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Oracle Tips by Burleson |
Top Memory and CPU users
You may recall an earlier discussion of the ps command for
determining process status. When we specify the u option with
the ps command, columns representing the percentage of CPU
and the percentage of memory that a process is using are
displayed as represented below by columns 3 and 4.
# ps u
USER PID %CPU %MEM VSZ RSS TTY STAT START
TIME COMMAND
terry 4968 0.0 0.5 5644 1320 pts/6 S 11:21
0:00 -bash
terry 5120 0.0 0.2 3440 756 pts/6 R 11:42
0:00 ps u
We can then add options to the ps command to include all
processes, not just our own (ax) and build a complex command
to display the top CPU consumer and the top memory user
tasks.
Display top CPU user
ps aux | sort -n +2 | tail -1
root 2201 0.2 3.2 36564 8464 ? S Oct17
2:18 /usr/X11R6/bin/X :0 -audit 0 -auth /var/gdm/:0.Xauth -
nolisten tcp vt7
Display top Memory user
$ ps aux | sort -n +3 | tail -1
gdm 3718 0.0 3.5 20744 9012 ? S 00:09
0:36 /usr/bin/gdmgreeter
We will discuss more about building complex commands in the
shell scripting chapter. For now, accept that commands can
redirect their output to other commands to perform a series of
operations. In the example above displaying the top memory
user we display all processes, then sort the processes in
ascending sequence using the numeric value found in column 4
(+3), then display the last value (highest) in the sorted list.
If we wanted to see the top 5 (high to low) memory users in the
system we could modify our command string as follows:
ps aux|sort -nr +3|grep -v
USER|head -5
gdm 3718 0.0 3.5 20744 9012 ? S 00:09
0:37 /usr/bin/gdmgreeter
root 2201 0.2 3.2 36564 8464 ? S Oct17
2:19 /usr/X11R6/bin/X :0 -audit 0 -auth /var/gdm/:0.Xauth -
nolisten tcp vt7
xfs 1887 0.0 1.2 4996 3152 ? S Oct17
0:00 xfs -droppriv -daemon
root 2190 0.0 1.1 12664 2972 ? S Oct17
0:03 /usr/bin/gdm-binary -nodaemon
terry 3286 0.0 1.0 8296 2776 ? S Oct17
0:00 /usr/libexec/bonobo-activation-server --ac-activate --
ior-output-fd=18
The above book excerpt is from:
Easy Linux
Commands
Working Examples of Linux Command Syntax
ISBN:
0-9759135-0-6
Terry Clark
http://www.rampant-books.com/book_2005_1_linux_commands.htm |
