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TOP(1)									TOP(1)

NAME    [Toc]    [Back]

     top - display and update information about	the top	cpu processes

SYNOPSIS    [Toc]    [Back]

     top [ -SbiInqTu ] [ -dcount ] [ -stime ] [	-ofield	] [ -Uusername ] [
     number ]

DESCRIPTION    [Toc]    [Back]

     Top displays the top processes on the system and periodically updates
     this information.	If standard output is an intelligent terminal (see
     below) then as many processes as will fit on the terminal screen are
     displayed by default.  Otherwise, a good number of	them are shown (around
     20).  Raw cpu percentage is used to rank the processes.  If number	is
     given, then the top number	processes will be displayed instead of the

     Top makes a distinction between terminals that support advanced
     capabilities and those that do not.  This distinction affects the choice
     of	defaults for certain options.  In the remainder	of this	document, an
     "intelligent" terminal is one that	supports cursor	addressing, clear
     screen, and clear to end of line.	Conversely, a "dumb" terminal is one
     that does not support such	features.  If the output of top	is redirected
     to	a file,	it acts	as if it were being run	on a dumb terminal.

OPTIONS    [Toc]    [Back]

     -S	  Show system processes	in the display.	 The definition	of system
	  processes is system dependent	(See below).

     -b	  Use "batch" mode.  In	this mode, all input from the terminal is
	  ignored.  Interrupt characters (such as ^C and ^\) still have	an
	  effect.  This	is the default on a dumb terminal, or when the output
	  is not a terminal.

     -i	  Use "interactive" mode.  In this mode, any input is immediately read
	  for processing.  See the section on "Interactive Mode" for an
	  explanation of which keys perform what functions.  After the command
	  is processed,	the screen will	immediately be updated,	even if	the
	  command was not understood.  This mode is the	default	when standard
	  output is an intelligent terminal.

     -I	  Do (or do not) display idle processes	(toggle).  By default, top
	  displays only	active (ready to run or	running	on a processor)

     -n	  Use "non-interactive"	mode.  This is identical to "batch" mode.

     -q	  Renice top to	-20 so that it will run	faster.	 This can be used when
	  the system is	being very sluggish to improve the possibility of
	  discovering the problem.  This option	can only be used by root.

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TOP(1)									TOP(1)

     -T	  List data for	individual kernel threads.  Normally the information
	  presented is a summation across all threads of the process.  This is
	  of use when examining	POSIX threaded processes.

     -u	  Do not take the time to map uid numbers to usernames.	 Normally, top
	  will read as much of the file	"/etc/passwd" as is necessary to map
	  all the user id numbers it encounters	into login names.  This	option
	  disables all that, while possibly decreasing execution time.	The
	  uid numbers are displayed instead of the names.

	  Show only count displays, then exit.	A display is considered	to be
	  one update of	the screen.  This option allows	the user to select the
	  number of displays he	wants to see before top	automatically exits.
	  For intelligent terminals, no	upper limit is set.  The default is 1
	  for "batch" mode and dumb terminals.

	  Set the delay	between	screen updates to time seconds.	 The default
	  delay	between	updates	is 4 seconds.

	  Sort the process display area	on the specified field.	 The field
	  name is the name of the column as seen in the	output,	but in lower
	  case.	 Likely	values are "cpu", "size", "res", and "time", but may
	  vary on different operating systems.	Note that not all operating
	  systems support this option.

	  Show only those processes owned by username.	This option currently
	  only accepts usernames and will not understand uid numbers.

     Both count	and number fields can be specified as "infinite", indicating
     that they can stretch as far as possible.	This is	accomplished by	using
     any proper	prefix of the keywords "infinity", "maximum", or "all".	 The
     default for count on an intelligent terminal is, in fact, infinity.

     The environment variable TOP is examined for options before the command
     line is scanned.  This enables a user to set his or her own defaults.
     The number	of processes to	display	can also be specified in the
     environment variable TOP.	The options -I,	-S, and	-u are actually
     toggles.  A second	specification of any of	these options will negate the
     first.  Thus a user who has the environment variable TOP set to "-I" may
     use the command "top -I" to see only active processes.

INTERACTIVE MODE    [Toc]    [Back]

     When top is running in "interactive mode",	it reads commands from the
     terminal and acts upon them accordingly.  In this mode, the terminal is
     put in "CBREAK", so that a	character will be processed as soon as it is
     typed.  Almost always, a key will be pressed when top is between
     displays; that is,	while it is waiting for	time seconds to	elapse.	 If
     this is the case, the command will	be processed and the display will be

									Page 2

TOP(1)									TOP(1)

     updated immediately thereafter (reflecting	any changes that the command
     may have specified).  This	happens	even if	the command was	incorrect.  If
     a key is pressed while top	is in the middle of updating the display, it
     will finish the update and	then process the command.  Some	commands
     require additional	information, and the user will be prompted
     accordingly.  While typing	this information in, the user's	erase and kill
     keys (as set up by	the command stty) are recognized, and a	newline
     terminates	the input.

