Provided by: pcp_6.0.3-1_amd64 bug

NAME

       pcp-atop - Advanced System and Process Monitor

SYNOPSIS

       Interactive Usage:

       pcp  [pcp options] atop [-aAcCdDfFgGmMnNopRsuvxyY1] [-L linelen] [-Plabel[,label]... [-Z]]
       [interval [samples]]

       Writing and reading PCP archive folios:

       pcp atop -w folio [-a] [-S] [interval [samples]]
       pcp atop -r folio [-AcCdDfFgGmMnNopRsuvxy1] [-b [yy-mm-dd] hh:mm] [-e yy-mm-dd] hh:mm] [-L
       linelen] [-Plabel[,label]... [-Z]] [interval [samples]]

DESCRIPTION

       The  program  pcp-atop  is  an  interactive  monitor  to view various aspects of load on a
       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.

       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 invoked via the pcp(1) command, the  PCPIntro(1)  options  -A/--align,  -a/--archive,
       -h/--host,    -O/--origin,    -S/--start,    -s/--samples,   -T/--finish,   -t/--interval,
       -v/--version, -z/--hostzone and -z/--timezone become indirectly available.   Additionally,
       the --hotproc option can be used to request the per-process PCP metrics be used instead of
       the default proc metrics from pmdaproc(1).

       When pcp-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 pcp-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 pcp-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 pcp-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  pcp-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 pcp-atop data in PCP archive format
       (see section PCP DATA STORAGE).

COLORS

       For the resource consumption on system level, pcp-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  pcp-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
       pcp-atoprc(5)).

       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 pcp-atoprc(5)).
       The default colors red and cyan can be modified in the configuration  file  as  well  (see
       separate man-page of pcp-atoprc(5)).

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

GPU STATISTICS GATHERING

       GPU statistics can be gathered by pmdanvidia(1) which is a separate data collection daemon
       process.  It gathers cumulative utilization counters of every Nvidia GPU in the system, as
       well as utilization counters of every process that uses a GPU.  When pcp-atop notices that
       the daemon is active, it reads these GPU utilization counters with every interval.

       Find a description about the utilization counters in the section OUTPUT DESCRIPTION.

INTERACTIVE COMMANDS

       When running pcp-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.
            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.

       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.

       X    Show cgroup v2 information.

            Per  process  the  following  fields are shown: process-id, the command name, and the
            cgroup path name (horizontally scrollable).

       e    Show GPU utilization.

            Per process at least the following fields are shown: process-id, range of GPU numbers
            on  which  the  process  currently runs, GPU busy percentage on all GPUs, memory busy
            percentage (i.e. read and write accesses on memory) on all GPUs, memory occupation at
            the  moment  of  the  sample,  average  memory  occupation during the sample, and GPU
            percentage.

            When the pmdanvidia daemon does not run with root privileges, the GPU busy percentage
            and the memory busy percentage are not available on process level.  In that case, the
            GPU percentage on process level reflects the GPU memory occupation instead of the GPU
            busy percentage (which is preferred).

       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 pcp-atoprc(5) 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.  Depending on the option 'Y' (sort threads),
            the threads per process will be sorted on the chosen sort criterium or not.
            Whether this key is active or not can be seen in the header line.

       Y    Sort the threads per process when combined with option 'y' (toggle).

       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  pmdabcc(1)  module  `netproc'  has been
            installed, the number of receive and send network calls 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  pmdabcc(1)  module  `netproc'  has  been
            installed, the number of receive and send network calls 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  pmdabcc(1)  module  `netproc'  has been
            installed, the number of receive and send network calls 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''.

       E    Sort the current list in the order of GPU utilization (preferred, but only applicable
            when  the  pmdanvidia  daemon  runs under root privileges) or the order of GPU memory
            occupation).  The one-but-last column changes to ``GPU''.

       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 pmdabcc(1) module `netproc' has
            been installed.

       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 very time-
            consuming task, so this key should only be active when analyzing the resident  memory
            consumption of processes.

