Man Pages

top(1) - phpMan top(1) - phpMan

Command: man perldoc info search(apropos)  


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 display system summary informa-
       tion 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   --   encompassing  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 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 cus-
          tomize 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 | -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 displaying  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  con-
            figuration  file  or  the startup default.  Later this can be changed with the 'd' or 's' interactive com-
            mands.

            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 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 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 summary.


       -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 neces-
            sary 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.


       -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 letter 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 information
          regarding this mode.


       m: TIME+  --  CPU Time, hundredths
          The same as 'TIME', but reflecting more granularity through hundredths 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 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 writ-
          ten 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 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 conven-
       tions 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.  How-
       ever, 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 sys-
       tem 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 alternate-display mode.  See topic 4. ALTER-
              NATE-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)  con-
              tinuous  updates,  with an unsatisfactory display 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 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 num-
              ber 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  dis-
              played. 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 dis-
              played. 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 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' 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. 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 displayed.  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 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 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 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.  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
              prefer.

              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  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  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 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 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.  However, 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 verify the current 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  dis-
       play.

       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 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 con-
              figurable 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 sum-
              mary area can be displayed.  However, depending on your commands, there could be from zero to four sepa-
              rate 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 vis-
              ible  task display(s) and any task display(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 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 ?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 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 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 configuration 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 avail-
            able 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) 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 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 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/invisible windows.  Then ponder this:
               is top fibbing or telling honestly your imposed truth?


7. BUGS
       Send bug reports to:
          Albert D. Cahalan, <albertATusers.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 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 <lankesteATfwi.nl> ps program.

       Robert Nation <nationATrocket.com> adapted it for the proc file system.

       Helmut Geyer <Helmut.GeyerATiwr.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, <warnerjcATworldnet.net>

       With invaluable help from:
          Albert D. Cahalan, <albertATusers.net>
          Craig Small, <csmallATsmall.au>


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






Linux                           September 2002                          TOP(1)