TOP(1) RISC/os Reference Manual TOP(1)
NAME
top - display and update information about the top cpu
processes
SYNOPSIS
top [ -Sbinu ] [ -dcount ] [ -stime ] [ number ]
DESCRIPTION
Top displays the top processes on the system and periodi-
cally 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 default.
Top makes a distinction between terminals that support
advanced capabilities and those that do not. This distinc-
tion 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
-S Show system processes in the display. Normally, system
processes such as the pager and the swapper are not
shown. This option makes them visible.
-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 pro-
cessed, the screen will immediately be updated, even if
the command was not understood. This mode is the
default when standard output is an intelligent termi-
nal.
-n Use "non-interactive" mode. This is indentical to
"batch" mode.
-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
Printed 11/19/92 Page 1
TOP(1) RISC/os Reference Manual TOP(1)
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.
-dcount
Show only count displays, then exit. A display is con-
sidered 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 dumb terminals.
-stime
Set the delay between screen updates to time seconds.
The default delay between updates is 5 seconds.
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.
INTERACTIVE MODE
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 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
Page 2 Printed 11/19/92
TOP(1) RISC/os Reference Manual TOP(1)
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 ren-
ice(8)).
e Display a list of system errors (if any) generated by
the last kill or renice command.
THE DISPLAY
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, the three load averages, the current
time, the number of existing processes, the number of
processes in each state (sleeping, ABANDONED, running,
starting, zombies, and stopped), and a percentage of time
spent in each of the processor states (user, nice, system,
and idle). It also includes the amount of virtual and real
memory in use (with the amount of memory considered "active"
in parentheses) and the amount of free memory.
The remainder of the screen displays information about indi-
vidual processes. This display is similar in spirit to
ps(1) but it is not exactly the same. PID is the process
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, NICE is the nice
amount (in the range -20 to 20), 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 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>").
Printed 11/19/92 Page 3
TOP(1) RISC/os Reference Manual TOP(1)
NOTES
The "ABANDONED" state (known in the kernel as "SWAIT") was
abandoned, thus the name. A process should never end up in
this state.
AUTHOR
William LeFebvre, Rice University graduate student
FILES
/dev/kmem kernel memory
/dev/mem physical memory
/etc/passwd used to map uid numbers to user names
/vmunix system image
BUGS
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 reality.
SEE ALSO
kill(1), ps(1), stty(1), mem(4), renice(8)
Page 4 Printed 11/19/92