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



NAME
       top - display Linux tasks



SYNOPSIS
       top -hv | -abcHimMsS -d delay -n iterations -p pid [, pid ...]

       The traditional switches '-' and whitespace are optional.



DESCRIPTION
       The top program provides a dynamic real-time view of a running system.  It can dis-
       play system summary information as well as a list of tasks currently being  managed
       by  the Linux kernel.  The types of system summary information shown and the types,
       order and size of information displayed for tasks are  all  user  configurable  and
       that configuration can be made persistent across restarts.

       The  program  provides  a limited interactive interface for process manipulation as
       well as a much more extensive interface for personal configuration  --   encompass-
       ing  every  aspect  of its operation.  And while top is referred to throughout this
       document, you are free to name the program anything you wish.  That new name,  pos-
       sibly  an  alias, will then be reflected on top's display and used when reading and
       writing a configuration file.



OVERVIEW
   Documentation
       The remaining Table of Contents
           1. COMMAND-LINE Options
           2. FIELDS / Columns
              a. DESCRIPTIONS of Fields
              b. SELECTING and ORDERING Columns
           3. INTERACTIVE Commands
              a. GLOBAL Commands
              b. SUMMARY Area Commands
              c. TASK Area Commands
              d. COLOR Mapping
           4. ALTERNATE-DISPLAY Mode
              a. WINDOWS Overview
              b. COMMANDS for Windows
           5. FILES
              a. SYSTEM Configuration File
              b. PERSONAL Configuration File
           6. STUPID TRICKS Sampler
              a. Kernel Magic
              b. Bouncing Windows
              c. The Big Bird Window
           7. BUGS, 8. HISTORY Former top, 9. AUTHOR, 10. SEE ALSO


   Operation
       When operating top, the two most important keys are help  ('h'  or  '?')  and  quit
       ('q')  key.   Alternatively,  you  could  simply  use the traditional interrupt key
       ('^C') when you're done.

       When you start top for the first time, you'll be  presented  with  the  traditional
       screen  elements:  1)  Summary  Area; 2) Message/Prompt Line; 3) Columns Header; 4)
       Task Area.  There will, however, be some differences when compared  to  the  former
       top.


       Highlighting
          Summary_Area: There is no highlighting for load/uptime and only values are high-
          lighted for other elements.

          Task_Area: Tasks running (or ready to run) will be highlighted, and bold is only
          one way of emphasizing such processes.


       Content/Labels
          Summary_Area: The program name is shown, perhaps a symlink or alias.  The Cpu(s)
          state label hints at other possibilities.  The memory stats  use  a  lower  case
          'k'.

          Columns_Header:  Will show a new field and some changed labels.  More new fields
          will be found as you customize your top.


       Note: the width of top's display will be limited to 512 positions.  Displaying  all
       fields requires a minimum of 160 characters.  The remaining width could be used for
       the 'Command' column.


   Startup Defaults
       The following startup defaults assume no configuration  file,  thus  no  user  cus-
       tomizations.   Even  so,  items  shown  with  an asterisk ('*') could be overridden
       through the command-line.

           Global_defaults
              'A' - Alt display      Off (full-screen)
            * 'd' - Delay time       3.0 seconds
              'I' - Irix mode        On  (no, 'solaris' smp)
            * 'p' - PID monitoring   Off
            * 's' - Secure mode      Off (unsecured)
              'B' - Bold disable     Off
           Summary_Area_defaults
              'l' - Load Avg/Uptime  On  (thus program name)
              't' - Task/Cpu states  On  (1+1 lines, see '1')
              'm' - Mem/Swap usage   On  (2 lines worth)
              '1' - Single Cpu       On  (thus 1 line if smp)
           Task_Area_defaults
              'b' - Bold hilite      On  (not 'reverse')
            * 'c' - Command line     Off (name, not cmdline)
            * 'H' - Threads          Off (show all threads)
            * 'i' - Idle tasks       On  (show all tasks)
              'R' - Reverse sort     On  (pids high-to-low)
            * 'S' - Cumulative time  Off (no, dead children)
              'x' - Column hilite    Off (no, sort field)
              'y' - Row hilite       On  (yes, running tasks)
              'z' - color/mono       Off (no, colors)



1. COMMAND-LINE Options
       The command-line syntax for top consists of:

            -hv | -abcHimMsS -d delay -n iterations -p pid [,pid...]

       The typically mandatory switches ('-') and even whitespace are completely optional.


       -a : Sort by memory usage
            This switch makes top to sort the processes by allocated memory


       -b : Batch mode operation
            Starts  top in 'Batch mode', which could be useful for sending output from top
            to other programs or to a file.  In this mode, top will not accept  input  and
            runs  until  the iterations limit you've set with the '-n' command-line option
            or until killed.


