top



TOP(1)                     OpenBSD Reference Manual                     TOP(1)


NAME

     top - display and update information about the top CPU processes


SYNOPSIS

     top [-1bCHIinqSu] [-d count] [-g string] [-o field] [-p pid] [-s time]
         [-U [-]user] [number]


DESCRIPTION

     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
     default.

     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.

     The options are as follows:

     -1      Display combined CPU statistics for all processors on a single
             line instead of one line per CPU.

     -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.

     -C      Show command line arguments as well as the process itself.

     -d count
             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 to be shown before top
             automatically exits.  For intelligent terminals, no upper limit
             is set.  The default is 1 for dumb terminals.

     -g string
             Display only processes that contain string in their command name.

     -H      Show process threads in the display.  Normally, only the main
             process is shown.  This option makes all threads visible.

     -I      Do not display idle processes.  By default, top displays both
             active and idle processes.

     -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.

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

     -o field
             Sort the process display area using the specified field as the
             primary key.  The field name is the name of the column as seen in
             the output, but in lower case.  The OpenBSD version of top
             supports cpu, size, res, time, pri, pid, and command.

     -p pid  Show only the process pid.

     -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.

     -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.

     -s time
             Set the delay between screen updates to time seconds.  The value
             may be fractional, to permit delays of less than 1 second.  The
             default delay between updates is 5 seconds.

     -U [-]user
             Show only those processes owned by user.  The prefix `-' hides
             processes owned by that user.  This option currently only accepts
             usernames and does not understand UID numbers.

     -u      Do not take the time to map UID numbers to usernames.  Normally,
             top will read as much of the password database 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.

     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 idle processes.


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(1)) are recognized, and a newline
     terminates the input.

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

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

     ^L      Redraw the screen.

     <space>
             Update the screen.

     q       Quit top.

     +       Reset any filters put in place by the `g', `p', and `u'
             interactive commands, or their command line equivalents, or any
             process highlighting put in place by the `P' interactive command.

     1       Toggle the display of CPU statistics.

     C       Toggle the display of process command line arguments.

     d count
             Show only count displays, then exit.

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

     g string
             Display only processes that contain string in their command name.
             `g+' shows all processes.

     H       Toggle the display of process threads.

     I | i   Toggle the display of idle processes.

     k [-sig] pid
             Send signal -sig (TERM by default) to process pid.  This acts
             similarly to the command kill(1).

     n|# count
             Show count processes.

     o field
             Sort the process display area using the specified field as the
             primary key.  Values are the same as for the -o flag, as detailed
             above.

     P pid   Highlight a specific process, selected by pid.  `P+' removes
             process highlighting.

     p pid   Show only the process pid.  `p+' shows all processes.

     r count pid
             Change the priority (the nice) of a list of processes to count
             for process pid.  This acts similarly to the command renice(8).

     S       Toggle the display of system processes.

     s time  Set the delay between screen updates to time seconds.

     u [-]user
             Show only those processes owned by user.  `u+' shows processes
             belonging to all users.  The `-' prefix hides processes belonging
             to a single user.


THE DISPLAY

     The top few lines of the display show general information about the state
     of the system, including the three load average numbers, the hostname,
     the current time, the number of existing processes, the number of
     processes in each state (starting, running, idle, stopped, zombie, dead,
     and on processor), and a percentage of time spent in each of the
     processor states (user, nice, system, interrupt, and idle).  It also
     includes information about physical and virtual memory allocation.  The
     load average numbers give the number of jobs in the run queue averaged
     over 1, 5, and 15 minutes.

     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.  The following fields are displayed:

           PID       The process ID.

           USERNAME  The name of the process's owner.

           UID       Used instead of USERNAME if -u is specified.

           PRI       The current priority of the process.

           NICE      The nice amount (in the range -20 to 20).

           SIZE      The total size of the process (the text, data, and stack
                     segments).

           RES       The current amount of resident memory.

           STATE     The current state (one of start, run, sleep, stop, idle,
                     zomb, dead, or onproc).  On multiprocessor systems, this
                     is followed by a slash and the CPU number on which the
                     process is bound.

           WAIT      A description of the wait channel the process is sleeping
                     on if it's asleep.

           TIME      The number of system and user CPU seconds that the
                     process has used.

           CPU       The raw percentage of CPU usage and the default field on
                     which the display is sorted.

           COMMAND   The name of the command that the process is currently
                     running.  (If the process is swapped out, this column is
                     enclosed by angle brackets.)


ENVIRONMENT

     TOP              User-configurable defaults for options.


FILES

     /dev/kmem       kernel memory
     /dev/mem        physical memory
     /etc/passwd     used to map user ID to user
     /bsd            kernel image


SEE ALSO

     fstat(1), kill(1), netstat(1), ps(1), stty(1), systat(1), mem(4),
     iostat(8), pstat(8), renice(8), vmstat(8)


AUTHORS

     William LeFebvre, EECS Department, Northwestern University


BUGS

     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.

OpenBSD 5.4                      June 6, 2012                      OpenBSD 5.4

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