-eeprom-access: no > supports-register-dump: no > supports-priv-flags: yes > > > >