       -c : Command line/Program name toggle
            Starts top with the last remembered 'c' state reversed.  Thus, if top was dis-
            playing command lines, now that field will show program names, and visa versa.
            See the 'c' interactive command for additional information.


       -d : Delay time interval as:  -d ss.tt (seconds.tenths)
            Specifies the delay between screen updates, and  overrides  the  corresponding
            value in one's personal configuration file or the startup default.  Later this
            can be changed with the 'd' or 's' interactive commands.

            Fractional seconds are honored, but a negative number is not allowed.  In  all
            cases,  however,  such  changes  are  prohibited  if top is running in 'Secure
            mode', except for root (unless the 's' command-line  option  was  used).   For
            additional  information  on  'Secure  mode' see topic 5a. SYSTEM Configuration
            File.


       -h : Help
            Show library version and the usage prompt, then quit.


       -H : Threads toggle
            Starts top with the last remembered 'H' state reversed.  When this  toggle  is
            On,  all individual threads will be displayed.  Otherwise, top displays a sum-
            mation of all threads in a process.


       -i : Idle Processes toggle
            Starts top with the last remembered 'i' state reversed.  When this  toggle  is
            Off, tasks that are idled or zombied will not be displayed.


       -m : VIRT/USED toggle
            Reports USED (sum of process rss and swap total count) instead of VIRT


       -M : Detect memory units
            Show memory units (k/M/G) and display floating point values in the memory sum-
            mary.


       -n : Number of iterations limit as:  -n number
            Specifies the maximum number of iterations,  or  frames,  top  should  produce
            before ending.


       -p : Monitor PIDs as:  -pN1 -pN2 ...  or  -pN1, N2 [,...]
            Monitor  only  processes with specified process IDs.  This option can be given
            up to 20 times, or you can provide a comma delimited list with up to 20  pids.
            Co-mingling both approaches is permitted.

            This  is  a command-line option only.  And should you wish to return to normal
            operation, it is not necessary to quit and and restart top  --  just issue the
            '=' interactive command.


       -s : Secure mode operation
            Starts  top  with  secure mode forced, even for root.  This mode is far better
            controlled through the system configuration file (see topic 5. FILES).


       -S : Cumulative time mode toggle
            Starts top with the last remembered  'S'  state  reversed.   When  'Cumulative
            mode'  is  On,  each  process is listed with the cpu time that it and its dead
            children have used.  See the 'S' interactive command for  additional  informa-
            tion regarding this mode.


       -u : Monitor by user as:  -u somebody
            Monitor only processes with an effective UID or user name matching that given.


       -U : Monitor by user as:  -U somebody
            Monitor only processes with a UID or user  name  matching  that  given.   This
            matches real, effective, saved, and filesystem UIDs.


       -v : Version
            Show library version and the usage prompt, then quit.


2. FIELDS / Columns
   2a. DESCRIPTIONS of Fields
       Listed  below are top's available fields.  They are always associated with the let-
       ter shown, regardless of the position you may have established for  them  with  the
       'o' (Order fields) interactive command.

       Any  field is selectable as the sort field, and you control whether they are sorted
       high-to-low or low-to-high.  For additional  information  on  sort  provisions  see
       topic 3c. TASK Area Commands.


       a: PID  --  Process Id
          The  task's unique process ID, which periodically wraps, though never restarting
          at zero.


       b: PPID  --  Parent Process Pid
          The process ID of a task's parent.


       c: RUSER  --  Real User Name
          The real user name of the task's owner.


       d: UID  --  User Id
          The effective user ID of the task's owner.


       e: USER  --  User Name
          The effective user name of the task's owner.


       f: GROUP  --  Group Name
          The effective group name of the task's owner.


       g: TTY  --  Controlling Tty
          The name of the controlling terminal.  This is usually the device (serial  port,
          pty,  etc.)  from  which the process was started, and which it uses for input or
          output.  However, a task need not be associated with a terminal, in  which  case
          you'll see '?' displayed.


       h: PR  --  Priority
          The priority of the task.


       i: NI  --  Nice value
          The  nice  value  of  the  task.   A  negative nice value means higher priority,
          whereas a positive nice value means lower priority.  Zero in this  field  simply
          means priority will not be adjusted in determining a task's dispatchability.


       j: P  --  Last used CPU (SMP)
          A  number  representing the last used processor.  In a true SMP environment this
          will likely change frequently since the kernel intentionally uses weak affinity.
          Also,  the  very  act of running top may break this weak affinity and cause more
          processes to change CPUs more often (because of the extra demand for cpu  time).


       k: %CPU  --  CPU usage
          The task's share of the elapsed CPU time since the last screen update, expressed
          as a percentage of total CPU time.  In a true SMP environment, if 'Irix mode' is
          Off, top will operate in 'Solaris mode' where a task's cpu usage will be divided
          by the total number of CPUs.  You  toggle  'Irix/Solaris'  modes  with  the  'I'
          interactive command.


