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TOP(1) manual page
Table of Contents
top - display Linux tasks
-hv | -bcisS -d delay -n iterations -p pid [, pid ...]
The traditional switches
’-’ and whitespace are optional.
The 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 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 M encompassing every
aspect of its operation. And while is referred to throughout this document,
you are free to name the program anything you wish. That new name, possibly
an alias, will then be reflected on ’s display and used when reading and
writing a .
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
When operating , 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 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 customize your .
the width of ’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.
The following startup defaults assume no , thus no user
customizations. Even so, items shown with an 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)
* ’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)
The command-line syntax for consists of:
-hv | -bcisS -d delay -n iterations
-p pid [,pid...]
The typically mandatory switches (’-’) and even whitespace are
completely optional.
- -b : Batch mode operation
- Starts in ’Batch mode’, which
could be useful for sending output from to other programs or to a file.
In this mode, will not accept input and runs until the iterations limit
you’ve set with the ’-n’ or until killed.
- -c : Command line/Program name toggle
- Starts with the last remembered ’c’ state reversed. Thus, if was displaying
command lines, now that field will show program names, and visa versa.
’c’ 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 or the startup default. Later this can be changed
with the ’d’ or ’s’ s.
Fractional seconds are honored, but a negative number
is not allowed. In all cases, however, such changes are prohibited if is
running in ’Secure mode’, except for root (unless the ’s’ was used). For additional
information on ’Secure mode’ 5a. SYSTEM Configuration File.
- -h : Help
- Show
library version and the usage prompt, then quit.
- -i : Idle Processes toggle
- Starts with the last remembered ’i’ state reversed. When this toggle is ,
tasks that are idled or zombied will not be displayed.
- -n : Number of iterations
limit as: -n number
- Specifies the maximum number of iterations, or frames,
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 permitted.
This is a only. And should you wish to return
to normal operation, it is not necessary to quit and and restart M just
issue the ’=’ .
- -s : Secure mode operation
- Starts with secure mode forced,
even for root. This mode is far better controlled through the system (
5. FILES).
- -S : Cumulative time mode toggle
- Starts with the last remembered
’S’ state reversed. When ’Cumulative mode’ is , each process is listed with
the time that it and its dead children have used. ’S’ for additional information
regarding this mode.
- -v : Version
- Show library version and the usage prompt,
then quit.
Listed below
are ’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) .
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 3c. TASK Area Commands.
- a: PID M Process Id
- The task’s
unique process ID, which periodically wraps, though never restarting at
zero.
- b: PPID M Parent Process Pid
- The process ID of a task’s parent.
- c:
RUSER M Real User Name
- The real user name of the task’s owner.
- d: UID M
User Id
- The effective user ID of the task’s owner.
- e: USER M User Name
- The
effective user name of the task’s owner.
- f: GROUP M Group Name
- The effective
group name of the task’s owner.
- g: TTY M 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 M Priority
- The priority of the task.
- i: NI M 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 M Last used (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
may break this weak affinity and cause more processes to change s more
often (because of the extra demand for time).
- k: %CPU M usage
- The task’s
share of the elapsed time since the last screen update, expressed as a
percentage of total time. In a true SMP environment, if ’Irix mode’ is ,
will operate in ’Solaris mode’ where a task’s usage will be divided by the
total number of s. You toggle ’Irix/Solaris’ modes with the ’I’ .
- l: TIME M
Time
- Total time the task has used since it started. When ’Cumulative mode’
is , each process is listed with the time that it and its dead children
has used. You toggle ’Cumulative mode’ with ’S’, which is a and an . ’S’ for
additional information regarding this mode.
- m: TIME+ M Time, hundredths
- The same as ’TIME’, but reflecting more granularity through hundredths of
a second.
- n: %MEM M Memory usage (RES)
- A task’s currently used share of
available .
- o: VIRT M Virtual Image (kb)
- The total amount of used by the
task. It includes all code, data and shared libraries plus pages that have
been swapped out.
VIRT = SWAP + RES.
- p: SWAP M Swapped size (kb)
- The swapped
out portion of a task’s total image.
- q: RES M Resident size (kb)
- The non-swapped
a task has used.
RES = CODE + DATA.
- r: CODE M Code size (kb)
- The amount
of devoted to executable code, also known as the ’text resident set’ size
or TRS.
