Provided by: atop_2.3.0-1build1_amd64 bug

NAME

       atop - Advanced System & Process Monitor

SYNOPSIS

       Interactive Usage:

       atop   [-g|-m|-d|-n|-u|-p|-s|-c|-v|-o|-y]   [-C|-M|-D|-N|-A]   [-afFG1xR]   [-L   linelen]
       [-Plabel[,label]...]  [ interval [ samples ]]

       Writing and reading raw logfiles:

       atop -w rawfile [-a] [-S] [ interval [ samples ]]
       atop  -r  [  rawfile  ]  [-b  hh:mm  ]  [-e  hh:mm  ]   [-g|-m|-d|-n|-u|-p|-s|-c|-v|-o|-y]
       [-C|-M|-D|-N|-A] [-fFG1xR] [-L linelen] [-Plabel[,label]...]

DESCRIPTION

       The  program  atop is an interactive monitor to view the load on a Linux system.  It shows
       the occupation of the most critical hardware resources (from a performance point of  view)
       on system level, i.e. cpu, memory, disk and network.
       It  also  shows which processes are responsible for the indicated load with respect to cpu
       and memory load on process level.  Disk load is shown per process if "storage  accounting"
       is active in the kernel.  Network load is shown per process if the kernel module `netatop'
       has been installed.

       Every interval (default: 10 seconds) information is shown about the resource occupation on
       system  level  (cpu,  memory,  disks  and network layers), followed by a list of processes
       which have been active during the  last  interval  (note  that  all  processes  that  were
       unchanged  during  the last interval are not shown, unless the key 'a' has been pressed or
       unless sorting on memory occupation is done).  If the list of active  processes  does  not
       entirely  fit  on  the  screen,  only  the  top  of  the list is shown (sorted in order of
       activity).
       The intervals are repeated till the number of samples (specified as command  argument)  is
       reached, or till the key 'q' is pressed in interactive mode.

       When  atop  is  started,  it  checks whether the standard output channel is connected to a
       screen, or to a file/pipe. In the first case it produces screen  control  codes  (via  the
       ncurses  library)  and  behaves  interactively; in the second case it produces flat ASCII-
       output.

       In interactive mode, the output of atop scales dynamically to the  current  dimensions  of
       the screen/window.
       If the window is resized horizontally, columns will be added or removed automatically. For
       this purpose, every column has a particular weight. The columns with the  highest  weights
       that fit within the current width will be shown.
       If  the  window  is  resized vertically, lines of the process/thread list will be added or
       removed automatically.

       Furthermore in interactive  mode  the  output  of  atop  can  be  controlled  by  pressing
       particular  keys.   However it is also possible to specify such key as flag on the command
       line. In that case atop switches to the indicated mode on beforehand;  this  mode  can  be
       modified  again  interactively.  Specifying  such  key  as  flag is especially useful when
       running atop with output to a pipe or file (non-interactively).  These flags are the  same
       as the keys that can be pressed in interactive mode (see section INTERACTIVE COMMANDS).
       Additional  flags are available to support storage of atop-data in raw format (see section
       RAW DATA STORAGE).

PROCESS ACCOUNTING

       With every interval, atop reads the kernel administration to obtain information about  all
       running  processes.   However,  it  is likely that during the interval also processes have
       terminated.  These processes might have consumed system resources during this interval  as
       well  before they terminated.  Therefor, atop tries to read the process accounting records
       that contain the accounting information of terminated processes and report these processes
       too.   Only  when  the process accounting mechanism in the kernel is activated, the kernel
       writes such process accounting record to a file for every process that terminates.

       There are various ways for atop to get access to the process accounting records (tried  in
       this order):

       1.  When  the  environment  variable ATOPACCT is set, it specifies the name of the process
           accounting file.  In that case, process accounting for  this  file  should  have  been
           activated  on  beforehand.   Before opening this file for reading, atop drops its root
           privileges (if any).
           When this  environment  variable  is  present  but  its  contents  is  empty,  process
           accounting will not be used at all.

       2.  This is the preferred way of handling process accounting records!
           When the atopacctd daemon is active, it has activated the process accounting mechanism
           in the kernel and transfers to original accounting records to shadow files.   In  that
           case, atop drops its root privileges and opens the current shadow file for reading.
           This  way  is  preferred,  because  the atopacctd daemon maintains full control of the
           sizes of the original process accounting file (written by the kernel) and  the  shadow
           files  (read  by  the atop processes). For further information, refer to the atopacctd
           man page.

       3.  When the atopacctd daemon is not active,  atop  verifies  if  the  process  accounting
           mechanism has been switched on via the separate psacct package. In that case, the file
           /var/account/pacct is in use as process accounting file and atop opens this  file  for
           reading.

       4.  As  a last possibility, atop itself tries to activate the process accounting mechanism
           (requires root privileges) using the file /var/cache/atop.d/atop.acct (to  be  written
           by  the  kernel, to be read by atop itself). Process accounting remains active as long
           as at least one atop process is alive.  Whenever the last atop process  stops  (either
           by  pressing  `q'  or  by `kill -15'), it deactivates the process accounting mechanism
           again. Therefor you should never terminate atop by `kill -9', because then it  has  no
           chance to stop process accounting.  As a result, the accounting file may consume a lot
           of disk space after a while.
           To avoid that the process accounting file consumes too much disk space, atop  verifies
           at  the end of every sample if the size of the process accounting file exceeds 200 MiB
           and if this atop process is the only one that is currently using the  file.   In  that
           case the file is truncated to a size of zero.

           Notice  that  root-privileges  are required to switch on/off process accounting in the
           kernel. You can start atop as a root user or specify  setuid-root  privileges  to  the
           executable  file.   In  the latter case, atop switches on process accounting and drops
           the root-privileges again.
           If atop does not run with root-privileges, it does not show information about finished
           processes.   It indicates this situation with the message message `no procacct` in the
           top-right corner (instead of the counter that shows the number of exited processes).

       When during one interval a lot of processes have finished, atop might grow tremendously in
       memory  when  reading  all process accounting records at the end of the interval. To avoid
       such excessive growth, atop will never read more than 50 MiB with process information from
       the  process  accounting  file  per  interval  (approx.  70000  finished  processes).   In
       interactive mode a warning is given whenever processes have been skipped for this reason.

COLORS

       For the resource consumption on system level, atop uses colors to indicate that a critical
       occupation  percentage  has been (almost) reached.  A critical occupation percentage means
       that is likely that this load causes  a  noticeable  negative  performance  influence  for
       applications using this resource. The critical percentage depends on the type of resource:
       e.g. the performance influence of a disk with a busy  percentage  of  80%  might  be  more
       noticeable for applications/user than a CPU with a busy percentage of 90%.
       Currently  atop  uses  the following default values to calculate a weighted percentage per
       resource:

        Processor
            A busy percentage of 90% or higher is considered `critical'.

        Disk
            A busy percentage of 70% or higher is considered `critical'.

        Network
            A busy percentage of 90% or higher  for  the  load  of  an  interface  is  considered
            `critical'.

        Memory
            An  occupation  percentage  of  90%  is  considered  `critical'.   Notice  that  this
            occupation percentage is the accumulated memory consumption of the kernel  (including
            slab)  and  all  processes;  the memory for the page cache (`cache' and `buff' in the
            MEM-line) and the reclaimable part of the slab (`slrec`) is not implied!
            If the number of pages swapped out (`swout' in the PAG-line) is larger  than  10  per
            second,  the  memory  resource  is  considered `critical'.  A value of at least 1 per
            second is considered `almost critical'.
            If the committed virtual memory exceeds the limit (`vmcom' and `vmlim'  in  the  SWP-
            line), the SWP-line is colored due to overcommitting the system.

