? ? ? ?Listed ?below ?are top's available process fields (columns). ?They
? ? ? ?are shown in strict ascii alphabetical order. ?You ?may ?customize
? ? ? ?their ?position ?and ?whether or not they are displayable with the
? ? ? ?`f' or `F' (Fields Management) interactive commands.

? ? ? ?Any field is selectable as the sort field, and you control whether
? ? ? ?they are sorted high-to-low or low-to-high. ?For additional infor‐
? ? ? ?mation on sort provisions see topic 4c. TASK AREA Commands, ?SORT‐
? ? ? ?ING.

? ? ? ?The ?fields related to physical memory or virtual memory reference
? ? ? ?`(KiB)' which is the unsuffixed display mode. ? Such ?fields ?may,
? ? ? ?however, ?be ?scaled from KiB through PiB. ?That scaling is influ‐
? ? ? ?enced via the `e' interactive command or established ?for ?startup
? ? ? ?through a build option.

? ? ? ?

? ? ? ?1. %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 SMP environment, if a process is multi-threaded ?and
? ? ? ? ? ?top ?is ?not ?operating ?in Threads mode, amounts greater than
? ? ? ? ? ?100% may be reported. ?You toggle Threads mode ?with ?the ?`H'
? ? ? ? ? ?interactive command.

? ? ? ? ? ?Also ?for ?multi-processor ?environments, if Irix mode is Off,
? ? ? ? ? ?top will operate in Solaris mode where a task's cpu usage will
? ? ? ? ? ?be ? divided ? by ?the ?total ?number ?of ?CPUs. ? You ?toggle
? ? ? ? ? ?Irix/Solaris modes with the `I' interactive command.

? ? ? ? 2. %MEM ?-- ?Memory Usage (RES)

? ? ? ? ? A task's currently used share of available physical memory.

? ? ? ? 3. CGROUPS ?-- ?Control Groups

? ? ? ? ? The names of the control group(s) to which a process ?belongs,
? ? ? ? ? ?or `-' if not applicable for that process.

? ? ? ? ? ?Control ?Groups provide for allocating resources (cpu, memory,
? ? ? ? ? ?network bandwidth, etc.) among installation-defined groups ?of
? ? ? ? ? ?processes. ? They enable fine-grained control over allocating,
? ? ? ? ? ?denying, ? prioritizing, ? managing ? and ? monitoring ? those
? ? ? ? ? ?resources.

? ? ? ? ? ?Many different hierarchies of cgroups can exist simultaneously
? ? ? ? ? ?on a system and each hierarchy is attached to one or more sub‐
? ? ? ? ? ?systems. ?A subsystem represents a single resource.

? ? ? ? ? ?Note: ?The ?CGROUPS ?field, unlike most columns, is not fixed-
? ? ? ? ? ?width. ?When displayed, it plus any other variable width ?col‐
? ? ? ? ? ?umns ?will ?be allocated all remaining screen width (up to the
? ? ? ? ? ?maximum 512 characters). ?Even so, such variable width ?fields
? ? ? ? ? ?could still suffer truncation. ?See topic 5c. SCROLLING a Win‐
? ? ? ? ? ?dow for additional ?information ?on ?accessing ?any ?truncated
? ? ? ? ? ?data.

? ? ? ? 4. CODE ?-- ?Code Size (KiB)

? ? ? ? ? The amount of physical memory devoted to executable code, also
? ? ? ? ? ?known as the Text Resident Set size or TRS.

? ? ? ? 5. COMMAND ?-- ?Command Name or Command Line

? ? ? ? ? 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 ?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
? ? ? ? ? ?the program name in brackets, as in this example:
? ? ? ? ? ? ? ?[kthreadd]

? ? ? ? ? ?This ?field ?may ?also ?be impacted by the forest view display
? ? ? ? ? ?mode. ?See the `V' interactive command for additional informa‐
? ? ? ? ? ?tion regarding that mode.

? ? ? ? ? ?Note: ?The ?COMMAND ?field, unlike most columns, is not fixed-
? ? ? ? ? ?width. ?When displayed, it plus any other variable width ?col‐
? ? ? ? ? ?umns ?will ?be allocated all remaining screen width (up to the
? ? ? ? ? ?maximum 512 characters). ?Even so, such variable width ?fields
? ? ? ? ? ?could ?still ?suffer ?truncation. ?This is especially true for
? ? ? ? ? ?this field when command lines are ?being ?displayed ?(the ?`c'
? ? ? ? ? ?interactive ?command.) ? See ?topic 5c. SCROLLING a Window for
? ? ? ? ? ?additional information on accessing any truncated data.