       l: TIME  --  CPU Time
          Total  CPU  time  the task has used since it started.  When 'Cumulative mode' is
          On, each process is listed with the cpu time that it and its dead  children  has
          used.  You toggle 'Cumulative mode' with 'S', which is a command-line option and
          an interactive command.  See the 'S' interactive command for additional informa-
          tion regarding this mode.


       m: TIME+  --  CPU Time, hundredths
          The same as 'TIME', but reflecting more granularity through hundredths of a sec-
          ond.


       n: %MEM  --  Memory usage (RES)
          A task's currently used share of available physical memory.


       o: VIRT  --  Virtual Image (kb)
          The total amount of virtual memory used by the task.  It includes all code, data
          and  shared  libraries  plus  pages  that  have been swapped out. (Note: you can
          define the STATSIZE=1 environment variable and the VIRT will be calculated  from
          the /proc/#/state VmSize field.)


       p: SWAP  --  Swapped size (kb)
          Per-process swap values are now taken from /proc/#/status VmSwap field.


       q: RES  --  Resident size (kb)
          The non-swapped physical memory a task is using.


       r: CODE  --  Code size (kb)
          The  amount  of  physical  memory  devoted to executable code, also known as the
          'text resident set' size or TRS.


       s: DATA  --  Data+Stack size (kb)
          The amount of physical memory devoted to other than executable code, also  known
          as the 'data resident set' size or DRS.


       t: SHR  --  Shared Mem size (kb)
          The  amount  of  shared  memory  used by a task.  It simply reflects memory that
          could be potentially shared with other processes.


       u: nFLT  --  Page Fault count
          The number of major page faults that have occurred for a  task.   A  page  fault
          occurs  when  a process attempts to read from or write to a virtual page that is
          not currently present in its address space.  A major page  fault  is  when  disk
          access is involved in making that page available.


       v: nDRT  --  Dirty Pages count
          The  number  of  pages  that  have been modified since they were last written to
          disk.  Dirty pages must be written to disk  before  the  corresponding  physical
          memory location can be used for some other virtual page.


       w: S  --  Process Status
          The status of the task which can be one of:
             'D' = uninterruptible sleep
             'R' = running
             'S' = sleeping
             'T' = traced or stopped
             'Z' = zombie

          Tasks shown as running should be more properly thought of as 'ready to run'  --
          their task_struct is simply represented on the Linux run-queue.  Even without  a
          true  SMP  machine,  you may see numerous tasks in this state depending on top's
          delay interval and nice value.


       x: Command  --  Command line or Program name
          Display the command line used to start a task or the name of the associated pro-
          gram.   You  toggle between command line and name with 'c', which is both a com-
          mand-line option and an interactive command.

          When you've chosen to display command lines, processes without  a  command  line
          (like  kernel  threads) will be shown with only the program name in parentheses,
          as in this example:
                ( mdrecoveryd )

          Either form of display is subject to potential truncation if it's  too  long  to
          fit  in  this  field's  current  width.   That  width  depends upon other fields
          selected, their order and the current screen width.

          Note: The 'Command' field/column is unique, in that it is not fixed-width.  When
          displayed,  this  column will be allocated all remaining screen width (up to the
          maximum 512 characters) to provide for the potential  growth  of  program  names
          into command lines.


       y: WCHAN  --  Sleeping in Function
          Depending  on the availability of the kernel link map ('System.map'), this field
          will show the name or the address of the kernel function in which  the  task  is
          currently sleeping.  Running tasks will display a dash ('-') in this column.

          Note:  By displaying this field, top's own working set will be increased by over
          700Kb.  Your only means of reducing that overhead will be to  stop  and  restart
          top.


       z: Flags  --  Task Flags
          This  column  represents the task's current scheduling flags which are expressed
          in hexadecimal notation and with zeros suppressed.  These flags  are  officially
          documented  in  <linux/sched.h>.  Less formal documentation can also be found on
          the 'Fields select' and 'Order fields' screens.


   2b. SELECTING and ORDERING Columns
       After pressing the interactive commands 'f' (Fields select) or ?o'  (Order  fields)
       you  will  be shown a screen containing the current fields string followed by names
       and descriptions for all fields.

       Here is a sample fields string from one of top's four windows/field groups  and  an
       explanation of the conventions used:

       -  Sample fields string:
             ANOPQRSTUVXbcdefgjlmyzWHIK

       -  The  order  of  displayed fields corresponds to the order of the letters in that
          string.

