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TOP(1)                        Linux User's Manual                       TOP(1)

       top - display top CPU processes

       top [-] [d delay] [p pid] [q] [c] [C] [S] [s] [i] [n iter] [b]

       top provides an ongoing look at processor activity in real time.  It
       displays a listing of the most CPU-intensive tasks on the system, and
       can provide an interactive interface for manipulating processes.  It
       can sort the tasks by CPU usage, memory usage and runtime.  can be
       better configured than the standard top from the procps suite.  Most
       features can either be selected by an interactive command or by
       specifying the feature in the personal or system-wide configuration
       file. See below for more information.

       d    Specifies the delay between screen updates.  You can change this
            with the s interactive command.

       p    Monitor only processes with given process id.  This flag can be
            given up to twenty times. This option is neither available
            interactively nor can it be put into the configuration file.

       q    This causes top to refresh without any delay. If the caller has
            superuser privileges, top runs with the highest possible priority.

       S    Specifies cumulative mode, where each process is listed with the
            CPU time that it as well as its dead children has spent.  This is
            like the -S flag to ps(1).  See the discussion below of the S
            interactive command.

       s    Tells top to run in secure mode.  This disables the potentially
            dangerous of the interactive commands (see below).  A secure top
            is a nifty thing to leave running on a spare terminal.

       i    Start top ignoring any idle or zombie processes. See the
            interactive command i below.

       C    display total CPU states instead of individual CPUs. This option
            only affects SMP systems.

       c    display command line instead of the command name only. The default
            behavior has been changed as this seems to be more useful.

       H    Show all threads.

       n    Number of iterations. Update the display this number of times and
            then exit.

       b    Batch mode. Useful for sending output from top to other programs
            or to a file.  In this mode, top will not accept command line
            input. It runs until it produces the number of iterations
            requested with the n option or until killed. Output is plain text
            suitable for display on a dumb terminal.

       top displays a variety of information about the processor state.  The
       display is updated every 5 seconds by default, but you can change that
       with the d command-line option or the s interactive command.

            This line displays the time the system has been up, and the three
            load averages for the system.  The load averages are the average
            number of process ready to run during the last 1, 5 and 15
            minutes.  This line is just like the output of uptime(1).  The
            uptime display may be toggled by the interactive l command.

            The total number of processes running at the time of the last
            update.  This is also broken down into the number of tasks which
            are running, sleeping, stopped, or undead. The processes and
            states display may be toggled by the t interactive command.

       CPU states
            Shows the percentage of CPU time in user mode, system mode, niced
            tasks, iowait and idle.  (Niced tasks are only those whose nice
            value is positive.)  Time spent in niced tasks will also be
            counted in system and user time, so the total will be more than
            100%.  The processes and states display may be toggled by the t
            interactive command.

       Mem  Statistics on memory usage, including total available memory, free
            memory, used memory, shared memory, and memory used for buffers.
            The display of memory information may be toggled by the m
            interactive command.

            Statistics on swap space, including total swap space, available
            swap space, and used swap space.  This and Mem are just like the
            output of free(1).

       PID  The process ID of each task.

            The parent process ID each task.

       UID  The user ID of the task's owner.

            The user name of the task's owner.

       PRI  The priority of the task.

       NI   The nice value of the task.  Negative nice values are higher

            The size of the task's code plus data plus stack space, in
            kilobytes, is shown here.

            The code size of the task. This gives strange values for kernel
            processes and is broken for ELF processes.

            Data + Stack size. This is broken for ELF processes.

       TRS  Text resident size.

            Size of the swapped out part of the task.

       D    Size of pages marked dirty.

       LC   Last used processor.  (That this changes from time to time is not
            a bug; Linux intentionally uses weak affinity.  Also notice that
            the very act of running top may break weak affinity and cause more
            processes to change current CPU more often because of the extra
            demand for CPU time.)

       RSS  The total amount of physical memory used by the task, in
            kilobytes, is shown here. For ELF processes used library pages are
            counted here, for a.out processes not.

            The amount of shared memory used by the task is shown in this

            The state of the task is shown here. The state is either S for
            sleeping, D for uninterruptible sleep, R for running, Z for
            zombies, or T for stopped or traced. These states are modified by
            trailing < for a process with negative nice value, N for a process
            with positive nice value, W for a swapped out process (this does
            not work correctly for kernel processes).

            depending on the availability of either /boot/psdatabase or the
            kernel link map /boot/ this shows the address or the
            name of the kernel function the task currently is sleeping in.

            Total CPU time the task has used since it started.  If cumulative
            mode is on, this also includes the CPU time used by the process's
            children which have died.  You can set cumulative mode with the S
            command line option or toggle it with the interactive command S.
            The header line will then be changed to CTIME.

            The task's share of the CPU time since the last screen update,
            expressed as a percentage of total CPU time per processor.

            The task's share of the physical memory.

            The task's command name, which will be truncated if it is too long
            to be displayed on one line.  Tasks in memory will have a full
            command line, but swapped-out tasks will only have the name of the
            program in parentheses (for example, "(getty)").

       A , WP
            these fields from the kmem top are not supported.

       Several single-key commands are recognized while top is running.  Some
       are disabled if the s option has been given on the command line.

            Immediately updates the display.

       ^L   Erases and redraws the screen.

       h or ?
            Displays a help screen giving a brief summary of commands, and the
            status of secure and cumulative modes.

       k    Kill a process.  You will be prompted for the PID of the task, and
            the signal to send to it.  For a normal kill, send signal 15.  For
            a sure, but rather abrupt, kill, send signal 9.  The default
            signal, as with kill(1), is 15, SIGTERM.  This command is not
            available in secure mode.

       i    Ignore idle and zombie processes.  This is a toggle switch.

