具体的可以参考这里
他的最大特点是快, 当你的系统有上万个tcp链接要了解的时候的时候, 你就知道我说什么了. netstat等常规工具变成废铁了, 这时候他的作用就非常明显了.
/proc interface is inadequate, unfortunately. When amount of sockets is enough large, netstat or even plain cat /proc/net/tcp/ cause nothing but pains and curses. In linux-2.4 the desease became worse: even if amount of sockets is small reading /proc/net/tcp/ is slow enough.
This utility presents a new approach, which is supposed to scale well. I am not going to describe technical details here and will concentrate on description of the command. The only important thing to say is that it is not so bad idea to load module tcp_diag, which can be found in directory Modules of iproute2. If you do not make this ss will work, but it falls back to /proc and becomes slow like netstat, well, a bit faster yet (see section “Some numbers”).
从技术上讲, 它主要是通过/proc来获取各种各样的统计信息. 特别是当处理tcp的时候用到了, tcp_diag功能. tcp_diag是tcp协议栈用于诊断和统计的一个模块, 用netfilter来获取第一手的信息的. ss就用到了这个技术, 保证了信息的快捷获取.
这个软件是隶属于iproute包的, 如果你的系统没有的话可以这样安装:
apt-get -y install iproute
|
用它可以了解下协议栈占用的内存, 每个链接的队列使用情况, 每个链接属于哪个进程.
而之前唯一能用的就是:
watch -n 1 'cat /proc/net/sockstat'
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下面简单介绍下他的使用:
root@ubuntu:/usr/src/iproute-20090324/misc# ss --help
|
ss [ OPTIONS ] [ FILTER ] |
-V, --version output version information |
-n, --numeric don't resolve service names |
-r, --resolve resolve host names |
-a, --all display all sockets |
-l, --listening display listening sockets |
-o, --options show timer information |
-e, --extended show detailed socket information |
-m, --memory show socket memory usage |
-p, --processes show process using socket |
-i, --info show internal TCP information |
-s, --summary show socket usage summary |
-4, --ipv4 display only IP version 4 sockets |
-6, --ipv6 display only IP version 6 sockets |
-0, --packet display PACKET sockets |
-t, --tcp display only TCP sockets |
-u, --udp display only UDP sockets |
-d, --dccp display only DCCP sockets |
-w, --raw display only RAW sockets |
-x, --unix display only Unix domain sockets |
-f, --family=FAMILY display sockets of type FAMILY
|
QUERY := {all|inet|tcp|udp|raw|unix|packet|netlink}[,QUERY] |
-F, --filter=FILE read filter information from FILE
|
FILTER := [ state TCP-STATE ] [ EXPRESSION ] |
root@ubuntu:/usr/src/iproute-20090324/misc# ss -s
|
TCP: 21 (estab 7, closed 0, orphaned 0, synrecv 0, timewait 0/0), ports 0 |
root@ubuntu:/usr/src/iproute-20090324/misc# ss -t -m
|
State
Recv-Q
Send-Q
Local
Address:Port
Peer Address:Port |
ESTAB 0 0 192.168.235.147:ssh 192.168.235.155:4251
|
CLOSE-WAIT
38
0
192.168.235.147:13910
174.36.30.67:https |
ESTAB 0 0 192.168.235.147:ssh 192.168.235.155:4635
|
ESTAB
0
0
127.0.0.1:4369
127.0.0.1:54620 |
ESTAB 0 0 192.168.235.147:ssh 192.168.235.155:1095
|
ESTAB
0
0
127.0.0.1:4369
127.0.0.1:44234 |
ESTAB
0
0
127.0.0.1:54620
127.0.0.1:4369 |
ESTAB
0
0
127.0.0.1:44234
127.0.0.1:4369 |
root@ubuntu:/usr/src/iproute-20090324/misc# ss -p
|
State
Recv-Q
Send-Q
Local
Address:Port
Peer Address:Port |
ESTAB 0 0 192.168.235.147:ssh 192.168.235.155:4251 users:(("sshd",8373,3))
|
CLOSE-WAIT