        Swap
            An  occupation percentage of 80% is considered `critical' because swap space might be
            completely exhausted in the near future; it is not critical from a performance point-
            of-view.

       These  default  values can be modified in the configuration file (see separate man-page of
       atoprc).

       When a resource exceeds its critical occupation percentage, the concerning values  in  the
       screen line are colored red by default.
       When  a  resource  exceeded  (default)  80%  of  its  critical percentage (so it is almost
       critical), the concerning values in the screen line are  colored  cyan  by  default.  This
       `almost  critical  percentage'  (one  value  for  all  resources)  can  be modified in the
       configuration file (see separate man-page of atoprc).
       The default colors red and cyan can be modified in the configuration  file  as  well  (see
       separate man-page of atoprc).

       With the key 'x' (or flag -x), the use of colors can be suppressed.

NETATOP MODULE

       Per-process  and per-thread network activity can be measured by the netatop kernel module.
       You can download this kernel module from the website (mentioned at the end of this  manual
       page) and install it on your system if the kernel version is 2.6.24 or newer.
       When  atop  gathers  counters  for  a  new  interval, it verifies if the netatop module is
       currently active. If so, atop obtains the relevant network counters from this  module  and
       shows  the  number  of sent and received packets per process/thread in the generic screen.
       Besides, detailed counters can be requested by pressing the `n' key.
       When the netatopd daemon is running as well, atop  also  reads  the  network  counters  of
       exited processes that are logged by this daemon (comparable with process accounting).

       More  information  about the optional netatop kernel module and the netatopd daemon can be
       found in the concerning man-pages and on the website mentioned at the end of  this  manual
       page.

INTERACTIVE COMMANDS

       When  running  atop  interactively (no output redirection), keys can be pressed to control
       the output. In general, lower case keys can be used to  show  other  information  for  the
       active processes and upper case keys can be used to influence the sort order of the active
       process/thread list.

       g    Show generic output (default).

            Per process the following fields are shown in case of a window-width of 80 positions:
            process-id,  cpu  consumption  during  the last interval in system and user mode, the
            virtual and resident memory growth of the process.

            The subsequent columns depend on the used kernel:
            When the kernel supports "storage accounting" (>=  2.6.20),  the  data  transfer  for
            read/write  on  disk,  the status and exit code are shown for each process.  When the
            kernel does not support "storage accounting", the username, number of threads in  the
            thread group, the status and exit code are shown.
            When  the  kernel  module  'netatop' is loaded, the data transfer for send/receive of
            network packets is shown for each process.
            The last columns contain the state, the occupation percentage for the chosen resource
            (default: cpu) and the process name.

            When more than 80 positions are available, other information is added.

       m    Show memory related output.

            Per process the following fields are shown in case of a window-width of 80 positions:
            process-id, minor and major memory faults, size of virtual shared text, total virtual
            process  size,  total  resident process size, virtual and resident growth during last
            interval, memory occupation percentage and process name.

            When more than 80 positions are available, other information is added.

            For memory consumption, always all processes are shown (also the processes that  were
            not active during the interval).

       d    Show disk-related output.

            When  "storage  accounting"  is active in the kernel, the following fields are shown:
            process-id, amount of data read from disk, amount of data written to disk, amount  of
            data  that  was  written  but  has  been  withdrawn  again  (WCANCL), disk occupation
            percentage and process name.

       n    Show network related output.

            Per process the following fields are shown in case of a window-width of 80 positions:
            process-id, thread-id, total bandwidth for received packets, total bandwidth for sent
            packets, number of received TCP packets with the average size per packet (in  bytes),
            number  of  sent  TCP  packets with the average size per packet (in bytes), number of
            received UDP packets with the average size per packet (in bytes), number of sent  UDP
            packets  with  the  average  size  per  packet  (in  bytes),  the  network occupation
            percentage and process name.
            This information can only be shown when kernel module `netatop' is installed.

            When more than 80 positions are available, other information is added.

       s    Show scheduling characteristics.

            Per process the following fields are shown in case of a window-width of 80 positions:
            process-id,  number  of  threads  in  state 'running' (R), number of threads in state
            'interruptible sleeping' (S), number of threads in state  'uninterruptible  sleeping'
            (D),  scheduling  policy  (normal  timesharing, realtime round-robin, realtime fifo),
            nice value, priority, realtime priority, current processor, status, exit code, state,
            the occupation percentage for the chosen resource and the process name.

            When more than 80 positions are available, other information is added.

       v    Show various process characteristics.

            Per process the following fields are shown in case of a window-width of 80 positions:
            process-id, user name and group, start date and time, status (e.g. exit code  if  the
            process  has  finished), state, the occupation percentage for the chosen resource and
            the process name.

            When more than 80 positions are available, other information is added.

       c    Show the command line of the process.

            Per process the following fields are shown: process-id, the occupation percentage for
            the chosen resource and the command line including arguments.

       o    Show the user-defined line of the process.

            In  the  configuration  file  the  keyword  ownprocline  can  be  specified  with the
            description of a user-defined output-line.
            Refer to the man-page of atoprc for a detailed description.

       y    Show the individual threads within a process (toggle).

            Single-threaded processes are still shown as one line.
            For multi-threaded processes, one line represents the process while additional  lines
            show  the  activity  per  individual  thread (in a different color). Depending on the
            option 'a' (all or active toggle), all threads are shown or  only  the  threads  that
            were active during the last interval.
            Whether this key is active or not can be seen in the header line.

       u    Show the process activity accumulated per user.

            Per  user  the  following  fields are shown: number of processes active or terminated
            during last interval (or in total if combined  with  command  `a'),  accumulated  cpu
            consumption  during  last  interval  in system and user mode, the current virtual and
            resident memory space consumed by active processes (or all processes of the  user  if
            combined with command `a').
            When  "storage  accounting"  is  active in the kernel, the accumulated read and write
            throughput on disk is shown.  When the kernel module `netatop'  has  been  installed,
            the number of received and sent network packets are shown.
            The  last  columns  contain  the  accumulated  occupation  percentage  for the chosen
            resource (default: cpu) and the user name.

       p    Show the process activity accumulated per program (i.e. process name).

            Per program the following fields are shown: number of processes active or  terminated
            during  last  interval  (or  in  total if combined with command `a'), accumulated cpu
            consumption during last interval in system and user mode,  the  current  virtual  and
            resident  memory  space consumed by active processes (or all processes of the user if
            combined with command `a').
            When "storage accounting" is active in the kernel, the  accumulated  read  and  write
            throughput  on  disk  is shown.  When the kernel module `netatop' has been installed,
            the number of received and sent network packets are shown.
            The last columns  contain  the  accumulated  occupation  percentage  for  the  chosen
            resource (default: cpu) and the program name.

       j    Show the process activity accumulated per Docker container.

            Per  container  the  following  fields  are  shown:  number  of  processes  active or
            terminated during  last  interval  (or  in  total  if  combined  with  command  `a'),
            accumulated cpu consumption during last interval in system and user mode, the current
            virtual and resident memory space consumed by active processes (or all  processes  of
            the user if combined with command `a').
            When  "storage  accounting"  is  active in the kernel, the accumulated read and write
            throughput on disk is shown.  When the kernel module `netatop'  has  been  installed,
            the number of received and sent network packets are shown.
            The  last  columns  contain  the  accumulated  occupation  percentage  for the chosen
            resource (default: cpu) and the Docker container id (CID).

       C    Sort the current list in the order of cpu consumption  (default).   The  one-but-last
            column changes to ``CPU''.

       M    Sort  the current list in the order of resident memory consumption.  The one-but-last
            column changes to ``MEM''. In case of sorting on memory, the full process  list  will
            be shown (not only the active processes).

       D    Sort  the current list in the order of disk accesses issued.  The one-but-last column
            changes to ``DSK''.

