在前面用newlisp监控进程的时候，其实只是判断进程是否存活，如果不是，则重新启动。现在还要实现另一个功能，监控进程的cpu和memory占用情况。
如果用man ps查看ps命令，你会看到下面的参数：
CODE HEADER DESCRIPTION
%cpu %CPU cpu utilization of the process in "##.#" format. Currently, it is the CPU time used divided by the time the process
has been running (cputime/realtime ratio), expressed as a percentage. It will not add up to 100% unless you are
lucky. (alias pcpu).
%mem %MEM ratio of the process‘s resident set size to the physical memory on the machine, expressed as a percentage.
(alias pmem).
args COMMAND command with all its arguments as a string. Modifications to the arguments may be shown. The output in this column
may contain spaces. A process marked <defunct> is partly dead, waiting to be fully destroyed by its parent.
Sometimes the process args will be unavailable; when this happens, ps will instead print the executable name in
brackets. (alias cmd, command). See also the comm format keyword, the -f option, and the c option.
When specified last, this column will extend to the edge of the display. If ps can not determine display width, as
when output is redirected (piped) into a file or another command, the output width is undefined (it may be 80,
unlimited, determined by the TERM variable, and so on). The COLUMNS environment variable or --cols option may be
used to exactly determine the width in this case. The w or -w option may be also be used to adjust width.
blocked BLOCKED mask of the blocked signals, see signal(7). According to the width of the field, a 32 or 64-bit mask in hexadecimal
format is displayed. (alias sig_block, sigmask).
....
%cpu 和 %mem就是我需要的。
通过下面的命令可以监控一个进程的cpu和memory使用情况：
ps -p <pid> -o %cpu,%mem,cmd
pid哪里来，通过pidof命令。现在用newlisp将这两个命令连接在一起：
#!/usr/bin/newlisp (set ‘pid (exec "pidof data_service_d")) (set ‘cmd (string "ps -p " (first pid) " -o %cpu,%mem,cmd")) (println (exec cmd)) (exit)
执行一下：
root@jstc:/opt/detector# ./process_status.lsp
("%CPU %MEM CMD" " 0.2 0.3 ./data_service_d ./config.xml")
效果不错。以后再加点代码发到我的风洞服务器上，就可以在网站上绘制折线图了。
关于top和ps反映出来的cpu占用率不一样，是个问题：
参考下面的帖子：
http://superuser.com/questions/643331/ps-and-top-give-different-cpu-usage
该帖提出用shift + I来通知top监控站全部cpu核的使用率，而不是单核。
http://unix.stackexchange.com/questions/58539/top-and-ps-not-showing-the-same-cpu-result
该贴答案指出ps不是最准确的cpu利用率跟踪工具，而应该使用top -p $pid的方式
因此ps的方法只能是一个不准确的用法。