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Top command and options- Performance Measurement commands for Unix

Top command and options


What server side statistics should be gathered during performance testing. We have not yet looked in to specific statistics which we should gather for server side monitoring. In this post we would have a look at useful Linux commands which can be used to gather several important performance statistics. We would use these commands in future performance testing tutorials to gather server side performance statistics. Most of the description of these commands is from command manual. So lets begin -  

The top program provides a dynamic real-time view of a running system.  It can display system summary information as well as a list of processes or threads currently being managed by the Linux kernel.

Type the following command:

$ top
top.png

The top command used to display all the running and active real-time processes in ordered list and updates it regularly. Press ‘c‘ option in running top command, it will display absolute path of running process.
If you want to kill a running process then use kill command as - {kill -9 <process-id>}

Press (Shift+W) to save the running top command results under /root/.toprc.

OPTIONS

-u | -U  :User-filter-mode as:  -u | -U number or name
Display only processes with a user id or user name matching that given.  The '-u' option matches on  effective user whereas  the  '-U' option matches on any user (real, effective, saved, or filesystem).

Prepending  an  exclamation point ('!') to the user id or name instructs top to display only processes with users not matching the one provided.
$ top -u tarun
replace tarun with your username ;-)

top.png

-c  :Command-line/Program-name toggle Starts top with the last remembered 'c' state reversed. Thus, if top was displaying command lines, now that field will show program        names, and visa versa. See the 'c' interactive command for additional information. You can use this command to display absolute path of running process.
$ top -u tarun

top.png
-d  :Delay-time interval as: -d ss.t (secs.tenths) Specifies the delay between screen updates, and overrides the corresponding value in one's personal configuration file or the startup default.

$ top -d 1

No screen capture, try it yourself ;-)




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