? ? ? ? 6. DATA ?-- ?Data + Stack Size (KiB)

? ? ? ? ? The amount of physical memory devoted to other than executable
? ? ? ? ? ?code, also known as the Data Resident Set size or DRS.

? ? ? ? 7. ENVIRON ?-- ?Environment variables

? ? ? ? ? Display ?all ?of the environment variables, if any, as seen by
? ? ? ? ? ?the respective processes. ?These variables will ?be ?displayed
? ? ? ? ? ?in their raw native order, not the sorted order you are accus‐
? ? ? ? ? ?tomed to seeing with an unqualified `set'.

? ? ? ? ? ?Note: The ENVIRON field, unlike most columns, ?is ?not ?fixed-
? ? ? ? ? ?width. ? When displayed, it plus any other variable width col‐
? ? ? ? ? ?umns will be allocated all remaining screen width (up ?to ?the
? ? ? ? ? ?maximum ?512 characters). ?Even so, such variable width fields
? ? ? ? ? ?could still suffer truncation. ?This is ?especially ?true ?for
? ? ? ? ? ?this ?field. ? See topic 5c. SCROLLING a Window for additional
? ? ? ? ? ?information on accessing any truncated data.

? ? ? ? 8. Flags ?-- ?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>.

? ? ? ? 9. GID ?-- ?Group Id

? ? ? ? ? The effective group ID.

? ? ? ?10. GROUP ?-- ?Group Name

? ? ? ? ? The effective group name.

? ? ? ?11. NI ?-- ?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 dispatch-ability.

? ? ? ?12. P ?-- ?Last used CPU (SMP)

? ? ? ? ? A number representing the last used processor. ?In a true ?SMP
? ? ? ? ? ?environment ?this will likely change frequently since the ker‐
? ? ? ? ? ?nel intentionally uses weak affinity. ?Also, the very ?act ?of
? ? ? ? ? ?running ?top ?may break this weak affinity and cause more pro‐
? ? ? ? ? ?cesses to change CPUs more often (because of the extra ?demand
? ? ? ? ? ?for cpu time).

? ? ? ?13. PGRP ?-- ?Process Group Id

? ? ? ? ? Every ?process ?is ?member ?of a unique process group which is
? ? ? ? ? ?used for distribution of signals and by terminals to arbitrate
? ? ? ? ? ?requests ?for ?their input and output. ?When a process is cre‐
? ? ? ? ? ?ated (forked), it becomes a member of the process group of its
? ? ? ? ? ?parent. ? By convention, this value equals the process ID (see
? ? ? ? ? ?PID) of the first ?member ?of ?a ?process ?group, ?called ?the
? ? ? ? ? ?process group leader.

? ? ? ?14. PID ?-- ?Process Id

? ? ? ? ? The task's unique process ID, which periodically wraps, though
? ? ? ? ? ?never restarting at zero. ?In kernel terms, it is a ?dispatch‐
? ? ? ? ? ?able entity defined by a task_struct.

? ? ? ? ? ?This value may also be used as: a process group ID (see PGRP);
? ? ? ? ? ?a session ID for the session leader (see SID); a thread ?group
? ? ? ? ? ?ID ?for ?the thread group leader (see TGID); and a TTY process
? ? ? ? ? ?group ID for the process group leader (see TPGID).

? ? ? ?15. PPID ?-- ?Parent Process Id

? ? ? ? ? The process ID (pid) of a task's parent.

? ? ? ?16. PR ?-- ?Priority

? ? ? ? ? The scheduling priority of the task. ?If you see `rt' in ?this
? ? ? ? ? ?field, it means the task is running under real time scheduling
? ? ? ? ? ?priority.

? ? ? ? ? ?Under linux, real time priority is somewhat ?misleading ?since
? ? ? ? ? ?traditionally ?the ?operating itself was not preemptible. ?And
? ? ? ? ? ?while the 2.6 kernel can be made mostly preemptible, it is not
? ? ? ? ? ?always so.

? ? ? ?17. RES ?-- ?Resident Memory Size (KiB)

? ? ? ? ? The non-swapped physical memory a task is using.

? ? ? ?18. RUID ?-- ?Real User Id

? ? ? ? ? The real user ID.

? ? ? ?19. RUSER ?-- ?Real User Name

? ? ? ? ? The real user name.

