.TH PS 1 "September 14, 2004"
.SH NAME
ps \- Display processes
.SH SYNOPSIS
ps [ DRSTCZEUIMA ]
.SH DESCRIPTION
The
.B ps
command displays the status of all processes in the desired state.
This command does not take any locks (all cpus should be frozen while
kdb is running) so it can safely be used to debug lock problems with
the process table.
.P
Without any parameters, \fBps\fP displays all the interesting
processes, excluding idle tasks and sleeping system daemons.
If a parameter is specified, it is a single string consisting of the
letters D, R, S, T, C, Z, E, U, I and M, in any order.
Each letter selects processes in a specific state, when multiple
letters are specified, a process will be displayed if it is in any of
the specified states.
The states are\ :-
.P
.DS
.TS
box, center;
l | l
l | l.
D	Uninterruptible sleep
R	Running
S	Interruptible sleep
T	Stopped
C	Traced
Z	Zombie
E	Dead
U	Unrunnable
I	Idle task
M	Sleeping system daemon
A	All
.TE
.DE
.P
For state R (running), the process may not be on a cpu at the moment,
but it is ready to run.
The header line above the backtrace contains '1' in the fourth field if
the process is actually on a cpu.
.P
The idle task is run on each cpu when there is no work for that cpu to do.
Unless the idle task is servicing an interrupt, there is no point in
printing the idle task.
An idle task that is not servicing a interrupt is marked as state I,
while servicing an interrupt it is in state R.
By default, idle tasks are not printed, use \fBps\ I\fR to print them.
If the idle tasks are not being printed, the start of the \fBps\R
output contains a list of which cpus are idle.
.P
Each cpu has one or more system daemons to handle per cpu work such as
soft irqs.
A system daemon (idenified by a NULL mm pointer) that is sleeping is
marked as state M.
These processes rarely have any useful data and generate a lot of
output on large machines, so sleeping system daemons are not printed by
default.
Use \fBps\ M\fR to print them.
.P
At the start of the \fBps\fR output is a line giving the cpu status,
see the kdb \fBcpu\fR command.
.SH LIMITATIONS
None.
.SH ENVIRONMENT
.TP 8
PS
This environment variable (default=DRSTCZEU) is used when \fBps\fR
is issued with no parameters.

.SH SMP CONSIDERATIONS
None.
.SH EXAMPLES
.TP 8
\fBps\fR
displays the useful tasks, suppressing idle tasks and sleeping
system daemons.

.TP 8
\fBps\ RD\fR
displays only tasks that are running or are in an uninterruptible
sleep.

.TP 8
\fBps\ DRSTCZEUIM\fR
displays all tasks.

.TP 8
\fBps\ A\fR
displays all tasks.
This is easier than remembering DRSTCZEUIM.