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是否存在瓶颈？

因为报文从网卡到系统是经过PCIe总线来传输的，PCIe总线的吞吐将直接影响数据包从网卡拷贝到内存的速率。通过lspci -s 03:00.1 -vv | grep Lnk可以查看当前网卡的PCIe速率，其中03:00.1是网卡的PCIe地址，可通过lspci -v|grep Ethernet查到。

由上图可以看到网口能力是传输速率5GT/s，总线宽带x8（LnkCap），实际使用的是传输速率5GT/s，总线宽带x8（LnkSta），工作正常。如果传输速率和总线带宽下降，则需要调试PCIe兼容性问题。一般是服务器与网卡兼容性问题，可以更换网卡或者更换服务器。如果有条件，可以找服务器厂商从bios等方面进行详细定位解决兼容性问题。

2. rte_rx_queue中的数据包没有及时消费掉？

1. 检查CPU运行模式，cpupower frequency-info
   
   如果当前运行在powersave模式下，可以将其修改为performance，提升CPU频率，cpupower frequency-set -g performance。