top(1)

NAME

top — display and update information about the top processes on the system

SYNOPSIS

top [-s time] [-d count] [-q] [-u] [-h] [-n number]

DESCRIPTION

top displays the top processes on the system and periodically updates the information. Raw CPU percentage is used to rank the processes.

Options

top recognizes the following command-line options:

-s time: Set the delay between screen updates to time seconds. The default delay between updates is 5 seconds.
-d count: Show only count displays, then exit. A display is considered to be one update of the screen. This option is used to select the number of displays to be shown before the program exits.
-q: This option runs the top program at the same priority as if it is executed via a nice -20 command so that it will execute faster (see nice(1)). This can be very useful in discovering any system problem when the system is very sluggish. This option is accessibly only to users who have appropriate privileges.
-u: User ID (uid) numbers are displayed instead of usernames. This improves execution speed by eliminating the additional time required to map uid numbers to user names.
-h: Hides the individual CPU state information for systems having multiple processors. Only the average CPU status will be displayed.
-n number: Show only number processes per screen. Note that this option is ignored if number is greater than the maximum number of processes that can be displayed per screen.

Screen-Control Commands

When displaying multiple-screen data, top recognizes the following keyboard screen-control commands:

j: Display next screen if the current screen is not the last screen.
k: Display previous screen if the current screen is not the first screen.
t: Display the first (top) screen.

Program Termination

To exit the program and resume normal user activities, type q at any time.

Display Description

Three general classes of information are displayed by top:

System Data:

The first few lines at the top of the display show general information about the state of the system, including:

System name and current time.
Load averages in the last one, five, and fifteen minutes.
Number of existing processes and the number of processes in each state (sleeping, waiting, running, starting, zombie, and stopped).
Percentage of time spent in each of the processor states (user, nice, system, idle, interrupt and swapper) per processor on the system.
Average value for each of the processor states (only on multi-processor systems).

Memory Data

Includes virtual and real memory in use (with the amount of memory considered "active" in parentheses) and the amount of free memory.

Process Data

Information about individual processes on the system. When process data cannot fit on a single screen, top divides the data into two or more screens. To view multiple-screen data, use the j, k, and t commands described previously. Note that the system- and memory-data displays are present in each screen of multiple-screen process data.

Process data is displayed in a format similar to that used by ps(1):

CPU: Processor number on which the process is executing (only on multi-processor systems).
TTY: Terminal interface used by the process.
PID: Process ID number.
USERNAME: Name of the owner of the process. When the -u option is specified, the user ID (uid) is displayed instead of USERNAME.
PRI: Current priority of the process.
NI: Nice value ranging from -20 to +20.
SIZE: Total size of the process in kilobytes. This includes text, data, and stack.
RES: Resident size of the process in kilobytes. The resident size information is, at best, an approximate value.
STATE: Current state of the process. The various states are sleep, wait, run, idl, zomb, or stop.
TIME: Number of system and CPU seconds the process has consumed.
%WCPU: Weighted CPU (central processing unit) percentage.
%CPU: Raw CPU percentage. This field is used to sort the top processes.
COMMAND: Name of the command the process is currently running.

EXAMPLES

top can be executed with or without command-line options. To display five screens of data at two-second intervals then automatically exit, use:

top -s2 -d5 

AUTHOR

top was developed by HP and William LeFebvre of Rice University.