- s: DATA M Data+Stack size (kb)
- The amount of devoted to other
than executable code, also known as the ’data resident set’ size or DRS.
- t: SHR M Shared Mem size (kb)
- The amount of used by a task. It simply reflects
memory that could be potentially shared with other processes.
- u: nFLT M
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 M 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 M 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’ M 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 ’s delay interval and nice value.
- x: Command M 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 and an .
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.
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 M 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.
By displaying this
field, ’s own working set will be increased by over 700Kb. Your only means
of reducing that overhead will be to stop and restart .
- z: Flags M 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.
After pressing the s ’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 ’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 (screen width permitting). This will
also be indicated by a leading , 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 M the ’f’
- You toggle the display of a field by simply
pressing the corresponding letter.
- Order fields screen M the ’o’
- You move
a field to the left by pressing the corresponding upper case letter and
to the right with the lower case letter.
Listed
below is a brief index of commands within categories. Some commands appear
more than once M 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, 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
The global s are always available in both M and . However,
some of these s are not available when running in ’Secure mode’.
If you wish
to know in advance whether or not your 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
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 s. If is secured, that screen
will be abbreviated.
Typing ’h’ or ’?’ on that help screen will take you to
help for those s applicable to .
- ’=’ :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’ for a discussion of PID monitoring.
When
operating in this command has a slightly broader meaning.
- ’A’ :Alternate_Display_Mode_toggle
- This command will switch between M and . 4. ALTERNATE-DISPLAY Mode and the
’G’ for insight into s and field groups.
- ’B’ :Bold_Disable/Enable_toggle
- This
command will influence use of the ’bold’ terminfo capability and alters both
the and for the . While it is intended primarily for use with dumb terminals,
it can be applied anytime.
When this toggle is and 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 display
as the system and tty driver try to keep up with ’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 . You will soon grow comfortable
with these 4 windows, especially after experimenting with .
- ’I’ :Irix/Solaris_Mode_toggle
- When operating in ’Solaris mode’ (’I’ toggled ), a task’s usage will be divided
by the total number of s. 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 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 , 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 , or for all windows. For details regarding this 3d. COLOR Mapping.
- *
- The commands shown with an are not available in ’Secure mode’, nor will
they be shown on the level-1 help screen.
The
s are always available in both M and . They affect the beginning lines of
your display and will determine the position of messages and prompts.
These
commands always impact just the /field group. 4. ALTERNATE-DISPLAY Mode and
the ’G’ for insight into s and field groups.
- ’l’ :Toggle_Load_Average/Uptime
M On/Off
- This is also the line containing the program name (possibly an
alias) when operating in M or the name when operating in .
- ’m’ :Toggle_Memory/Swap_Usage
M On/Off
- This command affects two lines.
- ’t’ :Toggle_Task/Cpu_States M On/Off
- This command affects from 2 to many lines, depending on the state of the
’1’ toggle and whether or not is running under true SMP.
- ’1’ :Toggle_Single/Separate_Cpu_States
M 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 , the ’1’ toggle is and all information is gathered
in a single line. Otherwise, each is displayed separately as: ’Cpu0, Cpu1,
...’
If the entire has been toggled 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 M or the name when
in .
The s are always available in M.
The s are
never available in if the ’s has been toggled ( 4. ALTERNATE-DISPLAY Mode).
APPEARANCE of
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 .
- ’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 hopes that you always run with ’column
highlight’ , 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, 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 between your last used color scheme and the older form of black-on-white
or white-on-black. This command will alter both the and but does not affect
the state of the ’x’, ’y’ or ’b’ toggles.
CONTENT of
- ’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 s 2b. SELECTING and ORDERING
Columns.
- ’S’ :Cumulative_Time_Mode_toggle
- When ’Cumulative mode’ is , each
process is listed with the time that it and its dead children have used.
When , 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 s 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 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
- ’i’ :Idle_Processes_toggle
- Displays all tasks or just active tasks. When
this toggle is , idled or zombied processes will not be displayed.
If this
command is applied to the last when in , then it will not affect the window’s
size, as all prior s 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 , this
is the command that gives you precise control over the size of each currently
visible , except for the very last. It will not affect the last window’s
size, as all prior s will have already been painted.
If you wish to increase
the size of the last visible when in , simply decrease the size of the
(s) above it.
SORTING of
For compatibility, this supports most of the former sort keys. Since
this is primarily a service to former 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, suggests that you
temporarily turn on column highlighting using the ’x’ . That will help ensure
that the actual sort environment matches your intent.
