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top command man page

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

NAME
       top - display Linux tasks

SYNOPSIS
       top -hv | -bcHisS -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 display system summary information as well as a  list  of tasks
       currently  being managed by the Linux kernel.  The types of system sum-
       mary 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 manip-
       ulation as well as a much more extensive interface for personal config-
       uration --  encompassing every aspect of its operation. And while top
       is  referred to throughout this document, you are free to name the pro-
       gram anything you wish. That new name, possibly an alias, will then be
       reflected on top’s display and used when reading and writing a configu-
       ration 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 tradi-
       tional 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  differ-
       ences when compared to the former top.


       Highlighting
 Summary_Area: There is no highlighting for load/uptime and only val-
 ues are highlighted 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 customizations.  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 | -bcHisSM -d delay -n iterations -p pid [,pid...]

       The typically mandatory switches (’-’) and  even whitespace  are  com-
       pletely optional.


       -b : Batch mode operation
   Starts top in ’Batch mode’, which could be useful for sending out-
   put 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 displaying command lines, now that field will show program
   names, and visa versa.  See the ’c’ interactive command for addi-
   tional information.


       -d : Delay time interval as:  -d ss.tt (seconds.tenths)
   Specifies the delay between screen updates, and overrides the cor-
   responding 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. Other-
   wise, top displays a summation 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 dis-
   played.


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


       -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.


       -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  permit-
   ted.

   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 information regarding this mode.


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


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


2. FIELDS / Columns
   2a. DESCRIPTIONS of Fields
       Listed  below  are  top’s available fields.  They are always associated
       with the letter shown, regardless of the position you may  have estab-
       lished 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 pri-
 ority,  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 envi-
 ronment this will likely change frequently since the kernel inten-
 tionally  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  information  regarding  this
 mode.


       m: TIME+ --  CPU Time, hundredths
 The  same  as ’TIME’,  but reflecting more granularity through hun-
 dredths of a second.


       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 vari-
 able and  the VIRT will be calculated from the /proc/#/state VmSize
 field.)

 VIRT = SWAP + RES.


       p: SWAP --  Swapped size (kb)
 The swapped out portion of a task’s total virtual memory image.


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

 RES = CODE + DATA.


       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 mem-
 ory 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  program. You toggle between command line and name with
 ’c’, which is both a command-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  pro-
 gram 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 let-
 ters 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 correspond-
 ing 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.


3. INTERACTIVE Commands
       Listed below is a brief index of commands within categories.  Some com-
       mands 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 interactive 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 alter-
     nate-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  capabil-
     ity and alters both the summary area and task area for the ´cur-
     rent’ 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 empha-
     sis, 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 display as the system and tty driver try to  keep
     up  with top’s  demands.  The delay value is inversely propor-
     tional 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 designat-
     ing the window/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 issu-
     ing 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.  How-
     ever, 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 negative 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’  win-
     dow 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, depend-
     ing 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  mas-
     sively-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. Other-
     wise, 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 alter-
       nate-display mode if the ´current’ window’s task display has been  tog-
       gled Off (see topic 4. ALTERNATE-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  dis-
     played.  Further, 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  sys-
     tem’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 currently 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  informa-
     tion  on these interactive commands see topic 2b. SELECTING and
     ORDERING Columns.

´H´ :Threads_toggle
     When this toggle is On, all  individual  threads will  be  dis-
     played.  Otherwise, 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 sharing the same sort field but
     with  different ’S’ states and see which representation you pre-
     fer.

     After issuing this command, you’ll be informed of the new state
     of  this toggle. 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-display mode, then  it  will not affect the window’s
     size, as all prior task displays 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 precise control over the size of each currently visi-
     ble  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 temporarily 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 cur-
rent  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 current 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.  How-
     ever, depending upon your screen width and  the  order  of  your
     fields, this sort field may not be displayable.

     This  interactive command can be a convenient way to simply ver-
     ify the current sort field, when running top with column high-
     lighting 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  dis-
play. Thus, the TTY and WCHAN fields will violate strict ASCII col-
lating 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 completely 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 display.


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  dis-
     play 1 of 4 different field groups (see the ’G’ interactive com-
     mand, 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 indi-
     vidually at your command.

     The summary area will always exist, even if it’s only  the  mes-
     sage  line.  At any given time only one summary area can be dis-
     played.  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 alternate-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 display(s) you had toggled Off.  If all 4 task dis-
     plays 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 dis-
     plays 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 alter-
     nate-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 empha-
     sis/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 designat-
     ing the window/field group which should be  made the  ´current’
     window.

     In  full-screen  mode,  this  command  is necessary to alter the
     ´current’ window. 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 ´cur-
     rent’ window.  It does not require that the window name be visi-
     ble (the ’l’ toggle to be On).

       *  The  interactive  commands  shown  with  an  asterisk (’*’) have use
 beyond alternate-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 cre-
       ate 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 per-
       sonal configuration file to the current directory, subject  to  permis-
       sions.


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 sec-
   onds.

   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) followed by ’W’ and ’q’.  Finally, restart the
   program with -d0 (zero delay).

   Your display will be refreshed at three times the rate of the for-
   mer 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  several  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 windows.

       -*-  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/invis-
   ible windows.  Then ponder this:
      is top fibbing or telling honestly your imposed truth?


7. BUGS
       Send bug reports to:
 Albert D. Cahalan, <albert@users.sf.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  sam-
       ple  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  sum-
       mary output from the first loop. This is problem for example for batch
       mode. There is a possible  workaround  if  you define the  CPULOOP=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@fwi.uva.nl> ps program.

       Robert  Nation  <nation@rocket.sanders.lockheed.com> adapted it for the
       proc file system.

       Helmut Geyer  <Helmut.Geyer@iwr.uni-heidelberg.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@worldnet.att.net>

       With invaluable help from:
 Albert D. Cahalan, <albert@users.sf.net>
 Craig Small, <csmall@small.dropbear.id.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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