       -  If the letter is upper case the corresponding field itself will then be shown as
          part of the task display (screen width permitting).  This will also be indicated
          by a leading asterisk ('*'), as in this excerpt:
              ...
              * K: %CPU       = CPU usage
                l: TIME       = CPU Time
                m: TIME+      = CPU Time, hundredths
              * N: %MEM       = Memory usage (RES)
              * O: VIRT       = Virtual Image (kb)
              ...


       Fields select screen  --  the 'f' interactive command
          You toggle the display of a field by simply pressing the corresponding letter.


       Order fields screen  --  the 'o' interactive command
          You move a field to the left by pressing the corresponding upper case letter and
          to the right with the lower case letter.


   2c. SUMMARY Area Fields
       The  summary  area  fields describing CPU statistics are abbreviated.  They provide
       information about times spent in:
           us = user mode
           sy = system mode
           ni = low priority user mode (nice)
           id = idle task
           wa = I/O waiting
           hi = servicing IRQs
           si = servicing soft IRQs
           st = steal (time given to other DomU instances)



3. INTERACTIVE Commands
       Listed below is a brief index of commands within categories.  Some commands  appear
       more  than  once   --   their meaning or scope may vary depending on the context in
       which they are issued.

         3a. GLOBAL_Commands
               <Ret/Sp> ?, =, A, B, d, G, h, I, k, q, r, s, W, Z
         3b. SUMMARY_Area_Commands
               l, m, t, 1
         3c. TASK_Area_Commands
               Appearance:  b, x, y, z
               Content:     c, f, H, o, S, u
               Size:        #, i, n
               Sorting:     <, >, F, O, R
         3d. COLOR_Mapping
               <Ret>, a, B, b, H, M, q, S, T, w, z, 0 - 7
         4b. COMMANDS_for_Windows
               -, _, =, +, A, a, G, g, w


   3a. GLOBAL Commands
       The global interactive commands are always available in both full-screen  mode  and
       alternate-display  mode.   However,  some  of  these  interactive  commands are not
       available when running in 'Secure mode'.

       If you wish to know in advance whether or not your top has been secured, simply ask
       for help and view the system summary on the second line.


         <Enter> or <Space> :Refresh_Display
              These  commands  do  nothing,  they  are simply ignored.  However, they will
              awaken top and following receipt of any input the  entire  display  will  be
              repainted.

              Use  either of these keys if you have a large delay interval and wish to see
              current status,


         ??? or ?h? :Help
              There are two help levels available.  The first will provide a  reminder  of
              all  the basic interactive commands.  If top is secured, that screen will be
              abbreviated.

              Typing 'h' or '?' on that help screen will take you to help for those inter-
              active commands applicable to alternate-display mode.


         ?=? :Exit_Task_Limits
              Removes  restrictions  on  which tasks are shown.  This command will reverse
              any 'i' (idle tasks) and 'n' (max tasks) commands that might be active.   It
              also  provides for an 'exit' from PID monitoring.  See the '-p' command-line
              option for a discussion of PID monitoring.

              When operating in alternate-display mode this command has a slightly broader
              meaning.


         ?A? :Alternate_Display_Mode_toggle
              This  command  will  switch  between  full-screen mode and alternate-display
              mode.  See topic 4. ALTERNATE-DISPLAY Mode and the 'G'  interactive  command
              for insight into ?current' windows and field groups.


         ?B? :Bold_Disable/Enable_toggle
              This command will influence use of the 'bold' terminfo capability and alters
              both the summary area and task area for the ?current' window.  While  it  is
              intended primarily for use with dumb terminals, it can be applied anytime.

              Note:  When  this  toggle is On and top is operating in monochrome mode, the
              entire display will appear as normal text.  Thus, unless the 'x' and/or  'y'
              toggles are using reverse for emphasis, there will be no visual confirmation
              that they are even on.


       * ?d? or ?s? :Change_Delay_Time_interval
              You will be prompted to enter the delay time, in  seconds,  between  display
              updates.

              Fractional  seconds  are  honored,  but  a  negative  number is not allowed.
              Entering 0 causes (nearly) continuous updates, with an  unsatisfactory  dis-
              play  as  the  system and tty driver try to keep up with top's demands.  The
              delay value is inversely proportional to system  loading,  so  set  it  with
              care.

              If  at any time you wish to know the current delay time, simply ask for help
              and view the system summary on the second line.


         ?G? :Choose_Another_Window/Field_Group
              You will be prompted to enter a number between 1 and 4 designating the  win-
              dow/field  group  which  should be made the ?current' window.  You will soon
              grow comfortable with these 4 windows, especially after  experimenting  with
              alternate-display mode.


         ?I? :Irix/Solaris_Mode_toggle
              When  operating in 'Solaris mode' ('I' toggled Off), a task's cpu usage will
              be divided by the total number of CPUs.  After issuing this command,  you'll
              be informed of the new state of this toggle.