? ? ? ?20. S ?-- ?Process Status

? ? ? ? ? The status of the task which can be one of:
? ? ? ? ? ? ? ?D = uninterruptible sleep
? ? ? ? ? ? ? ?R = running
? ? ? ? ? ? ? ?S = sleeping
? ? ? ? ? ? ? ?T = stopped by job control signal
? ? ? ? ? ? ? ?t = stopped by debugger during trace
? ? ? ? ? ? ? ?Z = zombie

? ? ? ? ? ?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.

? ? ? ?21. SHR ?-- ?Shared Memory Size (KiB)

? ? ? ? ? The ?amount ?of ?shared memory available to a task, not all of
? ? ? ? ? ?which is typically resident. ?It simply reflects ?memory ?that
? ? ? ? ? ?could be potentially shared with other processes.

? ? ? ?22. SID ?-- ?Session Id

? ? ? ? ? A ?session ?is a collection of process groups (see PGRP), usu‐
? ? ? ? ? ?ally established by the login shell. ?A newly ?forked ?process
? ? ? ? ? ?joins ?the ?session of its creator. ?By convention, this value
? ? ? ? ? ?equals the process ID (see PID) of the ?first ?member ?of ?the
? ? ? ? ? ?session, called the session leader, which is usually the login
? ? ? ? ? ?shell.

? ? ? ?23. SUID ?-- ?Saved User Id

? ? ? ? ? The saved user ID.

? ? ? ?24. SUPGIDS ?-- ?Supplementary Group IDs

? ? ? ? ? The IDs of any supplementary group(s) established at login ?or
? ? ? ? ? ?inherited from a task's parent. ?They are displayed in a comma
? ? ? ? ? ?delimited list.

? ? ? ? ? ?Note: The SUPGIDS field, unlike most columns, ?is ?not ?fixed-
? ? ? ? ? ?width. ? When displayed, it plus any other variable width col‐
? ? ? ? ? ?umns will be allocated all remaining screen width (up ?to ?the
? ? ? ? ? ?maximum ?512 characters). ?Even so, such variable width fields
? ? ? ? ? ?could still suffer truncation. ?See topic 5c. SCROLLING a Win‐
? ? ? ? ? ?dow ?for ?additional ?information ?on ?accessing any truncated
? ? ? ? ? ?data.

? ? ? ?25. SUPGRPS ?-- ?Supplementary Group Names

? ? ? ? ? The names of any supplementary group(s) established ?at ?login
? ? ? ? ? ?or ?inherited ?from ?a task's parent. ?They are displayed in a
? ? ? ? ? ?comma delimited list.

? ? ? ? ? ?Note: The SUPGRPS field, unlike most columns, ?is ?not ?fixed-
? ? ? ? ? ?width. ? When displayed, it plus any other variable width col‐
? ? ? ? ? ?umns will be allocated all remaining screen width (up ?to ?the
? ? ? ? ? ?maximum ?512 characters). ?Even so, such variable width fields
? ? ? ? ? ?could still suffer truncation. ?See topic 5c. SCROLLING a Win‐
? ? ? ? ? ?dow ?for ?additional ?information ?on ?accessing any truncated
? ? ? ? ? ?data.

? ? ? 26. SUSER ?-- ?Saved User Name

? ? ? ? ? The saved user name.

? ? ? ?27. SWAP ?-- ?Swapped Size (KiB)

? ? ? ? ? The non-resident portion of a task's address space.

? ? ? ?28. TGID ?-- ?Thread Group Id

? ? ? ? ? The ID of the thread group to which a task belongs. ?It is the
? ? ? ? ? ?PID ?of ?the ?thread group leader. ?In kernel terms, it repre‐
? ? ? ? ? ?sents those tasks that share an mm_struct.

? ? ? ?29. TIME ?-- ?CPU Time

? ? ? ? ? Total CPU time the task has used since it started. ?When Cumu‐
? ? ? ? ? ?lative ?mode ?is ?On, each process is listed with the cpu time
? ? ? ? ? ?that it and its dead children have used. ?You ?toggle ?Cumula‐
? ? ? ? ? ?tive mode with `S', which is both a command-line option and an
? ? ? ? ? ?interactive command. ?See ?the ?`S' ?interactive ?command ?for
? ? ? ? ? ?additional information regarding this mode.

? ? ? ?30. TIME+ ?-- ?CPU Time, hundredths

? ? ? ? ? The same as TIME, but reflecting more granularity through hun‐
? ? ? ? ? ?dredths of a second.

