top | Début | Suivant | Sommaire | Préc.page.lue | Accueil |
NAME | Début | Précédent | Suivant | Sommaire | Préc.page.lue | Accueil |
SYNOPSIS | Début | Précédent | Suivant | Sommaire | Préc.page.lue | Accueil |
The traditional switches '-' and whitespace are optional.
DESCRIPTION | Début | Précédent | Suivant | Sommaire | Préc.page.lue | Accueil |
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, possibly an alias, will then be reflected on top's display and used when reading and writing a configuration file.
OVERVIEW | Début | Précédent | Suivant | Sommaire | Préc.page.lue | Accueil |
Documentation | Début | Précédent | Suivant | Sommaire | Préc.page.lue | Accueil |
Operation | Début | Précédent | Suivant | Sommaire | Préc.page.lue | Accueil |
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.
Task_Area: Tasks running (or ready to run) will be highlighted, and bold is only one way of emphasizing such processes.
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 | Début | Précédent | Suivant | Sommaire | Préc.page.lue | Accueil |
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 | Début | Précédent | Suivant | Sommaire | Préc.page.lue | Accueil |
-hv | -bcHisS -d delay -n iterations -p pid [,pid...]
The typically mandatory switches ('-') and even whitespace are completely optional.
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.
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.
2. FIELDS / Columns | Début | Précédent | Suivant | Sommaire | Préc.page.lue | Accueil |
2a. DESCRIPTIONS of Fields | Début | Précédent | Suivant | Sommaire | Préc.page.lue | Accueil |
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.
VIRT = SWAP + RES.
RES = CODE + DATA.
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.
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.
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.
2b. SELECTING and ORDERING Columns | Début | Précédent | Suivant | Sommaire | Préc.page.lue | Accueil |
Here is a sample fields string from one of top's four windows/field groups and an explanation of the conventions used:
2c. SUMMARY Area Fields | Début | Précédent | Suivant | Sommaire | Préc.page.lue | Accueil |
3. INTERACTIVE Commands | Début | Précédent | Suivant | Sommaire | Préc.page.lue | Accueil |
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 | Début | Précédent | Suivant | Sommaire | Préc.page.lue | Accueil |
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.
Use either of these keys if you have a large delay interval and wish to see current status,
Typing 'h' or '?' on that help screen will take you to help for those interactive commands applicable to alternate-display mode.
When operating in alternate-display mode this command has a slightly broader meaning.
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.
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 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.
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
3b. SUMMARY Area Commands | Début | Précédent | Suivant | Sommaire | Préc.page.lue | Accueil |
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.
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 | Début | Précédent | Suivant | Sommaire | Préc.page.lue | Accueil |
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.
If you forget which field is being sorted this command can serve as a quick visual reminder.
Use of this provision provides important insight into your system's health. The only costs will be a few additional tty escape sequences.
CONTENT of task window
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.
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
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.
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
The following interactive commands will always be honored whether or not the current sort field is visible.
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.
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 | Début | Précédent | Suivant | Sommaire | Préc.page.lue | Accueil |
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 | Début | Précédent | Suivant | Sommaire | Préc.page.lue | Accueil |
4a. WINDOWS Overview | Début | Précédent | Suivant | Sommaire | Préc.page.lue | Accueil |
In alternate-display mode, those 4 underlying field groups can now be made visible simultaneously, or can be turned Off individually at your command.
The summary area will always exist, even if it's only the message line. At any given time only one summary area can be displayed. However, depending on your commands, there could be from zero to four separate task displays currently showing on the screen.
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 | Début | Précédent | Suivant | Sommaire | Préc.page.lue | Accueil |
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 displays are currently visible, this interactive command will leave the summary area as the only display element.
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.
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.
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.
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.
5. FILES | Début | Précédent | Suivant | Sommaire | Préc.page.lue | Accueil |
5a. SYSTEM Configuration File | Début | Précédent | Suivant | Sommaire | Préc.page.lue | Accueil |
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 | Début | Précédent | Suivant | Sommaire | Préc.page.lue | Accueil |
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 | Début | Précédent | Suivant | Sommaire | Préc.page.lue | Accueil |
6a. Kernel Magic | Début | Précédent | Suivant | Sommaire | Préc.page.lue | Accueil |
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.
After bringing the most active processes into view, what you'll see are the ghostly images of just the currently running tasks.
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 | Début | Précédent | Suivant | Sommaire | Préc.page.lue | Accueil |
6c. The Big Bird Window | Début | Précédent | Suivant | Sommaire | Préc.page.lue | Accueil |
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 | Début | Précédent | Suivant | Sommaire | Préc.page.lue | Accueil |
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 | Début | Précédent | Suivant | Sommaire | Préc.page.lue | Accueil |
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 | Début | Précédent | Suivant | Sommaire | Préc.page.lue | Accueil |
With invaluable help from:
Albert D. Cahalan, <albert@users.sf.net>
Craig Small, <csmall@small.dropbear.id.au>
10. SEE ALSO | Début | Précédent | Suivant | Sommaire | Préc.page.lue | Accueil |
Sommaire | Début | Suivant | Sommaire | Préc.page.lue | Accueil |
Table des mots clés | Début | Suivant | Sommaire | Préc.page.lue | Accueil |
Content/Labels | Operation |
Current Window: | 4a. WINDOWS Overview |
Field Groups/Windows: | 4a. WINDOWS Overview |
Fields select screen -- the 'f' interactive command | 2b. SELECTING and ORDERING Columns |
Highlighting | Operation |
Order fields screen -- the 'o' interactive command | 2b. SELECTING and ORDERING Columns |