       W    Get  the  WCHAN  per  thread (toggle).  Gathering of the WCHAN string per thread is a
            relatively time-consuming task, so this key should only be made active when analyzing
            the reason for threads to be in sleep state.

       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 pcp-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, pcp-atop will continue with the 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 pcp-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 an archive folio, this key can be used to show the  next
            sample from the folio.

       T    When  viewing  the  contents  of  an  archive folio, this key can be used to show the
            previous sample from the folio.

       b    When viewing the contents of an archive folio, this key can be  used  to  move  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  an  archive,  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.

       Q    Specify a comma-separated list of  process  state  characters.   From  now  on,  only
            processes  will  be shown that are in those specific process states.  Accepted states
            are: R (running), S (sleeping), D (disk sleep), T  (stopped),  t  (tracing  stop),  X
            (dead),  Z (zombie) and P (parked).  The system statistics are still system wide.  If
            the Enter-key is pressed without specifying a state, 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, pcp-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 pcp-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 pcp-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.

PCP 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), pcp-atop can store the system and process level statistics in the PCP archive format,
       as an archive folio (see mkaf(1)).
       All information about processes and threads is stored in the archive.
       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 pcp-atop should finish anyhow before midnight.

       A  PCP  archive  can  be  read and visualized again with the -r option.  The argument is a
       comma-separated list of names, each of which may be the base name of  an  archive  or  the
       name  of  a  directory  containing one or more archives.  If no argument is specified, the
       file $PCP_LOG_DIR/pmlogger/HOST/YYYYMMDD is opened for input (where  YYYYMMDD  are  digits
       representing  the current date, and HOST is the hostname of the machine being logged).  If
       a filename is specified in the format YYYYMMDD (representing any  valid  date),  the  file
       $PCP_LOG_DIR/pmlogger/HOST/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, pcp-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
       [YY-MM-DD] HH:MM, a certain time period within the archive can be selected.

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 pcp-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 pcp-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 field combined with the wait percentage.

            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 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 (`steal') shows 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
            (`guest') shows the percentage of cpu time used by the virtual machines.  Notice that
            this percentage overlaps the user-percentage!

            When PMC performance monitoring counters are supported by the CPU and the kernel (and
            pmdaperfevent(1) runs with root privileges), the number of instructions per CPU cycle
            (`ipc')  is  shown.   The  first sample always shows the value 'initial', because the
            counters are just activated at the moment that pcp-atop is started.
            When the CPU busy percentage is high and the IPC is less than 1.0, it is likely  that
            the  CPU is frequently waiting for memory access during instruction execution (larger
            CPU caches or faster memory might be helpful to improve performance).  When  the  CPU
            busy percentage is high and the IPC is greater than 1.0, it is likely that the CPU is
            instruction-bound (more/faster cores might be helpful to improve performance).
            Furthermore, per CPU the effective number of cycles (`cycl') is  shown.   This  value
            can  reach  the  current CPU frequency if such CPU is 100% busy.  When an idle CPU is
            halted, the number of effective cycles can be (considerably) lower than  the  current
            frequency.
            Notice  that  the average instructions per cycle and number of cycles is shown in the
            CPU line for all CPUs.
            See also: http://www.brendangregg.com/blog/2017-05-09/cpu-utilization-is-wrong.html

            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 issuing `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.
            Notice  that  average  values for frequency and scaling are shown in the CPU line for
            every CPU.
            Frequency scaling statistics are only gathered for systems with maximum 8 CPUs, since
            gathering of these values per CPU is very time consuming.

            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.

       GPU  GPU utilization (Nvidia).
            Read the section GPU STATISTICS GATHERING in this document to find the details  about
            the activation of the pmdanvidia daemon.

            In  the  first  column  of  every line, the bus-id (last nine characters) and the GPU
            number are shown.  The subsequent columns show the percentage of  time  that  one  or
            more  kernels  were  executing  on  the  GPU (`gpubusy'), the percentage of time that
            global (device)  memory  was  being  read  or  written  (`membusy'),  the  occupation
            percentage  of memory (`memocc'), the total memory (`total'), the memory being in use
            at the moment of the sample (`used'), the average memory  being  in  use  during  the
            sample  time (`usavg'), the number of processes being active on the GPU at the moment
            of the sample (`#proc'), and the type of GPU.