       N    Sort the current list in the order of network bandwidth (received  and  transmitted).
            The one-but-last column changes to ``NET''.

       A    Sort  the  current  list  automatically in the order of the most busy system resource
            during this interval.  The  one-but-last  column  shows  either  ``ACPU'',  ``AMEM'',
            ``ADSK'' or ``ANET'' (the preceding 'A' indicates automatic sorting-order).  The most
            busy resource is determined by comparing the weighted busy-percentages of the  system
            resources, as described earlier in the section COLORS.
            This option remains valid until another sorting-order is explicitly selected again.
            A  sorting-order  for  disk  is only possible when "storage accounting" is active.  A
            sorting-order for network is only  possible  when  the  kernel  module  `netatop'  is
            loaded.

       Miscellaneous interactive commands:

       ?    Request for help information (also the key 'h' can be pressed).

       V    Request for version information (version number and date).

       R    Gather  and  calculate the proportional set size of processes (toggle).  Gathering of
            all values that are needed to calculate the PSIZE of a process is a relatively  time-
            consuming  task, so this key should only be active when analyzing the resident memory
            consumption of processes.

       x    Suppress colors to highlight critical resources (toggle).
            Whether this key is active or not can be seen in the header line.

       z    The pause key can be used to freeze the current situation in order to investigate the
            output  on  the screen. While atop is paused, the keys described above can be pressed
            to show other information about the current list of processes.   Whenever  the  pause
            key is pressed again, atop will continue with a next sample.

       i    Modify  the  interval  timer  (default:  10  seconds).  If  an interval timer of 0 is
            entered, the interval timer is switched off. In that case a new sample  can  only  be
            triggered manually by pressing the key 't'.

       t    Trigger  a  new sample manually. This key can be pressed if the current sample should
            be finished before the timer has exceeded, or if no timer is  set  at  all  (interval
            timer  defined  as  0). In the latter case atop can be used as a stopwatch to measure
            the load being caused by a particular application  transaction,  without  knowing  on
            beforehand how many seconds this transaction will last.

            When viewing the contents of a raw file, this key can be used to show the next sample
            from the file.

       T    When viewing the contents of a raw file, this key can be used to  show  the  previous
            sample from the file.

       b    When  viewing the contents of a raw file, this key can be used to branch to a certain
            timestamp within the file (either forward or backward).

       r    Reset all counters to zero to see the system and process activity since boot again.

            When viewing the contents of a raw file, this key  can  be  used  to  rewind  to  the
            beginning of the file again.

       U    Specify  a  search  string for specific user names as a regular expression.  From now
            on, only (active) processes will be shown from  a  user  which  matches  the  regular
            expression.   The  system  statistics  are  still  system  wide.  If the Enter-key is
            pressed without specifying a name, (active) processes of  all  users  will  be  shown
            again.
            Whether this key is active or not can be seen in the header line.

       I    Specify  a  list  with  one or more PIDs to be selected.  From now on, only processes
            will be shown with a PID which matches one of the given list.  The system  statistics
            are  still  system  wide.   If the Enter-key is pressed without specifying a PID, all
            (active) processes will be shown again.
            Whether this key is active or not can be seen in the header line.

       P    Specify a search string for specific process names as a regular expression.  From now
            on,  only  processes  will be shown with a name which matches the regular expression.
            The system statistics are still system wide.  If the  Enter-key  is  pressed  without
            specifying a name, all (active) processes will be shown again.
            Whether this key is active or not can be seen in the header line.

       /    Specify  a specific command line search string as a regular expression.  From now on,
            only processes  will  be  shown  with  a  command  line  which  matches  the  regular
            expression.   The  system  statistics  are  still  system  wide.  If the Enter-key is
            pressed without specifying a string, all (active) processes will be shown again.
            Whether this key is active or not can be seen in the header line.

       J    Specify a Docker container id of 12 (hexadecimal)  characters.   From  now  on,  only
            processes will be shown that run in that specific Docker container (CID).  The system
            statistics are still system wide.  If the Enter-key is pressed without  specifying  a
            container id, all (active) processes will be shown again.
            Whether this key is active or not can be seen in the header line.

       S    Specify  search  strings  for  specific logical volume names, specific disk names and
            specific network interface names. All search strings are  interpreted  as  a  regular
            expressions.   From  now  on,  only  those  system resources are shown that match the
            concerning regular expression.  If the Enter-key  is  pressed  without  specifying  a
            search string, all (active) system resources of that type will be shown again.
            Whether this key is active or not can be seen in the header line.

       a    The  `all/active'  key  can  be  used to toggle between only showing/accumulating the
            processes that were active during the last interval (default) or showing/accumulating
            all processes.
            Whether this key is active or not can be seen in the header line.

       G    By  default,  atop  shows/accumulates  the processes that are alive and the processes
            that   are   exited   during   the   last   interval.   With   this   key   (toggle),
            showing/accumulating the processes that are exited can be suppressed.
            Whether this key is active or not can be seen in the header line.

       f    Show  a  fixed  (maximum)  number  of header lines for system resources (toggle).  By
            default only the lines are  shown  about  system  resources  (CPUs,  paging,  logical
            volumes,  disks,  network  interfaces)  that  really have been active during the last
            interval.  With this key you can force atop to show lines of  inactive  resources  as
            well.
            Whether this key is active or not can be seen in the header line.

       F    Suppress  sorting  of  system resources (toggle).  By default system resources (CPUs,
            logical volumes, disks, network interfaces) are sorted on utilization.
            Whether this key is active or not can be seen in the header line.

       1    Show relevant counters as an average per second (in the format `..../s')  instead  of
            as a total during the interval (toggle).
            Whether this key is active or not can be seen in the header line.

       l    Limit the number of system level lines for the counters per-cpu, the active disks and
            the network interfaces.  By default lines are shown of all CPUs,  disks  and  network
            interfaces which have been active during the last interval.  Limiting these lines can
            be useful on systems with huge number CPUs, disks or interfaces in order to  be  able
            to run atop on a screen/window with e.g. only 24 lines.
            For   all   mentioned  resources  the  maximum  number  of  lines  can  be  specified
            interactively. When using the flag -l the maximum number of per-cpu lines is  set  to
            0, the maximum number of disk lines to 5 and the maximum number of interface lines to
            3.  These values can be modified again in interactive mode.

       k    Send a signal to an active process (a.k.a. kill a process).

       q    Quit the program.

       PgDn Show the next page of the process/thread list.
            With the arrow-down key the list can be scrolled downwards with single lines.

       ^F   Show the next page of the process/thread list (forward).
            With the arrow-down key the list can be scrolled downwards with single lines.

       PgUp Show the previous page of the process/thread list.
            With the arrow-up key the list can be scrolled upwards with single lines.

       ^B   Show the previous page of the process/thread list (backward).
            With the arrow-up key the list can be scrolled upwards with single lines.

       ^L   Redraw the screen.

RAW DATA STORAGE

       In order to store system and process level statistics  for  long-term  analysis  (e.g.  to
       check  the  system  load  and the active processes running yesterday between 3:00 and 4:00
       PM), atop can store the system and process level statistics in compressed binary format in
       a  raw file with the flag -w followed by the filename.  If this file already exists and is
       recognized as a raw data file, atop will append new samples to the file (starting  with  a
       sample  which  reflects  the  activity since boot); if the file does not exist, it will be
       created.
       All processes/threads are stored in the raw file.
       The interval (default: 10 seconds) and number of samples (default: infinite) can be passed
       as  last  arguments. Instead of the number of samples, the flag -S can be used to indicate
       that atop should finish anyhow before midnight.

