cpupower frequency-info

 

 

[root@localhost ixgbe]# cpupower frequency-info
analyzing CPU 0:
  driver: cppc_cpufreq
  CPUs which run at the same hardware frequency: 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
  CPUs which need to have their frequency coordinated by software: 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
  maximum transition latency: 40.0 us
  hardware limits: 200 MHz - 2.60 GHz
  available cpufreq governors: conservative ondemand userspace powersave performance
  current policy: frequency should be within 1000 MHz and 2.60 GHz.
                  The governor "performance" may decide which speed to use
                  within this range.
  current CPU frequency: Unable to call hardware
  current CPU frequency: 2.60 GHz (asserted by call to kernel)
[root@localhost ixgbe]# 

 

[root@localhost ixgbe]# lspci -s 05:00.0 -vv | grep Lnk
                LnkCap: Port #0, Speed 8GT/s, Width x16, ASPM not supported, Exit Latency L0s unlimited, L1 unlimited
                LnkCtl: ASPM Disabled; RCB 128 bytes Disabled- CommClk-
                LnkSta: Speed 8GT/s, Width x16, TrErr- Train- SlotClk- DLActive- BWMgmt- ABWMgmt-
                LnkCtl2: Target Link Speed: 8GT/s, EnterCompliance- SpeedDis-
                LnkSta2: Current De-emphasis Level: -3.5dB, EqualizationComplete+, EqualizationPhase1+
[root@localhost ixgbe]#

1. PCIe是否存在瓶頸？

因為報文從網卡到系統是經過PCIe總線來傳輸的，PCIe總線的吞吐將直接影響數據包從網卡拷貝到內存的速率。通過lspci -s 03:00.1 -vv | grep Lnk可以查看當前網卡的PCIe速率，其中03:00.1是網卡的PCIe地址，可通過lspci -v|grep Ethernet查到。

由上圖可以看到網口能力是傳輸速率5GT/s，總線寬帶x8（LnkCap），實際使用的是傳輸速率5GT/s，總線寬帶x8（LnkSta），工作正常。如果傳輸速率和總線帶寬下降，則需要調試PCIe兼容性問題。一般是服務器與網卡兼容性問題，可以更換網卡或者更換服務器。如果有條件，可以找服務器廠商從bios等方面進行詳細定位解決兼容性問題。

2. rte_rx_queue中的數據包沒有及時消費掉？

1. 檢查CPU運行模式，cpupower frequency-info
   
   如果當前運行在powersave模式下，可以將其修改為performance，提升CPU頻率，cpupower frequency-set -g performance。