mtop(1)

NAME

mtop - display multicomputer top CPU processes

SYNOPSIS

mtop [-] [d delay] [q] [c] [S] [s] [i]

DESCRIPTION

mtop provides an ongoing look at processor activity in real time. It displays a listing of the most CPU-intensive tasks on the system, and can provide an interactive interface for manipulating processes. It can sort the tasks by CPU usage, memory usage and runtime. mtop can be better configured than the standard top from the procps suite. Most features can either be selected by an interactive command or by specifying the feature in the personal or system-wide configuration file. See below for more information.

COMMAND-LINE OPTIONS

d

Specifies the delay between screen updates. You can change this with the s interactive command.

q

This causes mtop to refresh without any delay. If the caller has superuser priviledges, mtop runs with the highest possible priority.

S

Specifies cumulative mode, where each process is listed with the CPU time that it as well as its dead children has spent. This is like the -S flag to ps(1). See the discussion below of the S interactive command.

s

Tells mtop to run in secure mode. This disables the potentially dangerous of the interactive commands (see below). A secure mtop is a nifty thing to leave running on a spare terminal.

i

Start mtop ignoring any idle or zombie processes. See the interactive command i below.

c

display command line instead of the command name only. The default behaviour has been changed as this seems to be more useful.

FIELD DESCRIPTIONS

mtop displays a variety of information about the processor state. The display is updated every 5 seconds by default, but you can change that with the d command-line option or the s interactive command.

uptime

This line displays the time the system has been up, and the three load averages for the system. The load averages are the average number of process ready to run during the last 1, 5 and 15 minutes. This line is just like the output of uptime(1). The uptime display may be toggled by the interactive l command.

processes

The total number of processes running at the time of the last update. This is also broken down into the number of tasks which are running, sleeping, stopped, or undead. The processes and states display may be toggled by the t interactive command.

CPU states

Shows the percentage of CPU time in user mode, system mode, niced tasks, and idle. (Niced tasks are only those whose nice value is negative.) Time spent in niced tasks will also be counted in system and user time, so the total will be more than 100%. The processes and states display may be toggled by the t interactive command.

Mem

Statistics on memory usage, including total available memory, free memory, used memory, shared memory, and memory used for buffers. The display of memory information may be toggled by the m interactive command.

Swap

Statistics on swap space, including total swap space, available swap space, and used swap space. This and Mem are just like the output of free(1).

PID

The process ID of each task.

PPID

The parent process ID each task.

UID

The user ID of the task's owner.

USER

The user name of the task's owner.

PRI

The priority of the task.

NI

The nice value of the task. Negative nice values are lower priority.

SIZE

The size of the task's code plus data plus stack space, in kilobytes, is shown here.

TSIZE

The code size of the task. This gives strange values for kernel processes and is broken for ELF processes.

DSIZE

Data + Stack size. This is broken for ELF processes.

TRS

Text resident size.

SWAP

Size of the swapped out part of the task.

D

Size of pages marked dirty.

N#

The Mosix Node Number where the process is running. 0 stand for the local node.

RSS

The total amount of physical memory used by the task, in kilobytes, is shown here. For ELF processes used library pages are counted here, for a.out processes not.

SHARE

The amount of shared memory used by the task is shown in this column.

STAT

The state of the task is shown here. The state is either S for sleeping, D for uninterruptible sleep, R for running, Z for zombies, or T for stopped or traced. These staes are modified by trailing < for a process with negative nice value, N for a process with positive nice value, W for a swapped out process (this does not work correctly for kernel processes).

WCHAN

depending on the availablity of either /boot/psdatabase or the kernel link map /boot/System.map this shows the address or the name of the kernel function the task currently is sleeping in.

TIME

Total CPU time the task has used since it started. If cumulative mode is on, this also includes the CPU time used by the process's children which have died. You can set cumulative mode with the S command line option or toggle it with the interactive command S. The header line will then be changed to CTIME.

%CPU

The task's share of the CPU time since the last screen update, expressed as a percentage of total CPU time.

%MEM

The task's share of the physical memory.

COMMAND

The task's command name, which will be truncated if it is too long to be displayed on one line. Tasks in memory will have a full command line, but swapped-out tasks will only have the name of the program in parentheses (for example, "(getty)").

A , WP

these fields from the kmem mtop are not supported.

INTERACTIVE COMMANDS

Several single-key commands are recognized while mtop is running. Some are disabled if the s option has been given on the command line.

space

Immediately updates the display.

^L

Erases and redraws the screen.

h or ?

Displays a help screen giving a brief summary of commands, and the status of secure and cumulative modes.

k

Kill a process. You will be prompted for the PID of the task, and the signal to send to it. For a normal kill, send signal 15. For a sure, but rather abrupt, kill, send signal 9. The default signal, as with kill(1), is 15, SIGTERM. This command is not available in secure mode.

i

Ignore idle and zombie processes. This is a toggle switch.

n or #

Change the number of processes to show. You will be prompted to enter the number. This overrides automatic determination of the number of processes to show, which is based on window size measurement. If 0 is specified, then mtop will show as many processes as will fit on the screen; this is the default.

q

Quit.

r

Re-nice a process. You will be prompted for the PID of the task, and the value to nice it to. Entering a positve value will cause a process to be niced to negative values, and lose priority. If root is running mtop, a negative value can be entered, causing a process to get a higher than normal priority. The default renice value is 10. This command is not available in secure mode.