     These commands are	currently recognized (^L refers	to control-L):

     ^L	  Redraw the screen.

     h or ?
	  Display a summary of the commands (help screen).

     q	  Quit top.

     d	  Change the number of displays	to show	(prompt	for new	number).
	  Remember that	the next display counts	as one,	so typing d1 will make
	  top show one final display and then immediately exit.

     n or #
	  Change the number of processes to display (prompt for	new number).

     s	  Change the number of seconds to delay	between	displays (prompt for
	  new number).

     k	  Send a signal	("kill"	by default) to a list of processes.  This acts
	  similarly to the command kill(1)).

     r	  Change the priority (the "nice") of a	list of	processes.  This acts
	  similarly to the command renice(8)).

     u	  Display only processes owned by a specific username (prompt for
	  username).  If the username specified	is simply "+", then processes
	  belonging to all users will be displayed.

     e	  Display a list of system errors (if any) generated by	the last kill
	  or renice command.

     i	  (or I) Toggle	the display of idle processes.

BATCH MODE    [Toc]    [Back]

     In	"batch"	mode, all input	from the terminal is ignored.  Interrupt
     characters	(such as ^C and	^\) still have an effect.  This	is the default
     on	a dumb terminal, or when the output is not a terminal.

     By	default	in "batch" mode, only one screen is displayed before top
     automatically exits.

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TOP(1)									TOP(1)

     It	should be noted	that much of the information displayed by top is based
     on	calculations across the	interval between the previous screen and the
     current screen.  If only one screen is displayed, as is the the default
     for "batch" mode, then there is no	previous screen	to use as a base, so
     some of the information will not be available on the first	screen.	 For
     example, it will only display information on processes that are currently
     running, and some of the percentages may be zero.

     To	get more useful	information using "batch" mode,	it is recommended that
     more than one screen be requested.	 For example, the command "top -b -d2"
     will display two screens of information.  The second screen will contain
     more useful information than the first.

THE DISPLAY    [Toc]    [Back]

     The actual	display	varies depending on the	specific variant of Unix that
     the machine is running.  This description may not exactly match what is
     seen by top running on this particular machine.  Differences are listed
     at	the end	of this	manual entry.

     The top few lines of the display show general information about the state
     of	the system, including the last process id assigned to a	process	(on
     most systems), the	three load averages, the current time, the number of
     existing processes, the number of processes in each state (sleeping,
     running, starting,	zombies, and stopped), and a percentage	of time	spent
     in	each of	the processor states (executing	in user	mode, executing	in
     kernel mode, idle,	etc).  It also includes	information about physical and
     virtual memory allocation.

     The remainder of the screen displays information about individual
     processes.	 This display is similar in spirit to ps(1) but	it is not
     exactly the same.	PID is the process id, PGRP is the process group id,
     USERNAME is the name of the process's owner (if -u	is specified, a	UID
     column will be substituted	for USERNAME), PRI is the current priority of
     the process, SIZE is the total size of the	process	(text, data, and
     stack), RES is the	current	amount of resident memory (both	SIZE and RES
     are given in kilobytes), STATE is the current state (one of "sleep",
     "WAIT", "run", "idl", "zomb", or "stop"), TIME is the number of system
     and user cpu seconds that the process has used, WCPU, when	displayed, is
     the weighted cpu percentage (this is the same value that ps(1) displays
     as	CPU), CPU is the raw percentage	and is the field that is sorted	to
     determine the order of the	processes, and COMMAND is the name of the
     command that the process is currently running (if the process is swapped
     out, this column is marked	"<swapped>").

NOTES    [Toc]    [Back]

     The "ABANDONED" state (known in the kernel	as "SWAIT") was	abandoned,
     thus the name.  A process should never end	up in this state.

AUTHOR    [Toc]    [Back]

     William LeFebvre, EECS Department,	Northwestern University

									Page 4

TOP(1)									TOP(1)

ENVIRONMENT    [Toc]    [Back]

     TOP  user-configurable defaults for options.

FILES    [Toc]    [Back]

     /dev/kmem	    kernel memory
     /dev/mem	    physical memory
     /etc/passwd    used to map	uid numbers to user names
     /vmunix	    system image

BUGS    [Toc]    [Back]

     The default for -I	is "do not show	idle processes".  This may be
     confusing if you're expecting top to display a screenful of processes by
     default.  To appease folks	who can't stand	that behavior, I have added
     the ability to set	"default" options in the environment variable TOP (see
     the OPTIONS section).  Those who want idle	processes displayed need only
     set the environment variable TOP to "-I".

     The command name for swapped processes should be tracked down, but	this
     would make	the program run	slower.