       A raw file can be read and visualized again with the flag -r followed by the filename.  If
       no  filename is specified, the file /var/log/atop/atop_YYYYMMDD is opened for input (where
       YYYYMMDD are digits representing the current date).  If a filename  is  specified  in  the
       format  YYYYMMDD  (representing  any  valid date), the file /var/log/atop/atop_YYYYMMDD is
       opened.  If a filename with the symbolic name y is specified, yesterday's daily logfile is
       opened (this can be repeated so 'yyyy' indicates the logfile of four days ago).
       The  samples  from  the  file can be viewed interactively by using the key 't' to show the
       next sample, the key 'T' to show  the  previous  sample,  the  key  'b'  to  branch  to  a
       particular time or the key 'r' to rewind to the begin of the file.
       When  output  is redirected to a file or pipe, atop prints all samples in plain ASCII. The
       default line length is 80 characters in that  case;  with  the  flag  -L  followed  by  an
       alternate line length, more (or less) columns will be shown.
       With the flag -b (begin time) and/or -e (end time) followed by a time argument of the form
       HH:MM, a certain time period within the raw file can be selected.

       When atop is installed, the script atop.daily is stored in the /usr/share/atop  directory.
       This  scripts  takes care that atop is activated every day at midnight to write compressed
       binary data to the file /var/log/atop/atop_YYYYMMDD with an interval of 10 minutes.
       Furthermore the script removes all raw files which are older than four weeks.
       The script is activated via the cron daemon  using  the  file  /etc/cron.d/atop  with  the
       contents
               0 0 * * * root /usr/share/atop/atop.daily

       When  the  package  psacct is installed, the process accounting is automatically restarted
       via the logrotate mechanism. The file /etc/logrotate.d/psaccs_atop takes care that atop is
       finished   just  before  the  rotation  of  the  process  accounting  file  and  the  file
       /etc/logrotate.d/psaccu_atop takes care that atop is restarted again after  the  rotation.
       When the package psacct is not installed, these logrotate-files have no effect.

OUTPUT DESCRIPTION

       The  first  sample  shows  the  system  level activity since boot (the elapsed time in the
       header shows the time since boot).  Note that particular counters could have reached their
       maximum value (several times) and started by zero again, so do not rely on these figures.

       For  every  sample  atop  first  shows  the  lines  related to system level activity. If a
       particular system resource has not been used during the interval, the entire line  related
       to  this  resource  is  suppressed.  So the number of system level lines may vary for each
       sample.
       After that a list is shown of processes which have been active during the  last  interval.
       This  list  is  by default sorted on cpu consumption, but this order can be changed by the
       keys which are previously described.

       If values have to be shown by atop which do not fit in the column width, another format is
       used.  If  e.g. a cpu-consumption of 233216 milliseconds should be shown in a column width
       of 4 positions, it is shown as `233s' (in seconds).  For  large  memory  figures,  another
       unit  is  chosen if the value does not fit (Mb instead of Kb, Gb instead of Mb, Tb instead
       of Gb, ...).  For other values, a kind of exponent notation is used (value 123456789 shown
       in a column of 5 positions gives 123e6).

OUTPUT DESCRIPTION - SYSTEM LEVEL

       The system level information consists of the following output lines:

       PRC  Process and thread level totals.
            This  line  contains  the  total cpu time consumed in system mode (`sys') and in user
            mode (`user'), the total number of processes present at this  moment  (`#proc'),  the
            total  number  of  threads  present  at  this  moment  in  state `running' (`#trun'),
            `sleeping interruptible' (`#tslpi') and `sleeping  uninterruptible'  (`#tslpu'),  the
            number  of zombie processes (`#zombie'), the number of clone system calls (`clones'),
            and the number of processes that ended during the  interval  (`#exit')  when  process
            accounting  is  used.  Instead  of  `#exit` the last column may indicate that process
            accounting could not be activated (`no procacct`).
            If the screen-width does not allow all of these counters, only a relevant  subset  is
            shown.

       CPU  CPU utilization.
            At least one line is shown for the total occupation of all CPUs together.
            In case of a multi-processor system, an additional line is shown for every individual
            processor (with `cpu' in lower case), sorted on activity. Inactive CPUs will  not  be
            shown by default.  The lines showing the per-cpu occupation contain the cpu number in
            the last field.

            Every line contains the percentage of cpu time spent in kernel  mode  by  all  active
            processes  (`sys'), the percentage of cpu time consumed in user mode (`user') for all
            active processes (including processes running with a nice value  larger  than  zero),
            the  percentage  of  cpu time spent for interrupt handling (`irq') including softirq,
            the percentage of unused cpu time  while  no  processes  were  waiting  for  disk-I/O
            (`idle'),  and  the  percentage  of  unused  cpu  time while at least one process was
            waiting for disk-I/O (`wait').
            In case of per-cpu occupation, the last column shows the  cpu  number  and  the  wait
            percentage  (`w')  for  that cpu.  The number of lines showing the per-cpu occupation
            can be limited.

            For  virtual  machines  the  steal-percentage  is  shown  (`steal'),  reflecting  the
            percentage of cpu time stolen by other virtual machines running on the same hardware.
            For  physical  machines hosting one or more virtual machines, the guest-percentage is
            shown (`guest'), reflecting the percentage of cpu time used by the virtual  machines.
            Notice that this percentage overlaps the user-percentage.

            In  case  of frequency-scaling, all previously mentioned CPU-percentages are relative
            to the used scaling of the CPU during the interval.  If a CPU  has  been  active  for
            e.g. 50% in user mode during the interval while the frequency-scaling of that CPU was
            40%, only 20% of the full capacity of the CPU has been used in user mode.
            In case that the kernel module `cpufreq_stats' is active  (after  issueing  `modprobe
            cpufreq_stats'),  the  average  frequency (`avgf') and the average scaling percentage
            (`avgscal') is shown. Otherwise  the  current  frequency  (`curf')  and  the  current
            scaling percentage (`curscal') is shown at the moment that the sample is taken.

            If  the  screen-width does not allow all of these counters, only a relevant subset is
            shown.

       CPL  CPU load information.
            This line contains the load average figures reflecting the number of threads that are
            available  to  run  on a CPU (i.e. part of the runqueue) or that are waiting for disk
            I/O. These figures are averaged over 1 (`avg1'), 5 (`avg5') and 15 (`avg15') minutes.
            Furthermore the number of context switches (`csw'), the number of serviced interrupts
            (`intr') and the number of available CPUs are shown.

            If  the  screen-width does not allow all of these counters, only a relevant subset is
            shown.

       MEM  Memory occupation.
            This line contains the total amount of physical memory (`tot'), the amount of  memory
            which is currently free (`free'), the amount of memory in use as page cache including
            the total resident shared memory (`cache'), the amount  of  memory  within  the  page
            cache  that  has  to  be  flushed  to  disk  (`dirty'), the amount of memory used for
            filesystem meta data (`buff'), the amount of memory being  used  for  kernel  mallocs
            (`slab'),  the amount of slab memory that is reclaimable (`slrec'), the resident size
            of shared memory including tmpfs  (`shmem`),  the  resident  size  of  shared  memory
            (`shrss`) the amount of shared memory that is currently swapped (`shswp`), the amount
            of memory that is currently claimed by vmware's balloon driver (`vmbal`), the  amount
            of  memory  that  is  claimed  for  huge pages (`hptot`), and the amount of huge page
            memory that is really in use (`hpuse`).

            If the screen-width does not allow all of these counters, only a relevant  subset  is
            shown.

       SWP  Swap occupation and overcommit info.
            This  line  contains the total amount of swap space on disk (`tot') and the amount of
            free swap space (`free').
            Furthermore the committed virtual memory space (`vmcom') and the maximum limit of the
            committed  space  (`vmlim', which is by default swap size plus 50% of memory size) is
            shown.  The committed space is the reserved virtual  space  for  all  allocations  of
            private  memory  space  for processes. The kernel only verifies whether the committed
            space   exceeds   the   limit   if   strict   overcommit   handling   is   configured
            (vm.overcommit_memory is 2).

