Hi, Could you try to change interval configuration to check if it helps? Please refer to i40e_calc_itr_interval function. In theory, the lower interval, the lower latency.
BR, Beilei > -----Original Message----- > From: jiangheng <[email protected]> > Sent: Wednesday, July 5, 2023 9:33 AM > To: Zhang, Yuying <[email protected]>; Xing, Beilei > <[email protected]> > Cc: [email protected] > Subject: the packet delay is too long when I used dpdk i40e NIC sent single > packet > > Hi Beilei: > we used dpdk implement a user mode tcp protocol stack, and we are testing > the delay of a single packet. > however, on i40e NIC(XL710), the packet delay is higher than that of the > kernel. > After some tests, we find that the time consuming may be the pahse when i40e > sends packet.(period from rte_eth_tx_burst to packet be sent) The same test is > performed on the ixgbe(82599) NIC. the delay is lower than that in kernel. > > I used dpdk-21.11 stable version. > I tried upgrading the i40e's firmware version to 9.10, but there was no > improvement. > Any suggestion? > Thank you. > > > > The following is packet delay statistics of tcpdump: > i40e NIC: > 410 10.373817 192.168.4.4 192.168.4.5 TCP 64 8877 > →58312 [ACK] Seq=6511 Ack=9642 Win=1048384 Len=0 > 10us > 411 10.373827 192.168.4.4 192.168.4.5 TCP 94 58312 > →8877 [PSH, ACK] Seq=9642 Ack=6511 Win=1048512 Len=36 > 27us > 412 10.373854 192.168.4.5 192.168.4.4 TCP 60 8877 > →58312 [ACK] Seq=6511 Ack=9678 Win=1048320 Len=0 > 9us > 413 10.373863 192.168.4.5 192.168.4.4 TCP 90 58312 > →8877 [PSH, ACK] Seq=9642 Ack=6511 Win=1048512 Len=36 > 28us > 414 10.373891 192.168.4.4 192.168.4.5 TCP 64 8877 > →58312 [ACK] Seq=6511 Ack=9678 Win=1048320 Len=0 > 11us > 415 10.373902 192.168.4.4 192.168.4.5 TCP 94 58312 > →8877 [PSH, ACK] Seq=9678 Ack=6511 Win=1048512 Len=36 > 28us > 416 10.373930 192.168.4.5 192.168.4.4 TCP 60 8877 > →58312 [ACK] Seq=6511 Ack=9714 Win=1048320 Len=0 > 11us > 417 10.373941 192.168.4.5 192.168.4.4 TCP 90 58312 > →8877 [PSH, ACK] Seq=9678 Ack=6511 Win=1048512 Len=36 > 25us > 418 10.373967 192.168.4.4 192.168.4.5 TCP 64 8877 > →58312 [ACK] Seq=6511 Ack=9714 Win=1048320 Len=0 > 11us > 419 10.373978 192.168.4.4 192.168.4.5 TCP 94 58312 > →8877 [PSH, ACK] Seq=9714 Ack=6511 Win=1048512 Len=36 > 4us > 420 10.373982 192.168.4.5 192.168.4.4 TCP 60 8877 > →58312 [ACK] Seq=6511 Ack=9750 Win=1048256 Len=0 > > > ixgbe NIC: > 110 13.235208 192.168.4.12 192.168.4.11 TCP 64 8877 > →58312 [ACK] Seq=6511 Ack=7266 Win=1047808 Len=0 > 10us > 111 13.235218 192.168.4.12 192.168.4.11 TCP 94 58312 > →8877 [PSH, ACK] Seq=7266 Ack=6511 Win=1048512 Len=36 > 6us > 112 13.235224 192.168.4.11 192.168.4.12 TCP 64 8877 > →58312 [ACK] Seq=6511 Ack=7302 Win=1047744 Len=0 > 10us > 113 13.235234 192.168.4.11 192.168.4.12 TCP 94 58312 > →8877 [PSH, ACK] Seq=7266 Ack=6511 Win=1048512 Len=36 > 6us > 114 13.235240 192.168.4.12 192.168.4.11 TCP 64 8877 > →58312 [ACK] Seq=6511 Ack=7302 Win=1047744 Len=0 > 11us > 115 13.235251 192.168.4.12 192.168.4.11 TCP 94 58312 > →8877 [PSH, ACK] Seq=7302 Ack=6511 Win=1048512 Len=36 > 5us > 116 13.235256 192.168.4.11 192.168.4.12 TCP 64 8877 > →58312 [ACK] Seq=6511 Ack=7338 Win=1047744 Len=0 > 11us > 117 13.235267 192.168.4.11 192.168.4.12 TCP 94 58312 > →8877 [PSH, ACK] Seq=7302 Ack=6511 Win=1048512 Len=36 > 6us > 118 13.235273 192.168.4.12 192.168.4.11 TCP 64 8877 > →58312 [ACK] Seq=6511 Ack=7338 Win=1047744 Len=0 > 10us > 119 13.235283 192.168.4.12 192.168.4.11 TCP 94 58312 > →8877 [PSH, ACK] Seq=7338 Ack=6511 Win=1048512 Len=36 > 6us > 120 13.235289 192.168.4.11 192.168.4.12 TCP 64 8877 > →58312 [ACK] Seq=6511 Ack=7374 Win=1047680 Len=0
