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Oracle Tips by Burleson |
Interactive Statistics Using
the TOP Utility
The top program provides a dynamic real-time view of a
running Linux system. It displays system summary information
as well as a list of processes currently being managed by the
operating system. The user has control over the types of system
summary information shown and the types, order and size of
information displayed for tasks.
The top utility can uncover utilization issues
Configuration changes to the information displayed can be
saved across restarts. See the manual page for top (man top) to
reference customization options because customization of the
top display is beyond the scope of this book.
In its default configuration, the top utility is used to show CPU
consumption, memory consumption, and the top sessions on a
Linux server. The default output from top is comprised of
several distinct reporting sections.
o Summary Area - Consisting of global server
information including the current number of users,
total tasks and their status (running, sleeping,
stopped, zombie), as well as CPU, memory, and
swap statistics.
o Message/Prompt Line - The command line just
above the column headers for entering top
commands interactively.
o Column Headers - A line usually displayed in
reverse video that defines the information displayed
in the task area.
o Process/Task Area - A display of the top running
tasks sorted by any of the displayed column values
(default is %mem descending).
$ top
top - 23:47:16 up 1 day, 1:41, 3 users, load average:
0.00, 0.00, 0.00
Tasks: 58 total, 1 running, 57 sleeping, 0 stopped,
0 zombie
Cpu(s): 0.5% us, 0.3% sy, 0.1% ni, 98.9% id, 0.2% wa,
0.0% hi, 0.0% si
Mem: 257124k total, 197480k used, 59644k free,
97640k buffers
Swap: 524152k total, 0k used, 524152k free,
25092k cached
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+
COMMAND
3718 gdm 15 0 20744 9012 17m S 1.9 3.5 1:21.54 gdmgreeter
6217 root 15 0 3236 844 1620 R 1.9 0.3 0:00.03 top
1 root 16 0 1612 464 1316 S 0.0 0.2 0:05.94 init
2 root 34 19 0 0 0 S 0.0 0.0 0:00.00 ksoftirqd/0
3 root 5 -10 0 0 0 S 0.0 0.0 0:00.00 events/0
4 root 5 -10 0 0 0 S 0.0 0.0 0:00.00 kblockd/0
7 root 5 -10 0 0 0 S 0.0 0.0 0:00.01 khelper
5 root 15 0 0 0 0 S 0.0 0.0 0:00.00 khubd
6 root 15 0 0 0 0 S 0.0 0.0 0:00.00 kapmd
8 root 15 0 0 0 0 S 0.0 0.0 0:00.71 pdflush
9 root 15 0 0 0 0 S 0.0 0.0 0:00.04 pdflush
11 root 15 -10 0 0 0 S 0.0 0.0 0:00.00 aio/0
10 root 15 0 0 0 0 S 0.0 0.0 0:00.31 kswapd0
123 root 16 0 0 0 0 S 0.0 0.0 0:00.00 kseriod
162 root 15 0 0 0 0 S 0.0 0.0 0:00.23 kjournald
1006 root 15 0 0 0 0 S 0.0 0.0 0:00.00 kjournald
1416 root 16 0 2724 620 1296 S 0.0 0.2 0:00.12 syslogd
1420 root 16 0 3208 440 1244 S 0.0 0.2 0:00.02 klogd
1983 root 19 0 2956 352 1232 S 0.0 0.1 0:00.00 mingetty
1989 root 20 0 1820 352 1232 S 0.0 0.1 0:00.00 mingetty
1995 root 18 0 2620 424 1232 S 0.0 0.2 0:00.00 mingetty
2001 root 20 0 3084 352 1232 S 0.0 0.1 0:00.00 mingetty
2002 root 15 0 12008 2208 10m S 0.0 0.9 0:00.14 gdm-binary
2190 root 15 0 12664 2972 10m S 0.0 1.2 0:03.02 gdm-binary
2201 root 15 0 36564 8464 28m S 0.0 3.3 2:51.99 X
2630 root 34 19 8976 2116 5936 S 0.0 0.8 0:00.92 cupsd
The first line of the top display lists a series of three numbers
prefixed by the words load average. The three values represent
the load averages for the past minute, the past 5 minutes, and
the past 15 minutes respectfully. Low load average values are
ideal, and values that exceed 1 indicate a potential bottleneck.
Whenever the value exceeds 1 there could potentially be a
processor overload problem.
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 |