       PAG  Paging frequency.
            This  line  contains  the  number of scanned pages (`scan') due to the fact that free
            memory drops below a particular threshold and the number times that the kernel  tries
            to reclaim pages due to an urgent need (`stall').
            Also  the  number  of  memory  pages the system read from swap space (`swin') and the
            number of memory pages the system wrote to swap space (`swout') are shown.

       LVM/MDD/DSK
            Logical volume/multiple device/disk utilization.
            Per active unit one line is produced, sorted on unit activity.  Such line  shows  the
            name  (e.g.  VolGroup00-lvtmp  for a logical volume or sda for a hard disk), the busy
            percentage i.e. the portion  of  time  that  the  unit  was  busy  handling  requests
            (`busy'),  the  number of read requests issued (`read'), the number of write requests
            issued (`write'), the number of KiBytes per read (`KiB/r'), the number of KiBytes per
            write (`KiB/w'), the number of MiBytes per second throughput for reads (`MBr/s'), the
            number of MiBytes per second throughput for writes (`MBw/s'), the average queue depth
            (`avq') and the average number of milliseconds needed by a request (`avio') for seek,
            latency and data transfer.
            If the screen-width does not allow all of these counters, only a relevant  subset  is
            shown.

            The number of lines showing the units can be limited per class (LVM, MDD or DSK) with
            the 'l' key or statically (see separate man-page of atoprc).  By specifying the value
            0 for a particular class, no lines will be shown any more for that class.

       NFM  Network Filesystem (NFS) mount at the client side.
            For  each  NFS-mounted  filesystem,  a line is shown that contains the mounted server
            directory, the name of the server (`srv'), the total number of bytes physically  read
            from  the  server  (`read')  and  the total number of bytes physically written to the
            server (`write').  Data transfer is subdivided in the number of bytes read via normal
            read()  system  calls (`nread'), the number of bytes written via normal read() system
            calls (`nwrit'), the number of bytes read via direct I/O  (`dread'),  the  number  of
            bytes  written  via  direct I/O (`dwrit'), the number of bytes read via memory mapped
            I/O pages (`mread'), and the number of bytes written  via  memory  mapped  I/O  pages
            (`mwrit').

       NFC  Network Filesystem (NFS) client side counters.
            This  line  contains  the  number of RPC calls issues by local processes (`rpc'), the
            number of read RPC calls (`read`) and write RPC calls (`rpwrite') issued to  the  NFS
            server,  the  number  of  RPC calls being retransmitted (`retxmit') and the number of
            authorization refreshes (`autref').

       NFS  Network Filesystem (NFS) server side counters.
            This line contains the number of RPC calls received from  NFS  clients  (`rpc'),  the
            number  of  read RPC calls received (`cread`), the number of write RPC calls received
            (`cwrit'), the number of network requests handled via TCP (`nettcp'), the  number  of
            network  requests handled via UDP (`netudp'), the number of Megabytes/second returned
            to read requests by clients (`MBcr/s`), the  number  of  Megabytes/second  passed  in
            write  requests by clients (`MBcw/s`), the number of reply cache hits (`rchits'), the
            number of  reply  cache  misses  (`rcmiss')  and  the  number  of  uncached  requests
            (`rcnoca').  Furthermore some error counters indicating the number of requests with a
            bad format (`badfmt') or a bad authorization (`badaut'), and a counter indicating the
            number  of  bad  clients  (`badcln').   and  the  number  of  authorization refreshes
            (`autref').

       NET  Network utilization (TCP/IP).
            One line is shown for activity of the transport layer (TCP and UDP), one line for the
            IP layer and one line per active interface.
            For  the  transport  layer,  counters are shown concerning the number of received TCP
            segments including those received in error (`tcpi'), the number  of  transmitted  TCP
            segments excluding those containing only retransmitted octets (`tcpo'), the number of
            UDP datagrams received (`udpi'), the number of UDP  datagrams  transmitted  (`udpo'),
            the  number of active TCP opens (`tcpao'), the number of passive TCP opens (`tcppo'),
            the number of TCP output retransmissions (`tcprs'), the number of  TCP  input  errors
            (`tcpie'),  the  number  of  TCP  output resets (`tcpor'), the number of UDP no ports
            (`udpnp'), and the number of UDP input errors (`udpie').
            If the screen-width does not allow all of these counters, only a relevant  subset  is
            shown.
            These counters are related to IPv4 and IPv6 combined.

            For  the  IP layer, counters are shown concerning the number of IP datagrams received
            from interfaces, including  those  received  in  error  (`ipi'),  the  number  of  IP
            datagrams  that  local  higher-layer  protocols offered for transmission (`ipo'), the
            number of received IP datagrams which were forwarded to other  interfaces  (`ipfrw'),
            the  number  of  IP  datagrams  which  were delivered to local higher-layer protocols
            (`deliv'), the number of  received  ICMP  datagrams  (`icmpi'),  and  the  number  of
            transmitted ICMP datagrams (`icmpo').
            If  the  screen-width does not allow all of these counters, only a relevant subset is
            shown.
            These counters are related to IPv4 and IPv6 combined.

            For every active network interface  one  line  is  shown,  sorted  on  the  interface
            activity.   Such  line shows the name of the interface and its busy percentage in the
            first column.  The busy percentage for half duplex is  determined  by  comparing  the
            interface speed with the number of bits transmitted and received per second; for full
            duplex the interface speed is compared with the highest of either the transmitted  or
            the  received  bits.   When  the  interface speed can not be determined (e.g. for the
            loopback interface), `---' is shown instead of the percentage.
            Furthermore the number of  received  packets  (`pcki'),  the  number  of  transmitted
            packets  (`pcko'),  the  line  speed of the interface (`sp'), the effective amount of
            bits received per second (`si'), the effective amount of bits transmitted per  second
            (`so'),  the  number of collisions (`coll'), the number of received multicast packets
            (`mlti'), the number of errors while receiving  a  packet  (`erri'),  the  number  of
            errors  while  transmitting a packet (`erro'), the number of received packets dropped
            (`drpi'), and the number of transmitted packets dropped (`drpo').
            If the screen-width does not allow all of these counters, only a relevant  subset  is
            shown.
            The number of lines showing the network interfaces can be limited.

OUTPUT DESCRIPTION - PROCESS LEVEL

       Following  the  system  level information, the processes are shown from which the resource
       utilization has changed during the last interval. These processes might have used cpu time
       or issued disk or network requests. However a process is also shown if part of it has been
       paged out due to lack of memory (while the process itself was in sleep state).

       Per process the following fields may be shown (in alphabetical order),  depending  on  the
       current  output mode as described in the section INTERACTIVE COMMANDS and depending on the
       current width of your window:

       AVGRSZ   The average size of one read-action on disk.

       AVGWSZ   The average size of one write-action on disk.

       BANDWI   Total bandwidth for received TCP and UDP packets consumed by this process  (bits-
                per-second).   This  value can be compared with the value `si' on interface level
                (used bandwidth per interface).
                This information will only be shown when the kernel module `netatop' is loaded.

       BANDWO   Total bandwidth for sent TCP and UDP packets consumed by this process  (bits-per-
                second).  This value can be compared with the value `so' on interface level (used
                bandwidth per interface).
                This information will only be shown when the kernel module `netatop' is loaded.

       CID      Container ID (Docker) of 12 hexadecimal digits, referring  to  the  container  in
                which  the process/thread is running.  If a process has been started and finished
                during the last interval, a `?' is shown because the container ID is not part  of
                the standard process accounting record.

