There are some useful tools in Unix/Linux to check out how the system is going on.

Here is a short summery of them:

This comes from a link below.

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Linux性能诊断工具

http://www.2cto.com/os/201409/330096.html

vmstat：虚拟内存状况 –swpd free buff cache si so in cs 参考：http://www.cnblogs.com/ggjucheng/archive/2012/01/05/2312625.html

iostat：io状况 avgqu-sz await svctm 参考：http://blog.csdn.net/dbanote/article/details/17784429 
mpstat: cpu状况 sys usr iowait 参考：http://blog.csdn.net/evils798/article/details/7524474 
ifstat：网络状况 –in out 
dstat：所有资源统计汇总 –资源汇总 参考：http://blog.csdn.net/yuandianlws/article/details/7004364 
tcpstat: 查看某个tcp端口的响应时间 tcprstat -lxxx.xxx.xxx.xxx -p 3306 -t 1 -n 0 
参考：http://my.oschina.net/moooofly/blog/157063 
tcpdump: 抓包 tcprstat -l xxx.xxx.xxx.xxx -p 3306 -t 1 -n 0

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Let's see another one specifically which is neat to use when analysing TCP capture details

Notice: tool 'tcprstat' is better to test the request/response timing durance and etc..

while tool 'tcpstat' has something to do with its package capturing.

'tcpdump' is another great tool which works with them.

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TCP capture analysis and TCP analogy

For tool 'tcprstat'

Here's its github page: https://github.com/Lowercases/tcprstat/

To install 'tcprstat' and 'tcpstat'

git clone https://github.com/Lowercases/tcprstat.git

cd tcprstat

chmod +x bootstrap

# if you are using debian/ubuntu/or ubuntu's derived destros, you would need to install package automake and autoconf

apt-get install automake autoconf -y

./bootstrap

#then

./configure --prefix=/usr/local # wherever the path you want

make

make install

# notice there are no package tcprstat in debian/ubuntu's software source repository. but they have the package 'tcpstat'. So,

apt-get install tcpstat -y

http://my.oschina.net/moooofly/blog/157063

But I have to clearify that there are some errors in the ariticle that the author tried to

state the differences or the similarities between the tool 'tcprstat' and the tool 'tcpstat'.

Actually his essay is all about the tool 'tcprstat'.

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How to figure out the TCP package in an interactive chart?

He uses PHP, tcpstat and gnuplot to decorate the statistics.

Here's is the HOW-TO:

http://www.frenchfries.net/paul/tcpstat/gnuplot_howto.html

And it's tutorial from youtube:

https://www.youtube.com/watch?v=fwmmRdT351Q