       I    Toggle between Solaris (CPU percentage divided by total number of
            CPUs) and Irix (CPU percentage calculated solely by amount of
            time) views.  This is a toggle switch that affects only SMP

       n or #
            Change the number of processes to show.  You will be prompted to
            enter the number.  This overrides automatic determination of the
            number of processes to show, which is based on window size
            measurement.  If 0 is specified, then top will show as many
            processes as will fit on the screen; this is the default.

       q    Quit.

       r    Re-nice a process.  You will be prompted for the PID of the task,
            and the value to nice it to.  Entering a positve value will cause
            a process to be niced to negative values, and lose priority.  If
            root is running top, a negative value can be entered, causing a
            process to get a higher than normal priority.  The default renice
            value is 10.  This command is not available in secure mode.

       S    This toggles cumulative mode, the equivalent of ps -S, i.e., that
            CPU times will include a process's defunct children.  For some
            programs, such as compilers, which work by forking into many
            separate tasks, normal mode will make them appear less demanding
            than they actually are.  For others, however, such as shells and
            init, this behavior is correct.  In any case, try cumulative mode
            for an alternative view of CPU use.

       s    Change the delay between updates.  You will be prompted to enter
            the delay time, in seconds, between updates.  Fractional values
            are recognized down to microseconds.  Entering 0 causes continuous
            updates.  The default value is 5 seconds.  Note that low values
            cause nearly unreadably fast displays, and greatly raise the load.
            This command is not available in secure mode.

       f or F
            Add fields to display or remove fields from the display. See below
            for more information.

       o or O
            Change order of displayed fields. See below for more information.

       l    toggle display of load average and uptime information.

       m    toggle display of memory information.

       t    toggle display of processes and CPU states information.

       c    toggle display of command name or full command line.

       N    sort tasks by pid (numerically).

       A    sort tasks by age (newest first).

       P    sort tasks by CPU usage (default).

       M    sort tasks by resident memory usage.

       T    sort tasks by time / cumulative time.

       W    Write current setup to ~/.toprc.  This is the recommended way to
            write a top configuration file.

The Field and Order Screens
       After pressing f, F, o or O you will be shown a screen specifying the
       field order on the top line and short descriptions of the field
       contents. The field order string uses the following syntax: If the
       letter in the filed string corresponding to a  field is upper case, the
       field will be displayed.  This is furthermore indicated by an asterisk
       in front of the field description.  The order of the fields corresponds
       to the order of the letters in the string.
        From the field select screen you can toggle the display of a field by
       pressing the corresponding letter.
        From the order screen you may move a field to the left by pressing the
       corresponding upper case letter resp. to the right by pressing the
       lower case one.

Configuration Files
       Top reads it's default configuration from two files, /etc/toprc and
       ~/.toprc.  The global configuration file may be used to restrict the
       usage of top to the secure mode for non-non-privileged users. If this
       is desired, the file should contain a 's' to specify secure mode and a
       digit d (2<=d<=9) for the default delay (in seconds) on a single line.
       The personal configuration file contains two lines. The first line
       contains lower and upper letters to specify which fields in what order
       are to be displayed. The letters correspond to the letters in the
       Fields or Order screens from top. As this is not very instructive, it
       is recommended to select fields and order in a running top process and
       to save this using the W interactive command.  The second line is more
       interesting (and important). It contains information on the other
       options. Most important, if you have saved a configuration in secure
       mode, you will not get an insecure top without removing the lower 's'
       from the second line of your ~/.toprc.  A digit specifies the delay
       time between updates, a capital 'S' cumulative mode, a lower 'i' no-
       idle mode, a capital 'I' Irix view. As in interactive mode, a lower
       'm', 'l', and 't' suppresses the display of memory, uptime resp.
       process and CPU state information.  Currently changing the default
       sorting order (by CPU usage) is not supported.

       This proc-based top works by reading the files in the proc filesystem,
       mounted on /proc.  If /proc is not mounted, top will not work.

       %CPU shows the cputime/realtime percentage in the period of time
       between updates.  For the first update, a short delay is used, and top
       itself dominates the CPU usage.  After that, top will drop back, and a
       more reliable estimate of CPU usage is available.

       The SIZE and RSS fields don't count the page tables and the task_struct
       of a process; this is at least 12K of memory that is always resident.
       SIZE is the virtual size of the process (code+data+stack).

       Keep in mind that a process must die for its time to be recorded on its
       parent by cumulative mode.  Perhaps more useful behavior would be to
       follow each process upwards, adding time, but that would be more
       expensive, possibly prohibitively so.  In any case, that would make
       top's behavior incompatible with ps.

       /etc/toprc The global configuration file.  ~/.toprc The personal
       configuration file.

       ps(1), free(1), uptime(1), kill(1), renice(1).

       If the window is less than about 70x7, top will not format information
        Many fields still have problems with ELF processes.
        the help screens are not yet optimized for windows with less than 25

       top was originally written by Roger Binns, based on Branko Lankester's
       <> ps program.  Robert Nation
       <> re-wrote it significantly to use
       the proc filesystem, based on Michael K. Johnson's
       <> proc-based ps program.  Michael Shields
       <> made many changes, including secure and
       cumulative modes and a general cleanup.  Tim Janik <> added
       age sorting and the ability to monitor specific processes through their

       Helmut Geyer <> Heavily changed it to
       include support for configurable fields and other new options, and did
       further cleanup and use of the new readproc interface.

       The "b" and "n" options contributed by George Bonser
       <> for CapTech IT Services.

       Michael K. Johnson <> is now the maintainer.

       Please send bug reports to <>

Linux                             Feb 1 1993                            TOP(1)


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