         ?u? :select a user
              You  will be prompted for a UID or username. Only processes belonging to the
              selected user will be displayed. This option matches on the effective UID.


         ?U? :select a user
              You will be prompted for a UID or username. Only processes belonging to  the
              selected user will be displayed. This option matches on the real, effective,
              saved, and filesystem UID.


       * ?k? :Kill_a_task
              You will be prompted for a PID and then the signal  to  send.   The  default
              signal,  as  reflected in the prompt, is SIGTERM.  However, you can send any
              signal, via number or name.

              If you wish to abort the kill process, do one of the following depending  on
              your progress:
                 1) at the pid prompt, just press <Enter>
                 2) at the signal prompt, type 0


         ?q? :Quit


       * ?r? :Renice_a_Task
              You will be prompted for a PID and then the value to nice it to.  Entering a
              positive value will cause a process to lose priority.  Conversely,  a  nega-
              tive value will cause a process to be viewed more favorably by the kernel.


         ?W? :Write_the_Configuration_File
              This will save all of your options and toggles plus the current display mode
              and delay time.  By issuing this command just before quitting top, you  will
              be able restart later in exactly that same state.


         ?Z? :Change_Color_Mapping
              This  key will take you to a separate screen where you can change the colors
              for the ?current' window, or for all windows.  For  details  regarding  this
              interactive command see topic 3d. COLOR Mapping.


       *  The  commands  shown  with an asterisk ('*') are not available in 'Secure mode',
          nor will they be shown on the level-1 help screen.


   3b. SUMMARY Area Commands
       The summary area interactive commands are always available in both full-screen mode
       and  alternate-display  mode.   They affect the beginning lines of your display and
       will determine the position of messages and prompts.

       These commands always impact just the ?current' window/field group.  See  topic  4.
       ALTERNATE-DISPLAY  Mode  and the 'G' interactive command for insight into ?current'
       windows and field groups.


         ?l? :Toggle_Load_Average/Uptime  --  On/Off
              This is also the line containing the program name (possibly an  alias)  when
              operating in full-screen mode or the ?current' window name when operating in
              alternate-display mode.


         ?m? :Toggle_Memory/Swap_Usage  --  On/Off
              This command affects two summary area lines.


         ?t? :Toggle_Task/Cpu_States  --  On/Off
              This command affects from 2 to many summary area  lines,  depending  on  the
              state of the '1' toggle and whether or not top is running under true SMP.


         ?1? :Toggle_Single/Separate_Cpu_States  --  On/Off
              This  command  affects  how  the  't' command's Cpu States portion is shown.
              Although this  toggle  exists  primarily  to  serve  massively-parallel  SMP
              machines, it is not restricted to solely SMP environments.

              When you see 'Cpu(s):' in the summary area, the '1' toggle is On and all cpu
              information is gathered in a single line.  Otherwise, each cpu is  displayed
              separately as: 'Cpu0, Cpu1, ...'


       Note:  If the entire summary area has been toggled Off for any window, you would be
       left with just the message line.  In that way, you will  have  maximized  available
       task  rows but (temporarily) sacrificed the program name in full-screen mode or the
       ?current' window name when in alternate-display mode.


   3c. TASK Area Commands
       The task area interactive commands are always available in full-screen mode.

       The task area interactive commands are never available in alternate-display mode if
       the  ?current'  window's  task  display  has  been toggled Off (see topic 4. ALTER-
       NATE-DISPLAY Mode).


       APPEARANCE of task window
         The following commands will also be influenced by the state  of  the  global  'B'
         (bold disable) toggle.


         ?b? :Bold/Reverse_toggle
              This  command  will  impact how the 'x' and 'y' toggles are displayed.  Fur-
              ther, it will only be available when at least one of those toggles is On.


         ?x? :Column_Highlight_toggle
              Changes highlighting for the current sort field.  You probably don't need  a
              constant visual reminder of the sort field and top hopes that you always run
              with 'column highlight' Off, due to the cost in path-length.

              If you forget which field is being sorted this command can serve as a  quick
              visual reminder.


         ?y? :Row_Highlight_toggle
              Changes  highlighting for "running" tasks.  For additional insight into this
              task state, see topic 2a. DESCRIPTIONS of Fields, Process Status.

              Use of this provision provides important insight into your system's  health.
              The only costs will be a few additional tty escape sequences.


         ?z? :Color/Monochrome_toggle
              Switches  the  ?current'  window between your last used color scheme and the
              older form of black-on-white or white-on-black.   This  command  will  alter
              both  the  summary  area  and task area but does not affect the state of the
              'x', 'y' or 'b' toggles.


       CONTENT of task window
         ?c? :Command_Line/Program_Name_toggle
              This command will be honored whether or not the  'Command'  column  is  cur-
              rently  visible.   Later,  should  that field come into view, the change you
              applied will be seen.

