昨晚浏览器页面突然慢得无法忍受, ifconfig 一看, 网卡上 RX dropped 数值很大,而且不断在增大
网上可以找到不少如下的讨论:
Beginning with kernel 2.6.37, it has been changed the meaning of dropped packet count. Before, dropped packets was most likely due to an error. Now, the rx_dropped counter shows statistics for dropped frames because of:
Softnet backlog full
Bad / Unintended VLAN tags
Unknown / Unregistered protocols
IPv6 frames when the server is not configured for IPv6
If any frames meet those conditions, they are dropped before the protocol stack and the rx_dropped counter is incremented.
Care should be taken to confirm that frames are not being legitimately dropped. A quick way to test this (WARNING: this test does not work for bonding interfaces) is to start a packet capture:
host:~# tcpdump
And then watching the rx_dropped counter. If it stops incrementing while the tcpdump is running; then it is more than likely showing drops because of the reasons listed earlier. If frames continue to be dropped while running tcpdump, investigation should take place to determine root cause.
The tcpdump change interface setting, such as promiscuous mode. In promiscuous mode, some checks are disabled.
然后我试了运行 tcpdump, 在多次执行 ifconfig, RX dropped 数字还是不断在增大.
我通过系统监视器和Top命令看到的CPU和 内存都占用不高
网上还有说 netstat -s 可以继续查原因的, 我看了一下netstat -s 返回的结果, 不知道该关心哪个指标.
这会儿浏览器页面刷新又不卡了,但RX dropped 数字还是不停地上涨. 也就是说我甚至无法确定 这个数字 和 浏览体验之间的关系.
