pstree ( process tree)
- ps 에 의해 출력되는 프로세스 정보를 트리 형태로 나타냅니다.

매뉴얼

NAME

       pstree - display a tree of processes

SYNOPSIS

       pstree [-a] [-c] [-h|-Hpid] [-l] [-n] [-p] [-u] [-Z] [-A|-G|-U]

       [pid|user]

       pstree -V

DESCRIPTION

       pstree shows running processes as a tree. The tree is rooted at  either

       pid or init if pid is omitted. If a user name is specified, all process

       trees rooted at processes owned by that user are shown.

       pstree visually merges identical branches by  putting  them  in  square

       brackets and prefixing them with the repetition count, e.g.

           init-+-getty

                |-getty

                |-getty

                '-getty

       becomes

           init---4*[getty]

       Child  threads  of a process are found under the parent process and are

       shown with the process name in curly braces, e.g.

           icecast2---13*[{icecast2}]

       If pstree is called as pstree.x11 then it will prompt the user  at  the

       end of the line to press return and will not return until that has hap-

       pened. This is useful for when pstree is run in a xterminal.

OPTIONS

       -a     Show command line arguments. If the command line of a process is

              swapped out, that process is shown in parentheses. -a implicitly

              disables compaction.

       -A     Use ASCII characters to draw the tree.

       -c     Disable compaction of identical subtrees. By  default,  subtrees

              are compacted whenever possible.

       -G     Use VT100 line drawing characters.

       -h     Highlight the current process and its ancestors. This is a no-op

              if the terminal doesn't support highlighting or if  neither  the

              current  process  nor  any  of  its ancestors are in the subtree

              being shown.

       -H     Like -h, but highlight the  specified  process  instead.  Unlike

              with  -h,  pstree  fails  when  using  -H if highlighting is not

              available.

-l     Display long lines. By default, lines are truncated to the  dis-

              play  width or 132 if output is sent to a non-tty or if the dis-

              play width is unknown.

       -n     Sort processes with the same ancestor by PID instead of by name.

              (Numeric sort.)

       -p     Show  PIDs.  PIDs  are  shown  as decimal numbers in parentheses

              after each process name. -p implicitly disables compaction.

       -u     Show uid transitions. Whenever the uid of a process differs from

              the uid of its parent, the new uid is shown in parentheses after

              the process name.

       -U     Use UTF-8 (Unicode) line drawing characters. Under Linux  1.1-54

              and  above,  UTF-8  mode  is entered on the console with echo -e

              '\033%8' and left with echo -e '\033%@'

       -V     Display version information.

       -Z     (SELinux) Show security context for each process.

FILES

       /proc     location of the proc file system

AUTHORS

       Werner     Almesberger     <werner@almesberger.net>     Craig     Small

       <csmall@small.dropbear.id.au>

BUGS

       Some character sets may be incompatible with the VT100 characters.

SEE ALSO

       ps(1), top(1).

top
- cpu와 메모리를 사용하는 작업들에 대한 시스템 정보를 출력합니다.

[TOP 실행중 정렬하기]

SHIFT+P : CPU 사용률이 많은 프로세스 순서대로 정렬

SHIFT+M : MEMORY 사용률이 많은 프로세스 순서대로 정렬

SHIFT+T : 실행시간이 오래된 프로세스 순서대로 정렬

SHIFT + b : 주요값을 밝게표시

[TOP 실행중 사용가능 명령어]

i : idle 프로세스를 보이지않는다. (Running 상태의 프로세스들만 확인)
k : 프로세스를 죽일때 사용. PID를 입력하여 프로세스를 종료시킨다.
r : 프로세스 우선순위 변경. PID를 입력하여 프로세스 우선순위를 변경한다. 우선순의 값은 (+20 ~ -20까지), renice 명령어와 같은역할.
u : 특정사용자가 실행한 프로세스 확인. UID를 입력하여 프로세스를 확인한다.

[필드]

필드편집 : 실행중 'o' 입력

PRI : 프로세스의 우선순위

NI : 프로세스의 NICE 값

RES : Resident Size (상주메모리)

MAN 페이지참고

2a. DESCRIPTIONS of Fields

       Listed below are top’s available fields.  They are always associated with the letter shown, regardless of the position you may  have  established  for them with the ’o’ (Order fields) interactive command.

       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.

       a: PID  --  Process Id
          The task’s unique process ID, which periodically wraps, though never restarting at zero.

       b: PPID  --  Parent Process Pid
          The process ID of a task’s parent.

       c: RUSER  --  Real User Name
          The real user name of the task’s owner.

       d: UID  --  User Id
          The effective user ID of the task’s owner.

       e: USER  --  User Name
          The effective user name of the task’s owner.

       f: GROUP  --  Group Name
          The effective group name of the task’s owner.

       g: 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.

       h: PR  --  Priority
          The priority of the task.

       i: 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 dispatchability.

       j: #C  --  Last used CPU (SMP)
          A number representing the last used processor.  In a true SMP environment this will likely change frequently since  the  kernel  intentionally  uses  weak  affinity.   Also,  the  very  act  of  running top may break this weak affinity and cause more processes to change CPUs more often (because of the extra demand for cpu time).

       k: %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  environ-ment,  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.

       l: 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  it  and  its dead children has used.  You toggle ’Cumulative mode’ with ’S’, which is a command-line option and an interactive command.  See the ’S’ inter-active command for additional information regarding this mode.

       m: TIME+  --  CPU Time, hundredths
          The same as ’TIME’, but reflecting more granularity through hundredths of a second.

       n: %MEM  --  Memory usage (RES)
          A task’s currently used share of available physical memory.

       o: 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 been swapped out.

          VIRT = SWAP + RES.

       p: SWAP  --  Swapped size (kb)
          The swapped out portion of a task’s total virtual memory image.

       q: RES  --  Resident size (kb)
          The non-swapped physical memory a task has used.

          RES = CODE + DATA.

       r: CODE  --  Code size (kb)
          The amount of physical memory devoted to executable code, also known as the ’text resident set’ size or TRS.

       s: 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.

       t: 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.

       u: 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 that page available.

       v: 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 corresponding physical memory location can be used for some other virtual page.

       w: 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  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.

       x: 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 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 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.

       y: 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 kernel function 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 will  be  to
          stop and restart top.

       z: 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>.  Less formal documentation can also be found on the ’Fields select’ and ’Order fields’  screens.

2b. SELECTING and ORDERING Columns
      

       After pressing the interactive commands ’f’ (Fields select) or ´o’ (Order fields) you will be shown a screen containing the current fields string followed by names and descriptions for all fields.

       Here is a sample fields string from one of top’s four windows/field groups and an explanation of the conventions used:

       -  Sample fields string:
             ANOPQRSTUVXbcdefgjlmyzWHIK

       -  The order of displayed fields corresponds to the order of the letters in that string.

       -  If the letter is upper case the corresponding field itself will then be shown as part of the task display  (screen  width  permitting).   This  will also be indicated by a leading asterisk (’*’), as in this excerpt:
              ...
              * K: %CPU       = CPU usage
                l: TIME       = CPU Time
                m: TIME+      = CPU Time, hundredths
              * N: %MEM       = Memory usage (RES)
              * O: VIRT       = Virtual Image (kb)
              ...

       Fields select screen  --  the ’f’ interactive command
          You toggle the display of a field by simply pressing the corresponding letter.

       Order fields screen  --  the ’o’ interactive command
          You move a field to the left by pressing the corresponding upper case letter and to the right with the lower case letter.

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