         ?f? and ?o? :Fields_select or Order_fields
              These keys display separate screens where you can change  which  fields  are
              displayed  and their order.  For additional information on these interactive
              commands see topic 2b. SELECTING and ORDERING Columns.

         ?H? :Threads_toggle
              When this toggle is On, all individual threads will  be  displayed.   Other-
              wise, top displays a summation of all threads in a process.

         ?S? :Cumulative_Time_Mode_toggle
              When  'Cumulative mode' is On, each process is listed with the cpu time that
              it and its dead children have used.

              When Off, programs that fork into  many  separate  tasks  will  appear  less
              demanding.   For programs like 'init' or a shell this is appropriate but for
              others, like compilers, perhaps not.  Experiment with two task windows shar-
              ing  the  same sort field but with different 'S' states and see which repre-
              sentation you prefer.

              After issuing this command, you'll be informed of the new state of this tog-
              gle.   If you wish to know in advance whether or not 'Cumulative mode' is in
              effect, simply ask for help and view the window summary on the second  line.

         ?u? :Show_Specific_User_Only
              You  will be prompted to enter the name of the user to display.  Thereafter,
              in that task window only matching User ID's will be shown,  or  possibly  no
              tasks will be shown.

              Later,  if  you  wish  to monitor all tasks again, re-issue this command but
              just press <Enter> at the prompt, without providing a name.

       SIZE of task window
         ?i? :Idle_Processes_toggle
              Displays all tasks or just active tasks.  When this toggle is Off, idled  or
              zombied processes will not be displayed.

              If  this  command is applied to the last task display when in alternate-dis-
              play mode, then it will not affect the window's size, as all prior task dis-
              plays will have already been painted.

         ?n? or ?#? :Set_Maximum_Tasks
              You will be prompted to enter the number of tasks to display.  The lessor of
              your number and available screen rows will be used.

              When used in alternate-display mode, this is the command that gives you pre-
              cise  control  over  the size of each currently visible task display, except
              for the very last.  It will not affect the last window's size, as all  prior
              task displays will have already been painted.

              Note: If you wish to increase the size of the last visible task display when
              in alternate-display mode, simply decrease the size of the  task  display(s)
              above it.

       SORTING of task window
         For  compatibility,  this  top  supports most of the former top sort keys.  Since
         this is primarily a service to former top users, these commands do not appear  on
         any help screen.
            command   sorted field                  supported
              A         start time (non-display)      No
              M         %MEM                          Yes
              N         PID                           Yes
              P         %CPU                          Yes
              T         TIME+                         Yes

         Before  using  any  of  the following sort provisions, top suggests that you tem-
         porarily turn on column highlighting using the  'x'  interactive  command.   That
         will help ensure that the actual sort environment matches your intent.

         The  following  interactive  commands  will only be honored when the current sort
         field is visible.  The sort field might not be visible because:
              1) there is insufficient Screen Width
              2) the 'f' interactive command turned it Off

         ?<? :Move_Sort_Field_Left
              Moves the sort column to the left unless the current sort field is the first
              field being displayed.

         ?>? :Move_Sort_Field_Right
              Moves the sort column to the right unless the current sort field is the last
              field being displayed.

         The following interactive commands will always be honored whether or not the cur-
         rent sort field is visible.

         ?F? or ?O? :Select_Sort_Field
              These  keys  display  a  separate screen where you can change which field is
              used as the sort column.

              If a field is selected which was not previously being displayed, it will  be
              forced  On when you return to the top display.  However, depending upon your
              screen width and the order of your fields, this sort field may not  be  dis-
              playable.

              This  interactive  command can be a convenient way to simply verify the cur-
              rent sort field, when running top with column highlighting turned Off.

         ?R? :Reverse/Normal_Sort_Field_toggle
              Using this interactive command you can  alternate  between  high-to-low  and
              low-to-high sorts.

         Note: Field sorting uses internal values, not those in column display.  Thus, the
         TTY and WCHAN fields will violate strict ASCII collating sequence.

   3d. COLOR Mapping
       When you issue the 'Z' interactive command, you will be presented with  a  separate
       screen.   That screen can be used to change the colors in just the ?current' window
       or in all four windows before returning to the top display.

       Available interactive commands
           4 upper case letters to select a target
           8 numbers to select a color
           normal toggles available
               'B'       :bold disable/enable
               'b'       :running tasks "bold"/reverse
               'z'       :color/mono
           other commands available
               'a'/'w'   :apply, then go to next/prior
               <Enter>   :apply and exit
               'q'       :abandon current changes and exit

       If your use 'a' or 'w' to cycle the targeted window,  you  will  have  applied  the
       color  scheme  that  was  displayed when you left that window.  You can, of course,
       easily return to any window and reapply different colors or turn  colors  Off  com-
       pletely with the 'z' toggle.

