PID -- Process Id:
The task's unique process ID, which periodically wraps, though never restarting at zero.
PPID -- Parent Process Pid:
The process ID of a task's parent.
RUSER -- Real User Name:
The real user name of the task's owner.
UID -- User Id:
The effective user ID of the task's owner.
USER -- User Name:
The effective user name of the task's owner.
GROUP -- Group Name:
The effective group name of the task's owner.
TTY -- Controlling Tty:
The name of the controlling terminal. This is usually the device (serial port, pty, etc.) from which the process was
which it uses for input or output. However, a task need not be associated with a terminal, in which case you'll see '?' displayed.
PR -- Priority:
The priority of the task.
NI -- Nice value:
The nice value of the task. A negative nice value means higher priority, whereas a positive nice value means lower priority.
this field simply means priority will not be adjusted in determining a task's dispatchability.
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
tionally uses weak affinity. Also, the very act of running top may break this weak affinity and cause more processes to change
more often (because of the extra demand for cpu time).
%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
environment, if 'Irix mode' is Off, top will operate in 'Solaris mode' where a task's cpu usage will be divided by the total
CPUs. You toggle 'Irix/Solaris' modes with the 'I' interactive command.
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
its dead children has used. You toggle 'Cumulative mode' with 'S', which is a command-line option and an interactive command.
the 'S' interactive command for additional information regarding this mode.
TIME+ -- CPU Time, hundredths:
The same as 'TIME', but reflecting more granularity through hundredths of a second.
%MEM -- Memory usage (RES): A task's currently used share of available physical memory.
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
VIRT = SWAP + RES
SWAP -- Swapped size (kb):
The swapped out portion of a task's total virtual memory image.
RES -- Resident size (kb):
The non-swapped physical memory a task has used.
RES = CODE + DATA
CODE -- Code size (kb):
The amount of physical memory devoted to executable code, also known as the 'text resident set' size or TRS.
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.
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.
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
nDRT -- 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
responding physical memory location can be used for some other virtual page.
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
run-queue. Even without a true SMP machine, you may see numerous tasks in this state depending on top's delay interval
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
'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
gram 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
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
ing screen width (up to the maximum 512 characters) to provide for the potential growth of program names into command lines.
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
tion 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
be to stop and restart top.
Flags -- Task Flags:
This column represents the task's current scheduling flags which are expressed in hexadecimal notation and with zeros
These flags are officially documented in . Less formal documentation can also be found on the 'Fields select'
'Order fields' screens.