? ? ? ?31. TPGID ?-- ?Tty Process Group Id

? ? ? ? ? The process group ID of the foreground process ?for ?the ?con‐
? ? ? ? ? ?nected tty, or -1 if a process is not connected to a terminal.
? ? ? ? ? ?By convention, this value equals the process ID (see ?PID) ?of
? ? ? ? ? ?the process group leader (see PGRP).

? ? ? ?32. TTY ?-- ?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.

? ? ? ?33. UID ?-- ?User Id

? ? ? ? ? The effective user ID of the task's owner.

? ? ? ?34. USED ?-- ?Memory in Use (KiB)

? ? ? ? ? This ?field ?represents the non-swapped physical memory a task
? ? ? ? ? ?has used (RES) plus the non-resident portion ?of ?its ?address
? ? ? ? ? ?space (SWAP).

? ? ? ?35. USER ?-- ?User Name

? ? ? ? ? The effective user name of the task's owner.

? ? ? ?36. VIRT ?-- ?Virtual Memory Size (KiB)

? ? ? ? ? The ?total ?amount ?of ?virtual ?memory ?used by the task. ?It
? ? ? ? ? ?includes all code, data and shared libraries plus ?pages ?that
? ? ? ? ? ?have ?been swapped out and pages that have been mapped but not
? ? ? ? ? ?used.

? ? ? ?37. WCHAN ?-- ?Sleeping in Function

? ? ? ? ? Depending on the availability of the ?kernel ?link ?map ?(Sys‐
? ? ? ? ? ?tem.map), ?this field will show the name or the address of the
? ? ? ? ? ?kernel function in which the task is currently sleeping. ?Run‐
? ? ? ? ? ?ning tasks will display a dash ('-') in this column.

? ? ? ? ? ?By ?displaying ?this ?field, ?top's ?own ?working set could be
? ? ? ? ? ?increased by over 700Kb, ?depending ?on ?the ?kernel ?version.
? ? ? ? ? ?Should ?that ?occur, your only means of reducing that overhead
? ? ? ? ? ?will be to stop and restart top.

? ? ? ?38. nDRT ?-- ?Dirty Pages Count

? ? ? ? ? The number of pages that have been modified ?since ?they ?were
? ? ? ? ? ?last ?written to auxiliary storage. ?Dirty pages must be writ‐
? ? ? ? ? ?ten to auxiliary storage ?before ?the ?corresponding ?physical
? ? ? ? ? ?memory location can be used for some other virtual page.

? ? ? ?39. nMaj ?-- ?Major 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 ?auxiliary ?storage
? ? ? ? ? ?access is involved in making that page available.

? ? ? ?40. nMin ?-- ?Minor Page Fault count

? ? ? ? ? The number of minor 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 minor page fault does not involve ?auxiliary
? ? ? ? ? ?storage access in making that page available.

? ? ? ?41. nTH ?-- ?Number of Threads

? ? ? ? ? The number of threads associated with a process.

? ? ? ?42. nsIPC ?-- ?IPC namespace

? ? ? ? ? The Inode of the namespace used to isolate interprocess commu‐
? ? ? ? ? ?nication (IPC) resources such as ?System ?V ?IPC ?objects ?and
? ? ? ? ? ?POSIX message queues.

? ? ? ?43. nsMNT ?-- ?MNT namespace

? ? ? ? ? The ?Inode ?of ?the namespace used to isolate filesystem mount
? ? ? ? ? ?points thus offering different views of the filesystem hierar‐
? ? ? ? ? ?chy.

? ? ? ?44. nsNET ?-- ?NET namespace

? ? ? ? ? The ?Inode ?of the namespace used to isolate resources such as
? ? ? ? ? ?network devices, IP addresses, IP routing, port numbers, etc.

? ? ? ?45. nsPID ?-- ?PID namespace

? ? ? ? ? The Inode of the namespace used to isolate process ID ?numbers
? ? ? ? ? ?meaning ?they ?need not remain unique. ?Thus, each such names‐
? ? ? ? ? ?pace could have its own `init' (PID #1) to manage various ini‐
? ? ? ? ? ?tialization tasks and reap orphaned child processes.

? ? ? ?46. nsUSER ?-- ?USER namespace

? ? ? ? ? The ?Inode of the namespace used to isolate the user and group
? ? ? ? ? ?ID numbers. ?Thus, a process could have a normal ?unprivileged
? ? ? ? ? ?user ?ID outside a user namespace while having a user ID of 0,
? ? ? ? ? ?with full root privileges, inside that namespace.