       The  Color  Mapping  screen  can  also be used to change the ?current' window/field
       group in either full-screen mode or alternate-display mode.  Whatever was  targeted
       when  'q' or <Enter> was pressed will be made current as you return to the top dis-
       play.


4. ALTERNATE-DISPLAY Mode
   4a. WINDOWS Overview
       Field Groups/Windows:
              In full-screen mode there is a  single  window  represented  by  the  entire
              screen.  That single window can still be changed to display 1 of 4 different
              field groups (see the 'G' interactive command, repeated below).  Each of the
              4 field groups has a unique separately configurable summary area and its own
              configurable task area.

              In alternate-display mode, those 4 underlying field groups can now  be  made
              visible simultaneously, or can be turned Off individually at your command.

              The  summary area will always exist, even if it's only the message line.  At
              any given time only one summary area can be displayed.   However,  depending
              on  your  commands,  there could be from zero to four separate task displays
              currently showing on the screen.

       Current Window:
              The ?current' window is the window associated with the summary area and  the
              window  to which task related commands are always directed.  Since in alter-
              nate-display mode you can toggle the task display Off, some  commands  might
              be restricted for the ?current' window.

              A  further  complication arises when you have toggled the first summary area
              line Off.  With the loss of the window name (the 'l' toggled  line),  you'll
              not easily know what window is the ?current' window.

   4b. COMMANDS for Windows
         ?-? and ?_? :Show/Hide_Window(s)_toggles
              The  '-' key turns the ?current' window's task display On and Off.  When On,
              that task area will show a minimum of the columns header you've  established
              with  the  'f'  and  'o' commands.  It will also reflect any other task area
              options/toggles you've applied yielding zero or more tasks.

              The '_' key does the same  for  all  task  displays.   In  other  words,  it
              switches  between  the  currently  visible task display(s) and any task dis-
              play(s) you had toggled Off.  If all 4 task displays are currently  visible,
              this  interactive  command  will  leave the summary area as the only display
              element.

       * ?=? and ?+? :Equalize_(re-balance)_Window(s)
              The '=' key forces the ?current' window's task display to  be  visible.   It
              also  reverses  any 'i' (idle tasks) and 'n' (max tasks) commands that might
              be active.

              The '+' key does the same for all windows.   The  four  task  displays  will
              reappear,  evenly balanced.  They will also have retained any customizations
              you had previously applied, except for the 'i' (idle  tasks)  and  'n'  (max
              tasks) commands.

       * ?A? :Alternate_Display_Mode_toggle
              This  command  will  switch  between  full-screen mode and alternate-display
              mode.

              The first time you issue this command, all four task displays will be shown.
              Thereafter  when  you  switch  modes,  you will see only the task display(s)
              you've chosen to make visible.

       * ?a? and ?w? :Next_Window_Forward/Backward
              This will change the ?current' window, which in turn changes the  window  to
              which  commands  are  directed.  These keys act in a circular fashion so you
              can reach any desired ?current' window using either key.

              Assuming the window name is visible (you have not toggled 'l' Off), whenever
              the  ?current'  window  name loses its emphasis/color, that's a reminder the
              task display is Off and many commands will be restricted.

       * ?G? :Choose_Another_Window/Field_Group
              You will be prompted to enter a number between 1 and 4 designating the  win-
              dow/field group which should be made the ?current' window.

              In  full-screen  mode, this command is necessary to alter the ?current' win-
              dow.  In alternate-display mode, it is simply a less convenient  alternative
              to the 'a' and 'w' commands.

         ?g? :Change_Window/Field_Group_Name
              You  will  be prompted for a new name to be applied to the ?current' window.
              It does not require that the window name be visible (the 'l'  toggle  to  be
              On).

       *  The  interactive  commands  shown  with an asterisk ('*') have use beyond alter-
          nate-display mode.
              ?=', 'A', 'G'  are always available
              ?a', 'w'       act the same when color mapping


5. FILES
   5a. SYSTEM Configuration File
       The presence of this file will influence which version  of  the  'help'  screen  is
       shown to an ordinary user.  More importantly, it will limit what ordinary users are
       allowed to do when top is running.  They will not be able to  issue  the  following
       commands.
          k         Kill a task
          r         Renice a task
          d or s    Change delay/sleep interval

       The  system configuration file is not created by top.  Rather, you create this file
       manually and place it in the /etc directory.  Its name must  be  'toprc'  and  must
       have no leading '.' (period).  It must have only two lines.

       Here is an example of the contents of /etc/toprc:
          s         # line 1: 'secure' mode switch
          5.0       # line 2: 'delay'  interval in seconds

   5b. PERSONAL Configuration File
       This  file  is written as '$HOME/.your-name-4-top' + 'rc'.  Use the 'W' interactive
       command to create it or update it.