38
0
192.168.235.147:13910
174.36.30.67:https users:(("dropbox",2674,13))
|
ESTAB 0 0 192.168.235.147:ssh 192.168.235.155:4635 users:(("sshd",350,3))
|
ESTAB
0
0
127.0.0.1:4369
127.0.0.1:54620 users:(("epmd",28338,5))
|
ESTAB 0 0 192.168.235.147:ssh 192.168.235.155:1095 users:(("sshd",29044,3))
|
ESTAB
0
0
127.0.0.1:4369
127.0.0.1:44234 users:(("epmd",28338,4))
|
ESTAB
0
0
127.0.0.1:54620
127.0.0.1:4369 users:(("beam.smp",25947,11))
|
ESTAB
0
0
127.0.0.1:44234
127.0.0.1:4369 users:(("inet_gethost",23783,8),("inet_gethost",23784,8))
|
root@ubuntu:/usr/src/iproute-20090324/misc# ss -i
|
State
Recv-Q
Send-Q
Local
Address:Port
Peer Address:Port |
ESTAB 0 0 192.168.235.147:ssh 192.168.235.155:4251
|
cubic rto:396 rtt:124.5/66 ato:40 cwnd:4 send 375.3Kbps rcv_rtt:296456 rcv_space:66472 |
CLOSE-WAIT
38
0
192.168.235.147:13910
174.36.30.67:https |
cubic wscale:7,9 rto:612 rtt:256/52 ato:40 cwnd:5 send 213.8Kbps rcv_rtt:259 rcv_space:5840 |
ESTAB 0 0 192.168.235.147:ssh 192.168.235.155:4635
|
cubic rto:356 rtt:144/33 ato:40 cwnd:4 send 324.4Kbps rcv_rtt:511258 rcv_space:46760 |
ESTAB
0
0
127.0.0.1:4369
127.0.0.1:54620 |
cubic wscale:9,9 rto:204 rtt:4/2 ato:40 cwnd:3 send 98.3Mbps rcv_space:32768 |
ESTAB 0 0 192.168.235.147:ssh 192.168.235.155:1095
|
cubic rto:232 rtt:21/18 ato:40 cwnd:5 ssthresh:4 send 2.8Mbps rcv_rtt:173516 rcv_space:118904 |
ESTAB
0
0
127.0.0.1:4369
127.0.0.1:44234 |
cubic wscale:9,9 rto:204 rtt:4/2 ato:40 cwnd:3 send 98.3Mbps rcv_space:32768 |
ESTAB
0
0
127.0.0.1:54620
127.0.0.1:4369 |
cubic wscale:9,9 rto:204 rtt:4/2 ato:40 cwnd:3 send 98.3Mbps rcv_space:32792 |
ESTAB
0
0
127.0.0.1:44234
127.0.0.1:4369 |
cubic wscale:9,9 rto:204 rtt:4/2 ato:40 cwnd:3 send 98.3Mbps rcv_space:32792 |
root@ubuntu:/usr/src/iproute-20090324/misc# ss -e
|
State
Recv-Q
Send-Q
Local
Address:Port
Peer Address:Port |
ESTAB 0 0 192.168.235.147:ssh 192.168.235.155:4251 timer:(keepalive,50min,0) ino:1843366 sk:c2ea2600
|
CLOSE-WAIT
38
0
192.168.235.147:13910
174.36.30.67:https ino:12200 sk:c2ea2140 |
ESTAB 0 0 192.168.235.147:ssh 192.168.235.155:4635 timer:(keepalive,2min59sec,0) ino:1101514 sk:c2ea4740
|
ESTAB
0
0
127.0.0.1:4369
127.0.0.1:54620 ino:2309430 sk:c2ea2ac0 |
ESTAB 0 0 192.168.235.147:ssh 192.168.235.155:1095 timer:(keepalive,6min59sec,0) ino:379842 sk:c2f4af80
|
ESTAB
0
0
127.0.0.1:4369
127.0.0.1:44234 ino:2044745 sk:c2ea3440 |
ESTAB
0
0
127.0.0.1:54620
127.0.0.1:4369 ino:2309429 sk:c2ea7200 |
ESTAB
0
0
127.0.0.1:44234
127.0.0.1:4369 ino:2044744 sk:c2ea1300 |
root@ubuntu:/usr/src/iproute-20090324/misc# ss -o
|
State
Recv-Q
Send-Q
Local
Address:Port
Peer Address:Port |
ESTAB 0 0 192.168.235.147:ssh 192.168.235.155:4251 timer:(keepalive,50min,0)
|
CLOSE-WAIT
38
0
192.168.235.147:13910
174.36.30.67:https |
ESTAB 0 0 192.168.235.147:ssh 192.168.235.155:4635 timer:(keepalive,2min50sec,0)
|
ESTAB
0
0
127.0.0.1:4369
127.0.0.1:54620 |
ESTAB 0 0 192.168.235.147:ssh 192.168.235.155:1095 timer:(keepalive,6min50sec,0)
|
ESTAB
0
0
127.0.0.1:4369
127.0.0.1:44234 |
ESTAB
0
0
127.0.0.1:54620
127.0.0.1:4369 |
ESTAB
0
0
127.0.0.1:44234
127.0.0.1:4369 |
Have fun!!!