       CMD      The  name  of  the  process.   This name can be surrounded by "less/greater than"
                signs (`<name>') which means that  the  process  has  finished  during  the  last
                interval.
                Behind the abbreviation `CMD' in the header line, the current page number and the
                total number of pages of the process/thread list are shown.

       COMMAND-LINE
                The full command line of the process (including arguments). If the length of  the
                command  line exceeds the length of the screen line, the arrow keys -> and <- can
                be used for horizontal scroll.
                Behind the verb `COMMAND-LINE' in the header line, the current  page  number  and
                the total number of pages of the process/thread list are shown.

       CPU      The  occupation  percentage of this process related to the available capacity for
                this resource on system level.

       CPUNR    The identification of the CPU the (main) thread is running  on  or  has  recently
                been running on.

       CTID     Container  ID  (OpenVZ).   If  a process has been started and finished during the
                last interval, a `?' is shown because  the  container  ID  is  not  part  of  the
                standard process accounting record.

       DSK      The  occupation  percentage  of  this  process  related to the total load that is
                produced by all processes (i.e. total disk accesses by all processes  during  the
                last interval).
                This  information is shown when per process "storage accounting" is active in the
                kernel.

       EGID     Effective group-id under which this process executes.

       ENDATE   Date that the process has been finished. If the process is  still  running,  this
                field shows `active'.

       ENTIME   Time  that  the  process has been finished. If the process is still running, this
                field shows `active'.

       ENVID    Virtual environment identified (OpenVZ only).

       EUID     Effective user-id under which this process executes.

       EXC      The exit code of a terminated process (second position of column `ST'  is  E)  or
                the fatal signal number (second position of column `ST' is S or C).

       FSGID    Filesystem group-id under which this process executes.

       FSUID    Filesystem user-id under which this process executes.

       MAJFLT   The  number  of  page  faults  issued  by  this  process that have been solved by
                creating/loading the requested memory page.

       MEM      The occupation percentage of this process related to the available  capacity  for
                this resource on system level.

       MINFLT   The  number  of  page  faults  issued  by  this  process that have been solved by
                reclaiming the requested memory page from the free list of pages.

       NET      The occupation percentage of this process related  to  the  total  load  that  is
                produced  by  all  processes  (i.e.  consumed  network bandwidth of all processes
                during the last interval).
                This information will only be shown when kernel module `netatop' is loaded.

       NICE     The more or less static priority that can be given to a process on a  scale  from
                -20 (high priority) to +19 (low priority).

       NPROCS   The  number  of  active  and  terminated  processes  accumulated for this user or
                program.

       PID      Process-id.  If a process has been started and finished during the last interval,
                a  `?'  is  shown  because  the  process-id  is  not part of the standard process
                accounting record.

       POLI     The policies 'norm' (normal, which is SCHED_OTHER),  'btch'  (batch)  and  'idle'
                refer to timesharing processes.  The policies 'fifo' (SCHED_FIFO) and 'rr' (round
                robin, which is SCHED_RR) refer to realtime processes.

       PPID     Parent process-id.  If a process has been started and finished  during  the  last
                interval,  value  0  is  shown  because  the parent process-id is not part of the
                standard process accounting record.

       PRI      The process' priority ranges from 0 (highest priority) to 139 (lowest  priority).
                Priority  0  to 99 are used for realtime processes (fixed priority independent of
                their behavior) and priority 100  to  139  for  timesharing  processes  (variable
                priority depending on their recent CPU consumption and the nice value).

       PSIZE    The proportional memory size of this process (or user).
                Every process shares resident memory with other processes. E.g. when a particular
                program is started several times, the code pages (text) are only loaded  once  in
                memory  and  shared  by  all  incarnations.  Also the code of shared libraries is
                shared by all processes using that shared library, as well as shared  memory  and
                memory-mapped files.  For the PSIZE calculation of a process, the resident memory
                of a process that is shared with other processes is  divided  by  the  number  of
                sharers.   This means, that every process is accounted for a proportional part of
                that memory. Accumulating the PSIZE values of all processes in the system gives a
                reliable impression of the total resident memory consumed by all processes.
                Since  gathering  of  all  values  that  are  needed  to calculate the PSIZE is a
                relatively time-consuming task, the 'R' key (or  '-R'  flag)  should  be  active.
                Gathering  these  values  also  requires  superuser privileges (otherwise '?K' is
                shown in the output).
                If a process has finished during the last interval, no value is shown  since  the
                proportional memory size is not part of the standard process accounting record.

       RDDSK    When the kernel maintains standard io statistics (>= 2.6.20):
                The  read data transfer issued physically on disk (so reading from the disk cache
                is not accounted for).
                Unfortunately, the kernel aggregates the data tranfer of a process  to  the  data
                transfer  of  its parent process when terminating, so you might see transfers for
                (parent) processes like cron, bash or init, that are not really issued by them.

       RGID     The real group-id under which the process executes.

       RGROW    The amount of resident  memory  that  the  process  has  grown  during  the  last
                interval. A resident growth can be caused by touching memory pages which were not
                physically created/loaded before (load-on-demand).  Note that a  resident  growth
                can  also  be  negative e.g. when part of the process is paged out due to lack of
                memory or when the process frees dynamically allocated  memory.   For  a  process
                which  started  during  the last interval, the resident growth reflects the total
                resident size of the process at that moment.
                If a process has finished during the last  interval,  no  value  is  shown  since
                resident memory occupation is not part of the standard process accounting record.

       RNET     The  number  of  TCP- and UDP packets received by this process.  This information
                will only be shown when kernel module `netatop' is installed.
                If a process has finished during the last  interval,  no  value  is  shown  since
                network counters are not part of the standard process accounting record.

       RSIZE    The  total resident memory usage consumed by this process (or user).  Notice that
                the RSIZE of a process includes all resident memory used by that process, even if
                certain memory parts are shared with other processes (see also the explanation of
                PSIZE).
                If a process has finished during the last  interval,  no  value  is  shown  since
                resident memory occupation is not part of the standard process accounting record.

       RTPR     Realtime priority according the POSIX standard.  Value can be 0 for a timesharing
                process (policy 'norm', 'btch' or 'idle') or  ranges  from  1  (lowest)  till  99
                (highest) for a realtime process (policy 'rr' or 'fifo').

       RUID     The real user-id under which the process executes.

       S        The  current state of the (main) thread: `R' for running (currently processing or
                in the runqueue), `S' for sleeping interruptible (wait for an  event  to  occur),
                `D'  for  sleeping  non-interruptible, `Z' for zombie (waiting to be synchronized
                with its parent  process),  `T'  for  stopped  (suspended  or  traced),  `W'  for
                swapping,  and  `E'  (exit)  for  processes  which  have finished during the last
                interval.

       SGID     The saved group-id of the process.

       SNET     The number of TCP and UDP packets transmitted by this process.  This  information
                will only be shown when the kernel module `netatop' is loaded.

       ST       The status of a process.
                The  first  position  indicates  if  the process has been started during the last
                interval (the value N means 'new process').

                The second position indicates if the process has been finished  during  the  last
                interval.
                The  value  E  means  'exit'  on  the  process'  own initiative; the exit code is
                displayed in the column `EXC'.
                The value S means that the process has been terminated unvoluntarily by a signal;
                the signal number is displayed in the in the column `EXC'.
                The value C means that the process has been terminated unvoluntarily by a signal,
                producing a core dump in its current directory; the signal number is displayed in
                the column `EXC'.

       STDATE   The start date of the process.

       STTIME   The start time of the process.

       SUID     The saved user-id of the process.

       SWAPSZ   The swap space consumed by this process (or user).

       SYSCPU   CPU time consumption of this process in system mode (kernel mode), usually due to
                system call handling.