            If the screen-width does not allow all of these counters, only a relevant  subset  is
            shown.
            The number of lines showing the GPUs can be limited.

       MEM  Memory occupation (two lines).
            These lines contain 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 used for page tables (`pgtab'), the number of NUMA nodes
            in this system (`numnode'), the  amount  of  memory  that  is  currently  claimed  by
            vmware's  balloon driver (`vmbal'), the amount of memory that is currently claimed by
            the ARC (cache) of ZFSonlinux (`zfarc'), the amount of memory  that  is  claimed  for
            huge pages (`hptot'), the amount of huge page memory that is really in use (`hpuse'),
            the amount of memory that is used for TCP sockets (`tcps'), and the amount of  memory
            that is used for UDP sockets (`udps').

            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'),  the size of the swap cache (`swcac'), the total size of
            compressed storage in zswap (`zpool'), the total size of the compressed pages  stored
            in zswap (`zstor'), the total size of the memory used for KSM (`ksuse', i.e. shared),
            and the total size of the memory saved (deduped) by KSM (`kssav', i.e. sharing).
            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).

       NUM  Memory utilization per NUMA node (not shown for single NUMA node).
            This  line shows the total amount of physical memory of this node (`tot'), the amount
            of free memory (`free'), the amount of memory for cached file data (`file'), modified
            cached file data (`dirty'), recently used memory (`activ'), less recently used memory
            (`inact'), memory being used for kernel mallocs (`slab'), the amount of  slab  memory
            that  is  reclaimable  (`slrec'), shared memory including tmpfs (`shmem'), total huge
            pages (`hptot') and the fragmentation percentage (`frag').

       NUC  CPU utilization per NUMA node (not shown for single NUMA node).
            This line shows the utilization percentages of all CPUs related to  this  NUMA  node,
            categorized  for   system  mode  (`sys'),  user  mode  (`user'),  user mode for niced
            processes (`niced'), idle mode (`idle'), wait mode (`w' preceded by the node number),
            irq  mode  (`irq'),  softirq  mode  (`sirq'),  steal  mode  (`steal'), and guest mode
            (`guest') overlapping user mode.

       PAG  Paging frequency.
            This line contains the number of scanned pages (`scan') due to  the  fact  that  free
            memory  drops below a particular threshold, the number of times that the kernel tries
            to reclaim pages due to an urgent need (`stall'), the number of process stalls to run
            memory  compaction  to  allocate  huge  pages  (`compact'),  the number of NUMA pages
            migrated (`numamig'), and the total number of memory pages migrated successfully e.g.
            between NUMA nodes or for compaction (`migrate') are shown.
            Also  the  number  of  memory  pages the system read from block devices (`pgin'), the
            number of memory pages the system wrote to block devices  (`pgout'),  the  number  of
            memory pages the system read from swap space (`swin'), the number of memory pages the
            system wrote  to  swap  space  (`swout'),  and  the  number  of  out-of-memory  kills
            (`oomkill').

       PSI  Pressure Stall Information.
            This  line  contains  percentages  about resource pressure related to CPU, memory and
            I/O. Certain percentages refer to 'some' meaning  that  some  processes/threads  were
            delayed due to resource overload. Other percentages refer to 'full' meaning a loss of
            overall throughput due to resource overload.
            The values `cpusome', `memsome', `memfull', `iosome' and `iofull' show  the  pressure
            percentage during the entire interval.
            The  values  `cs' (cpu some), `ms' (memory some), `mf' (memory full), `is' (I/O some)
            and `if' (I/O full) each  show  three  percentages  separated  by  slashes:  pressure
            percentage over the last 10, 60 and 300 seconds.