The following s 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’ turned it
- ’<’ :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 s 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 when you return to the display. However,
depending upon your screen width and the order of your fields, this sort
field may not be displayable.
This can be a convenient way to simply verify
the current sort field, when running with column highlighting turned .
- ’R’ :Reverse/Normal_Sort_Field_toggle
- Using this you can alternate between
high-to-low and low-to-high sorts.
Field sorting uses internal values, not
those in column display. Thus, the TTY and WCHAN fields will violate strict
ASCII collating sequence.
When you issue the ’Z’ , you
will be presented with a separate screen. That screen can be used to change
the colors in just the or in all four windows before returning to the
display.
Available s 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 completely with the ’z’ toggle.
The Color Mapping screen can
also be used to change the /field group in either M or . Whatever was targeted
when ’q’ or <Enter> was pressed will be made current as you return to the
display.
- Field Groups/Windows:
In M 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 (
’G’ , repeated below). Each of the 4 field groups has a unique separately
configurable and its own configurable .
In , those 4 underlying field
groups can now be made visible simultaneously, or can be turned individually
at your command.
The will always exist, even if it’s only the message line.
At any given time only one can be displayed. However, depending on your
commands, there could be from zero to four separate s currently showing
on the screen.
- Current Window:
The is the window associated with the and the window to which task related
commands are always directed. Since in you can toggle the , some commands
might be restricted for the .
A further complication arises when you have
toggled the first line . With the loss of the window name (the ’l’ toggled
line), you’ll not easily know what window is the .
- ’-’
and ’_’ :Show/Hide_Window(s)_toggles
- The ’-’ key turns the ’s and . When , that
will show a minimum of the columns header you’ve established with the ’f’
and ’o’ commands. It will also reflect any other options/toggles you’ve applied
yielding zero or more tasks.
The ’_’ key does the same for all s. In other
words, it switches between the currently visible (s) and any (s) you had
toggled . If all 4 s are currently visible, this will leave the as the
only display element.
- * ’=’ and ’+’ :Equalize_(re-balance)_Window(s)
- The ’=’ key
forces the ’s 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 s 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 M and .
The first time you issue this command, all
four s will be shown. Thereafter when you switch modes, you will see only
the (s) you’ve chosen to make visible.
- * ’a’ and ’w’ :Next_Window_Forward/Backward
- This will change the , which in turn changes the window to which commands
are directed. These keys act in a circular fashion so you can reach any
desired using either key.
Assuming the window name is visible (you have
not toggled ’l’ ), whenever the name loses its emphasis/color, that’s a reminder
the is 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 .
In M, this command is necessary
to alter the . In , 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 . It does not require that the window
name be visible (the ’l’ toggle to be ).
- *
- The s shown with an have use beyond
. ’=’, ’A’, ’G’ are always available
’a’, ’w’ act the same when color mapping
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
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 is not created by . 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
This file is written as ’$HOME/.your-name-4-top’
+ ’rc’. Use the ’W’ 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, will try to write the personal
to the current directory, subject to permissions.
Many of these ’tricks’ work best when you give a scheduling boost. So plan
on starting him with a nice value of -10, assuming you’ve got the authority.
For these stupid tricks, needs M.
- -*-
- 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 to minimize
path length
. turn 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 ’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, 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 , a 300% speed
advantage. As climbs the TIME ladder, be as patient as you can while speculating
on whether or not will ever reach the .
For these
stupid tricks, needs .
- -*-
- With 3 or 4 s visible, pick any window other
than the last and turn idle processes . Depending on where you applied ’i’,
sometimes several s are bouncing and sometimes it’s like an accordion, as
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 M hopping windows.
- -*-
- Display all 4 windows and for each, in turn,
set idle processes to . You’ve just entered the "extreme bounce" zone.
This stupid trick also requires .
- -*-
- Display all 4 windows
and make sure that 1:Def is the . Then, keep increasing window size until
the all the other s are "pushed out of the nest".
When they’ve all been
displaced, toggle between all visible/invisible windows. Then ponder this:
is fibbing or telling honestly your imposed truth?
Send bug reports to: Albert D. Cahalan, <albert@users.sf.net>
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.
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>
free(1)
, ps(1)
, uptime(1)
, atop(1)
, slabtop(1)
, vmstat(8)
,
w(1)
.
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