       TCPRASZ  The average size of a received TCP buffer in bytes.  This information  will  only
                be shown when the kernel module `netatop' is loaded.

       TCPRCV   The  number of TCP packets received for this process.  This information will only
                be shown when the kernel module `netatop' is loaded.

       TCPSASZ  The average size of a transmitted TCP buffer in  bytes.   This  information  will
                only be shown when the kernel module `netatop' is loaded.

       TCPSND   The  number  of  TCP packets transmitted for this process.  This information will
                only be shown when the kernel module `netatop' is loaded.

       THR      Total number of threads within this process.  All related threads  are  contained
                in a thread group, represented by atop as one line or as a separate line when the
                'y' key (or -y flag) is active.

                On Linux 2.4 systems it is hardly  possible  to  determine  which  threads  (i.e.
                processes)  are related to the same thread group.  Every thread is represented by
                atop as a separate line.

       TID      Thread-id.  All threads within a process  run  with  the  same  PID  but  with  a
                different  TID.  This  value  is  shown  for individual threads in multi-threaded
                processes (when using the key 'y').

       TRUN     Number of threads within this process that are in the state 'running' (R).

       TSLPI    Number of threads within this  process  that  are  in  the  state  'interruptible
                sleeping' (S).

       TSLPU    Number  of  threads  within  this  process that are in the state 'uninterruptible
                sleeping' (D).

       UDPRASZ  The average size of a received UDP packet in bytes.  This information  will  only
                be shown when the kernel module `netatop' is loaded.

       UDPRCV   The  number  of UDP packets received by this process.  This information will only
                be shown when the kernel module `netatop' is loaded.

       UDPSASZ  The average size of a transmitted UDP packets in bytes.   This  information  will
                only be shown when the kernel module `netatop' is loaded.

       UDPSND   The  number  of  UDP  packets transmitted by this process.  This information will
                only be shown when the kernel module `netatop' is loaded.

       USRCPU   CPU time consumption of this process in user mode,  due  to  processing  the  own
                program text.

       VDATA    The  virtual memory size of the private data used by this process (including heap
                and shared library data).

       VGROW    The amount of virtual memory that the process has grown during the last interval.
                A  virtual growth can be caused by e.g. issueing a malloc() or attaching a shared
                memory segment. Note that a virtual growth can also be negative by e.g.  issueing
                a  free()  or  detaching  a  shared  memory segment.  For a process which started
                during the last interval, the virtual growth reflects the total virtual  size  of
                the process at that moment.
                If  a  process  has  finished  during  the last interval, no value is shown since
                virtual memory occupation is not part of the standard process accounting record.

       VPID     Virtual process-id (within an OpenVZ container).  If a process has  been  started
                and  finished  during  the  last  interval,  a  `?'  is shown because the virtual
                process-id is not part of the standard process accounting record.

       VSIZE    The total virtual memory usage consumed by this process (or user).
                If a process has finished during the last  interval,  no  value  is  shown  since
                virtual memory occupation is not part of the standard process accounting record.

       VSLIBS   The virtual memory size of the (shared) text of all shared libraries used by this
                process.

       VSTACK   The virtual memory size of the (private) stack used by this process

       VSTEXT   The virtual memory size of the (shared) text of the executable program.

       WRDSK    When the kernel maintains standard io statistics (>= 2.6.20):
                The write data transfer issued physically on disk (so writing to the  disk  cache
                is  not  accounted  for).  This counter is maintained for the application process
                that writes its data  to  the  cache  (assuming  that  this  data  is  physically
                transferred  to  disk  later on). Notice that disk I/O needed for swapping is not
                taken into account.
                Unfortunately, the kernel aggregates the data tranfer of a process  to  the  data
                transfer  of  its parent process when terminating, so you might see transfers for
                (parent) processes like cron, bash or init, that are not really issued by them.

       WCANCL   When the kernel maintains standard io statistics (>= 2.6.20):
                The write data transfer previously accounted for this process or another  process
                that  has  been  cancelled.  Suppose that a process writes new data to a file and
                that data is removed again before the cache buffers have been  flushed  to  disk.
                Then the original process shows the written data as WRDSK, while the process that
                removes/truncates the file shows the unflushed removed data as WCANCL.

PARSEABLE OUTPUT

       With the flag -P followed by a list of one or  more  labels  (comma-separated),  parseable
       output  is  produced  for  each sample.  The labels that can be specified for system-level
       statistics correspond to the labels (first verb of each line) that can  be  found  in  the
       interactive  output:  "CPU",  "cpu" "CPL" "MEM", "SWP", "PAG", "LVM", "MDD", "DSK", "NFM",
       "NFC", "NFS" and "NET".
       For process-level statistics special labels are introduced: "PRG" (general), "PRC"  (cpu),
       "PRM"  (memory),  "PRD" (disk, only if "storage accounting" is active) and "PRN" (network,
       only if the kernel module 'netatop' has been installed).
       With the label "ALL", all system and process level statistics are shown.

       For every interval all requested lines  are  shown  whereafter  atop  shows  a  line  just
       containing  the  label  "SEP"  as  a  separator  before  the lines for the next sample are
       generated.
       When a sample contains the values since boot, atop shows a line just containing the  label
       "RESET" before the lines for this sample are generated.

       The  first  part of each output-line consists of the following six fields: label (the name
       of the label), host (the name of this machine), epoch (the time of this interval as number
       of  seconds since 1-1-1970), date (date of this interval in format YYYY/MM/DD), time (time
       of this interval in format HH:MM:SS), and interval (number of  seconds  elapsed  for  this
       interval).

       The subsequent fields of each output-line depend on the label:

       CPU      Subsequent  fields:  total  number  of  clock-ticks  per second for this machine,
                number of processors, consumption for all  CPUs  in  system  mode  (clock-ticks),
                consumption  for all CPUs in user mode (clock-ticks), consumption for all CPUs in
                user mode for niced processes (clock-ticks), consumption for  all  CPUs  in  idle
                mode  (clock-ticks),  consumption  for  all  CPUs  in  wait  mode  (clock-ticks),
                consumption for all CPUs in irq mode (clock-ticks), consumption for all  CPUs  in
                softirq mode (clock-ticks), consumption for all CPUs in steal mode (clock-ticks),
                consumption for all CPUs in  guest  mode  (clock-ticks)  overlapping  user  mode,
                frequency of all CPUs and frequency percentage of all CPUs.

       cpu      Subsequent  fields:  total  number  of  clock-ticks  per second for this machine,
                processor-number,  consumption  for  this  CPU  in  system  mode   (clock-ticks),
                consumption  for this CPU in user mode (clock-ticks), consumption for this CPU in
                user mode for niced processes (clock-ticks), consumption for  this  CPU  in  idle
                mode  (clock-ticks),  consumption  for  this  CPU  in  wait  mode  (clock-ticks),
                consumption for this CPU in irq mode (clock-ticks), consumption for this  CPU  in
                softirq mode (clock-ticks), consumption for this CPU in steal mode (clock-ticks),
                consumption for this CPU in  guest  mode  (clock-ticks)  overlapping  user  mode,
                frequency of this CPU and frequency percentage of this CPU.

       CPL      Subsequent  fields:  number  of  processors,  load  average for last minute, load
                average for last five minutes, load average for last fifteen minutes,  number  of
                context-switches, and number of device interrupts.

       MEM      Subsequent fields: page size for this machine (in bytes), size of physical memory
                (pages), size of free memory (pages), size of page cache (pages), size of  buffer
                cache  (pages),  size  of slab (pages), dirty pages in cache (pages), reclaimable
                part of slab (pages), total size of vmware's balloon pages (pages), total size of
                shared  memory  (pages),  size of resident shared memory (pages), size of swapped
                shared memory (pages), huge page size (in bytes), total size of huge pages  (huge
                pages), and size of free huge pages (huge pages).