       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
            percentage  of  elapsed  time  during  which  I/O  requests were issued to the device
            (`busy') (note that for devices serving requests in parallel, such  as  RAID  arrays,
            SSD  and  NVMe, this number does not reflect their performance limits), the number of
            read requests issued (`read'), the number of write  requests  issued  (`write'),  the
            number  of  discard  requests  issued  (`discrd') if supported by kernel version, the
            number of KiBytes per read (`KiB/r'), the number of KiBytes per write (`KiB/w'),  the
            number of KiBytes per discard (`KiB/d') if supported by kernel version, the number of
            MiBytes per second throughput for reads (`MBr/s'), the number of MiBytes  per  second
            throughput  for  writes  (`MBw/s'),  requests  issued  to  the  device driver but not
            completed (`inflt'), 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 pcp-atoprc(5)).  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  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 network requests handled via TCP (`nettcp'), the number of
            network requests  handled  via  UDP  (`netudp'),  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').

       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.

       IFB  Infiniband utilization.
            For  every  active  Infiniband port one line is shown, sorted on activity.  Such line
            shows the name of the port and its busy percentage in the  first  column.   The  busy
            percentage  is  determined  by  taking  the  highest of either the transmitted or the
            received bits during the interval, multiplying that value by the number of lanes  and
            comparing it against the maximum port speed.
            Furthermore  the  number of received packets divided by the number of lanes (`pcki'),
            the number of transmitted packets divided  by  the  number  of  lanes  (`pcko'),  the
            maximum  line  speed (`sp'), the effective amount of bits received per second (`si'),
            the effective amount of bits transmitted per second (`so'), and the number  of  lanes
            (`lanes').
            If  the  screen-width does not allow all of these counters, only a relevant subset is
            shown.
            The number of lines showing the Infiniband ports 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 pmdabcc(1) module `netproc' has been
                installed.

       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 pmdabcc(1) module `netproc' has been
                installed.

       BDELAY   Aggregated block I/O delay, i.e. time waiting for disk I/O.

       CGROUP   Path  name  of  the  cgroup (version 2) to which this process belongs.  This path
                name is relative to the cgroup root directory, which is usually `/sys/fs/cgroup'.

       CID      Container ID 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.

       GPU      When  the pmdanvidia daemon does not run with root privileges, the GPU percentage
                reflects the GPU memory occupation percentage (memory of all GPUs is 100%).
                When the pmdanvidia daemon runs with root privileges, the GPU percentage reflects
                the GPU busy percentage.

       GPUBUSY  Busy percentage on all GPUs (one GPU is 100%).
                When  the  pmdanvidia daemon does not run with root privileges, this value is not
                available.

       GPUNUMS  Comma-separated list of GPUs used by the process during the interval.   When  the
                comma-separated  list  exceeds  the  width  of the column, a hexadecimal value is
                shown.

       LOCKSZ   The virtual amount of memory being locked (i.e. non-swappable)  by  this  process
                (or user).

       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.

       MEMAVG   Average memory occupation during the interval on all used GPUs.

       MEMBUSY  Busy  percentage  of  memory on all GPUs (one GPU is 100%), i.e.  the time needed
                for read and write accesses on memory.
                When the pmdanvidia daemon does not run with root privileges, this value  is  not
                available.

       MEMNOW   Memory occupation at the moment of the sample on all used GPUs.

       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 the pmdabcc(1) module `netproc' has been
                installed.

       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.

       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.

       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 very
                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).

       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 transfer 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.

       RDELAY   Runqueue delay, i.e. time spent waiting on a runqueue.

       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.

       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).

       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.

       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 BCC PMDA is active and the `netproc' module is enabled.

       TCPRCV   The  number  of  tcp_recvmsg()/tcp_cleanup_rbuf()  calls from this process.  This
                information will only be shown when the BCC PMDA  is  active  and  the  `netproc'
                module is enabled.

       TCPSASZ  The  average  size  of  a  TCP buffer requested to be transmitted in bytes.  This
                information will only be shown when the BCC PMDA  is  active  and  the  `netproc'
                module is enabled.

       TCPSND   The  number of tcp_sendmsg() calls from this process.  This information will only
                be shown when the BCC PMDA is active and the `netproc' module is enabled.