       Here is the general layout:
          global    # line 1: the program name/alias notation
            "       # line 2: id,altscr,irixps,delay,curwin
          per ea    # line a: winname,fieldscur
          window    # line b: winflags,sortindx,maxtasks
            "       # line c: summclr,msgsclr,headclr,taskclr

       If the $HOME variable is not present, top will try to write the personal configura-
       tion file to the current directory, subject to permissions.


6. STUPID TRICKS Sampler
       Many  of these 'tricks' work best when you give top a scheduling boost.  So plan on
       starting him with a nice value of -10, assuming you've got the authority.

   6a. Kernel Magic
       For these stupid tricks, top needs full-screen mode.

       -*-  The user interface, through prompts and help, intentionally implies  that  the
            delay  interval is limited to tenths of a second.  However, you're free to set
            any desired delay.  If you want to see Linux at his  scheduling  best,  try  a
            delay of .09 seconds or less.

            For  this  experiment, under x-windows open an xterm and maximize it.  Then do
            the following:
              . provide a scheduling boost and tiny delay via:
                  nice -n -10 top -d.09
              . keep sorted column highlighting Off to minimize
                path length
              . turn On reverse row highlighting for emphasis
              . try various sort columns (TIME/MEM work well),
                and normal or reverse sorts to bring the most
                active processes into view

            What you'll see is a very busy Linux doing what he's always done for you,  but
            there was no program available to illustrate this.

       -*-  Under  an xterm using 'white-on-black' colors, try setting top's task color to
            black and be sure that task highlighting is set to bold,  not  reverse.   Then
            set the delay interval to around .3 seconds.

            After  bringing  the  most active processes into view, what you'll see are the
            ghostly images of just the currently running tasks.

       -*-  Delete the existing rcfile, or create a new symlink.  Start this  new  version
            then  type  'T' (a secret key, see topic 3c. TASK Area Commands, Sorting) fol-
            lowed by 'W' and 'q'.  Finally, restart the program with -d0 (zero delay).

            Your display will be refreshed at three times the rate of the  former  top,  a
            300% speed advantage.  As top climbs the TIME ladder, be as patient as you can
            while speculating on whether or not top will ever reach the top.

   6b. Bouncing Windows
       For these stupid tricks, top needs alternate-display mode.

       -*-  With 3 or 4 task displays visible, pick any window other  than  the  last  and
            turn  idle  processes Off.  Depending on where you applied 'i', sometimes sev-
            eral task displays are bouncing and sometimes it's like an accordion,  as  top
            tries his best to allocate space.

       -*-  Set  each window's summary lines differently: one with no memory; another with
            no states; maybe one with nothing at all, just the message  line.   Then  hold
            down  'a'  or  'w' and watch a variation on bouncing windows  --  hopping win-
            dows.

       -*-  Display all 4 windows and for each,  in  turn,  set  idle  processes  to  Off.
            You've just entered the "extreme bounce" zone.

   6c. The Big Bird Window
       This stupid trick also requires alternate-display mode.

       -*-  Display all 4 windows and make sure that 1:Def is the ?current' window.  Then,
            keep increasing window size until the all the other task displays are  "pushed
            out of the nest".

            When they've all been displaced, toggle between all visible/invisible windows.
            Then ponder this:
               is top fibbing or telling honestly your imposed truth?


7. BUGS
       Send bug reports to:
          Albert D. Cahalan, <albert AT users.net>

       The top command calculates Cpu(s) by looking at  the  change  in  CPU  time  values
       between samples. When you first run it, it has no previous sample to compare to, so
       these initial values are the percentages since boot. It means you need at least two
       loops  or  you  have to ignore summary output from the first loop.  This is problem
       for example for batch mode. There is a possible workaround if you define  the  CPU-
       LOOP=1  environment variable. The top command will be run one extra hidden loop for
       CPU data before standard output.

8. HISTORY Former top
       The  original  top  was  written  by  Roger  Binns,  based  on  Branko  Lankester's
       <lankeste AT fwi.nl> ps program.

       Robert  Nation  <nation AT rocket.com>  adapted  it for the proc file
       system.

       Helmut Geyer <Helmut.Geyer AT iwr.de> added  support  for  configurable
       fields.

       Plus many other individuals contributed over the years.


9. AUTHOR
       This entirely new and enhanced replacement was written by:
          Jim / James C. Warner, <warnerjc AT worldnet.net>

       With invaluable help from:
          Albert D. Cahalan, <albert AT users.net>
          Craig Small, <csmall AT small.au>


10. SEE ALSO
       free(1), ps(1), uptime(1), atop(1), slabtop(1), vmstat(8), w(1).






Linux                           September 2002                          TOP(1)

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