       SWP      Subsequent  fields:  page size for this machine (in bytes), size of swap (pages),
                size of free swap (pages), 0 (future use), size of committed space  (pages),  and
                limit for committed space (pages).

       PAG      Subsequent  fields:  page size for this machine (in bytes), number of page scans,
                number of allocstalls, 0 (future use), number of swapins, and number of swapouts.

       LVM/MDD/DSK
                For every logical volume/multiple device/hard disk one line is shown.
                Subsequent fields: name, number of milliseconds spent for I/O,  number  of  reads
                issued,  number  of  sectors  transferred for reads, number of writes issued, and
                number of sectors transferred for write.

       NFM      Subsequent fields: mounted NFS filesystem, total  number  of  bytes  read,  total
                number  of  bytes written, number of bytes read by normal system calls, number of
                bytes written by normal system calls, number of bytes read by direct I/O,  number
                of  bytes  written  by direct I/O, number of pages read by memory-mapped I/O, and
                number of pages written by memory-mapped I/O.

       NFC      Subsequent fields: number of transmitted RPCs, number of transmitted  read  RPCs,
                number  of  transmitted  write RPCs, number of RPC retransmissions, and number of
                authorization refreshes.

       NFS      Subsequent fields: number of handled RPCs, number of received read  RPCs,  number
                of  received write RPCs, number of bytes read by clients, number of bytes written
                by  clients,  number  of  RPCs  with  bad  format,  number  of  RPCs   with   bad
                authorization,  number  of  RPCs from bad client, total number of handled network
                requests, number of handled network requests via TCP, number of  handled  network
                requests  via  UDP,  number  of  handled TCP connections, number of hits on reply
                cache, number of misses on reply cache, and number of uncached requests.

       NET      First one line is produced for the upper layers of the TCP/IP stack.
                Subsequent fields: the verb "upper", number of packets received by TCP, number of
                packets  transmitted by TCP, number of packets received by UDP, number of packets
                transmitted by  UDP,  number  of  packets  received  by  IP,  number  of  packets
                transmitted by IP, number of packets delivered to higher layers by IP, and number
                of packets forwarded by IP.

                Next one line is shown for every interface.
                Subsequent fields: name of the interface,  number  of  packets  received  by  the
                interface,  number  of  bytes  received  by  the  interface,  number  of  packets
                transmitted by the interface, number  of  bytes  transmitted  by  the  interface,
                interface speed, and duplex mode (0=half, 1=full).

       PRG      For every process one line is shown.
                Subsequent  fields: PID (unique ID of task), name (between brackets), state, real
                uid, real gid, TGID (group number of  related  tasks/threads),  total  number  of
                threads,  exit  code,  start  time (epoch), full command line (between brackets),
                PPID, number of threads in state  'running'  (R),  number  of  threads  in  state
                'interruptible  sleeping'  (S),  number  of  threads  in  state  'uninterruptible
                sleeping' (D), effective uid, effective gid, saved  uid,  saved  gid,  filesystem
                uid,  filesystem gid, elapsed time (hertz), is_process (y/n), OpenVZ  virtual pid
                (VPID), OpenVZ container id (CTID) and Docker container id (CID).

       PRC      For every process one line is shown.
                Subsequent fields: PID, name (between brackets), state, total  number  of  clock-
                ticks  per  second  for  this machine, CPU-consumption in user mode (clockticks),
                CPU-consumption in system  mode  (clockticks),  nice  value,  priority,  realtime
                priority,  scheduling  policy,  current CPU, sleep average, TGID (group number of
                related tasks/threads) and is_process (y/n).

       PRM      For every process one line is shown.
                Subsequent fields: PID, name  (between  brackets),  state,  page  size  for  this
                machine  (in bytes), virtual memory size (Kbytes), resident memory size (Kbytes),
                shared text memory size (Kbytes), virtual memory growth (Kbytes), resident memory
                growth  (Kbytes),  number  of  minor  page  faults,  number of major page faults,
                virtual library exec size (Kbytes), virtual data  size  (Kbytes),  virtual  stack
                size   (Kbytes),  swap  space  used  (Kbytes),  TGID  (group  number  of  related
                tasks/threads), is_process (y/n) and proportional set size  (Kbytes)  if  in  'R'
                option is specified.

       PRD      For every process one line is shown.
                Subsequent  fields:  PID,  name (between brackets), state, obsoleted kernel patch
                installed ('n'), standard io statistics used ('y' or 'n'),  number  of  reads  on
                disk,  cumulative  number  of  sectors read, number of writes on disk, cumulative
                number of sectors written, cancelled  number  of  written  sectors,  TGID  (group
                number of related tasks/threads) and is_process (y/n).
                If  the  standard  I/O statistics (>= 2.6.20) are not used, the disk I/O counters
                per process are not relevant.  The counters 'number of reads on disk' and 'number
                of writes on disk' are obsoleted anyhow.

       PRN      For every process one line is shown.
                Subsequent  fields:  PID, name (between brackets), state, kernel module 'netatop'
                loaded ('y' or 'n'), number of TCP-packets transmitted, cumulative size  of  TCP-
                packets  transmitted,  number  of  TCP-packets  received, cumulative size of TCP-
                packets received, number of UDP-packets  transmitted,  cumulative  size  of  UDP-
                packets  transmitted,  number  of  UDP-packets  received, cumulative size of UDP-
                packets transmitted, number of raw  packets  transmitted  (obsolete,  always  0),
                number  of  raw  packets  received  (obsolete,  always  0), TGID (group number of
                related tasks/threads) and is_process (y/n).
                If the kernel module is not active, the network I/O counters per process are  not
                relevant.

EXAMPLES

       To monitor the current system load interactively with an interval of 5 seconds:

         atop 5

       To monitor the system load and write it to a file (in plain ASCII) with an interval of one
       minute during half an hour with active processes sorted on memory consumption:

         atop -M 60 30 > /log/atop.mem

       Store information about the system and process activity in binary  compressed  form  to  a
       file with an interval of ten minutes during an hour:

         atop -w /tmp/atop.raw 600 6

       View the contents of this file interactively:

         atop -r /tmp/atop.raw

       View the processor and disk utilization of this file in parseable format:

         atop -PCPU,DSK -r /tmp/atop.raw

       View the contents of today's standard logfile interactively:

         atop -r

       View the contents of the standard logfile of the day before yesterday interactively:

         atop -r yy

       View  the  contents  of  the  standard  logfile  of  2014,  June  7  from 02:00 PM onwards
       interactively:

         atop -r 20140607 -b 14:00

FILES

       /run/pacct_shadow.d/
            Directory containing the process accounting shadow files that are used by  atop  when
            the atopacctd daemon is active.

       /var/cache/atop.d/atop.acct
            File in which the kernel writes the accounting records when atop itself has activated
            the process accounting mechanism.

       /etc/atoprc
            Configuration file containing system-wide default values.  See related man-page.

       ~/.atoprc
            Configuration file containing personal default values.  See related man-page.

       /var/log/atop/atop_YYYYMMDD
            Raw file, where YYYYMMDD are digits representing the current date.  This name is used
            by  the script atop.daily as default name for the output file, and by atop as default
            name for the input file when using the -r flag.
            All binary system and process level data in this file has been stored  in  compressed
            format.

       /run/netatop.log
            File  that  contains the netpertask structs containing the network counters of exited
            processes. These structs are written by the netatopd daemon and read  by  atop  after
            reading the standard process accounting records.

SEE ALSO

       atopsar(1), atoprc(5), atopacctd(8), netatop(4), netatopd(8), logrotate(8)
       http://www.atoptool.nl

AUTHOR

       Gerlof Langeveld (gerlof.langeveld@atoptool.nl)
       JC van Winkel