Provided by: atop_2.2.6-4_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).
       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.

       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.

       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''.

       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.

       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.
       By default only processes which have been active during the interval are stored in the raw
       file. When the flag -a is specified, all processes will be stored.
       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.

       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.  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  a  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),  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),  virtual  pid  and
                container id.

       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