Hi, I changed I40E_QUEUE_ITR_INTERVAL_DEFAULT to 10us, latency is significantly lower. what is the effect of modifying this parameter?
> 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 <jianghen...@huawei.com> >> Sent: Wednesday, July 5, 2023 9:33 AM >> To: Zhang, Yuying <yuying.zh...@intel.com>; Xing, Beilei >> <beilei.x...@intel.com> >> Cc: users@dpdk.org >> 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