S

This toggles cumulative mode, the equivalent of mps -S, i.e., that CPU times will include a process's defunct children. For some programs, such as compilers, which work by forking into many seperate tasks, normal mode will make them appear less demanding than they actually are. For others, however, such as shells and init, this behavior is correct. In any case, try cumulative mode for an alternative view of CPU use.

s

Change the delay between updates. You will be prompted to enter the delay time, in seconds, between updates. Fractional values are recognized down to microseconds. Entering 0 causes continuous updates. The default value is 5 seconds. Note that low values cause nearly unreadably fast displays, and greatly raise the load. This command is not available in secure mode.

f or F

Add fields to display or remove fields from the display. See below for more information.

o or O

Change order of displayed fields. See below for more information.

l

toggle display of load average and uptime information.

m

toggle display of memory information.

t

toggle display of processes and CPU states information.

c

toggle display of command name or full command line.

M

sort tasks by resident memory usage.

P

sort tasks by CPU usage (default).

T

sort tasks by time / cumulative time.

W

Write current setup to ~/.mtoprc. This is the recommended way to write a mtop configuration file.

g

migrate a process to a given node number. You must give the PID and the Node where it must be execute.

a

automatic migration. It migrates all processes that CPU charge exceed a given limit to a given node number.

N

sort task by Mosix Node Number.

The Field and Order Screens

After pressing f, F, o or O you will be shown a screen specifying the field order on the mtop line and short descriptions of the field contents. The field order string uses the following syntax: If the letter in the filed string corresponding to a field is upper case, the field will be displayed. This is furthermore indicated by an asterisk in front of the field description. The order of the fields corresponds to the order of the letters in the string.
From the field select screen you can toggle the display of a field by pressing the corresponding letter.
From the order screen you may move a field to the left by pressing the corresponding upper case letter resp. to the right by pressing the lower case one.

Configuration Files

Top reads it's default configuration from two files, /etc/mtoprc and ~/.mtoprc. The global configuration file may be used to restrict the usage of mtop to the secure mode for non-priviledged users. If this is desired, the file should contain a 's' to specify secure mode and a digit d (2<=d<=9) for the default delay (in seconds) on a single line. The personal configuration file contains two lines. The first line contains lower and upper letters to specify which fields in what order are to be displayed. The letters correspond to the letters in the Fields or Order screens from top. As this is not very instructive, it is recommended to select fields and order in a running top process and to save this using the W interactive command. The second line is more interesting (and important). It contains information on the other options. Most important, if you have saved a configuration in secure mode, you will not get an insecure mtop without removing the lower 's' from the second line of your ~/.mtoprc. A digit specifies the delay time between updates, a capital 'S' cumulative mode, a lower 'i' no-idle mode. As in interactive mode, a lower 'm', 'l', and 't' suppresses the display of memory, uptime resp. process and CPU state information. Currently changing the default sorting order (by CPU usage) is not supported.

NOTES

This proc-based mtop works by reading the files in the proc filesystem, mounted on /proc. If /proc is not mounted, mtop will not work.

%CPU shows the cputime/realtime percentage in the period of time between updates. For the first update, a short delay is used, and mtop itself dominates the CPU usage. After that, mtop will drop back, and a more reliable estimate of CPU usage is available.

The SIZE and RSS fields don't count the page tables and the task_struct of a process; this is at least 12K of memory that is always resident. SIZE is the virtual size of the process (code+data+stack).

Keep in mind that a process must die for its time to be recorded on its parent by cumulative mode. Perhaps more useful behavior would be to follow each process upwards, adding time, but that would be more expensive, possibly prohibitively so. In any case, that would make mtop's behavior incompatible with mps.

FILES

/etc/mtoprc The global configuration file. ~/.mtoprc The personal configuration file.

SEE ALSO

ps(1), mps(1), free(1), uptime(1), kill(1), renice(1).

BUGS

If the window is less than about 70x7, mtop will not format information correctly.
Many fields still have problems with ELF processes.
the help screens are not yet optimized for windows with less than 25 lines.

After a long time, mtop will not display any task, but processes are still running.

AUTHOR

top was originally written by Roger Binns, based on Branko Lankester's <[email protected]> ps program. Robert Nation <[email protected]> re-wrote it significantly to use the proc filesystem, based on Michael K. Johnson's <[email protected]> proc-based ps program. Michael Shields <[email protected]> made many changes, including secure and cumulative modes and a general cleanup.

Helmut Geyer <[email protected]> Heavily changed it to include support for configurable fields and other new options, and did further cleanup and use of the new readproc interface.

Michael K. Johnson <[email protected]> is now the maintainer.

mtop was written by Mathieu Cousin <[email protected]>. He patch the top source code to give informations on the location of processes on a mosix cluster. He is the current maintainer of this modified version.

Please send bug reports to <[email protected]>