     As	with ps(1), things can change while top	is collecting information for
     an	update.	 The picture it	gives is only a	close approximation to

SEE ALSO    [Toc]    [Back]

     kill(1), ps(1), stty(1), mem(4), renice(8)

     Multiprocessor support was	added. Both number of CPUs and the CPU-ID for
     running processes are shown.  On MP systems the sum of %CPU (or %WCPU)
     numbers may be higher than	100% (one full CPU utilization)	but never
     higher than 100 * the number of CPUs.

     The IRIX implementation doesn't nlist(2) the kernel to get	addresses of
     symbols which makes it less system	dependent. All values are retrieved
     using the sysmp(2), syssgi(2), and	proc(4)	interfaces.  The same
     executable	should run on any SGI hardware (Uniprocessor, SMP, and S2MP)
     running IRIX 6.2 and up.

     "last pid"	is not supported.

     A process is considered to	be a "system" process if it has	uid=0 and
     ppid=1. This is a compromise for the sake of backward compatibility.  In
     new IRIX systems many of the traditional "system processes" are
     implemented either	within the kernel as threads, or as real-time

     System processes display can be toggled interactively using the 'S' key.

     Idle processes display can	be toggled interactively using the 'i' key.

									Page 5

TOP(1)									TOP(1)

     Memory sizes are followed by their	units: K (Kilobytes), M	(Megabytes), G
     (Gigabytes) or T (Terabytes).

     The CPU states are	sampled	every clock tick and provide a "best estimate"
     of	the system CPU activity	summed across all processors. On IRIX they

	       idle	 the cpu was idle and not waiting for anything
	       usr	 the cpu was executing some user mode code
	       ker	 the cpu was executing some kernel mode	code
	       wait	 the cpu was idle with some i/o	outstanding
	       xbrk	 the cpu was executing code in a fault path
	       intr	 the cpu was handling an interrupt

     For example: a high "wait"	number means that the system is	I/O bound. A
     close to 100% "usr" number	indicates CPU bound processes with little
     system activity.  "xbrk" and "intr" should	be close to 0.0% under normal
     circumstances. Larger numbers may indicate	pathologically high low-level
     driver activity, memory shortage (high VM activity) etc., in which	case
     osview(1) should give a better picture of the system state.

     The meanings of the idle and wait values changed in the IRIX 6.5.13
     release.  For details, see	the sar(1) man page.

     The PRI (priority)	field supports advanced	IRIX real-time and scheduling
     schemes using the following formats where <pri> is	a decimal priority

	       +<pri>	      Real-Time
	       <pri>	      Normal (timeshared)
	       g<pri>	      Gang scheduled
	       bc	      Batch Critical
	       b	      Batch
	       w	      Weightless

     On	pre 6.4	systems	the supported formats are:

	       +<pri>	      Real-Time
	       <pri>	      Normal (timeshared)
	       b<pri>	      Batch

     For more details on new IRIX scheduling and priorities, see npri(1),
     nice(2), realtime(5), and all the sched_XXX(2) services.

     %WCPU (weighted CPU) is a decaying	average	of %CPU	over a longer period
     than just the last	sampling period. For short running processes %WCPU
     should be close to	%CPU as	the two	values only diverge over time.

     This version of top supports sorting by various fields via	the command
     line -o (order) option or the 'o' interactive option.  The	aliases	'mem'
     (equivalent to 'size'), and 'rss' (equivalent to 'res') are accepted for
     friendliness.  In addition, the IRIX version of top understands prefixes

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TOP(1)									TOP(1)

     of	field names, like '-os', instead of '-osize', to be used.  In case of
     prefix ambiguities, the first one to match	will be	used.  Use 'h' (help)
     to	list the supported orders.

     The old IRIX gr_top is now	implemented as a perl script on	top of the new
     top to reduce bloat. In addition to the -Bcolor option to set the
     background	color, you may now control the foreground color	with -Fcolor,
     and the title bar color with -Tcolor. Colors are either RGB values	or
     Xwindow color names, e.g.	purple.	 (See showrgb for legal	color names.)

     SGI specific "See Also" should include:  osview(1), npri(1), realtime(5),
     and schedctl(2).

     Several more sophisticated	performance tools are optionally provided by
     SGI notably PCP (the Performance CoPilot).

     Unlike other top versions,	the IRIX version should	support	thousands of
     processors	and an even larger number of processes.	 Thus it avoids	preallocating
	a maximum size for process data.  In case the number of
     processes grows too far a new initialization of data structures is
     performed by the program restarting itself.  This restarting forgets any
     interactive settings and may cause	a change in the	Weighted CPU%
     averages.	This should be an extremely rare occurrence but	should be
     noted here.

CREDITS    [Toc]    [Back]

     Original porting to SGI/IRIX 5.x was done by Sandeep Cariapa.  Later
     enhancements and further IRIX ports by Larry McVoy, John Schimmel,	and
     Ariel Faigon.

									PPPPaaaaggggeeee 7777
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