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

       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 buffer in bytes.  This information  will  only
                be shown when the BCC PMDA is active and the `netproc' module is enabled.

       UDPRCV   The  number  of  udp_recvmsg()/skb_consume_udp()  calls  from this process.  This
                information will only be shown when the BCC PMDA  is  active  and  the  `netproc'
                module is enabled.

       UDPSASZ  The  average  size  of  a  UDP buffer requested to be transmitted in bytes.  This
                information will only be shown when the BCC PMDA  is  active  and  the  `netproc'
                module is enabled.

       UDPSND   The  number of udp_sendmsg() calls from this process.  This information will only
                be shown when the BCC PMDA is active and the `netproc' module is enabled.

       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. issuing a malloc() or attaching a shared
                memory segment. Note that a virtual growth can also be negative by e.g. issuing 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.

       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).

       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.

       WCHAN    Wait channel of thread in sleep state, i.e. the name of the  kernel  function  in
                which the thread has been put asleep.
                Since  determining  the  name string of the kernel function is a relatively time-
                consuming task, the 'W' key (or '-W' flag) should be active.

       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 transfer 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", "GPU", "MEM", "SWP", "PAG", "PSI", "LVM", "MDD",
       "DSK", "NFM", "NFC", "NFS", "NET", "IFB", "LLC", "NUM" and "NUC".
       For process-level statistics special labels are introduced: "PRG" (general), "PRC"  (cpu),
       "PRE" (GPU), "PRM" (memory), "PRD" (disk, only if "storage accounting" is active).
       With the label "ALL", all system and process level statistics are shown.

       The  command  and  command  line  in  the  parseable  output  might contain spaces and are
       therefore by default surrounded by parenthesis. However, since a space is  often  used  as
       separator  between the fields by parsing tools, with the additional flag -Z it is possible
       to exchange the spaces in the command (line) by underscores and omit the parenthesis.

       For every interval all requested lines are shown whereafter pcp-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, pcp-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 all CPUs, frequency percentage of all CPUs, instructions executed by
                all CPUs and cycles for all CPUs.

       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.

       GPU      Subsequent fields: GPU number, bus-id  string,  type  of  GPU  string,  GPU  busy
                percentage  during  last  second  (-1  if  not available), memory busy percentage
                during last second (-1 if not available), total memory size  (KiB),  used  memory
                (KiB)  at  this  moment,  number of samples taken during interval, cumulative GPU
                busy percentage during the interval (to be divided by the number of  samples  for
                the  average  busy  percentage,  -1  if  not  available),  cumulative memory busy
                percentage during the interval (to be divided by the number of  samples  for  the
                average  busy  percentage, -1 if not available), and cumulative memory occupation
                during the interval (to be divided by the  number  of  samples  for  the  average
                occupation).

       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),  size  of free huge pages (huge pages), size of ARC (cache) of ZFSonlinux
                (pages), size of sharing pages for KSM (pages), size  of  shared  pages  for  KSM
                (pages), size of memory used for TCP sockets (pages), size of memory used for UDP
                sockets (pages), and size of pagetables (pages).

       SWP      Subsequent fields: page size for this machine (in bytes), size of  swap  (pages),
                size  of  free  swap (pages), size of swap cache (pages), size of committed space
                (pages), limit for committed space (pages), size of the swap cache (pages),  size
                of compressed pages stored in zswap (pages), and total size of compressed pool in
                zswap (pages).

       PAG      Subsequent fields: page size for this machine (in bytes), number of  page  scans,
                number  of  allocstalls,  0  (future use), number of swapins, number of swapouts,
                number of oomkills (-1 when counter not present), number of process stalls to run
                memory compaction, number of pages successfully migrated in total, number of NUMA
                pages migrated, number of pages read from block  devices,  and  number  of  pages
                written to block devices.

       PSI      Subsequent  fields:  PSI  statistics  present  on  this system (n or y), CPU some
                avg10, CPU some avg60, CPU some avg300, CPU some accumulated microseconds  during
                interval,  memory  some avg10, memory some avg60, memory some avg300, memory some
                accumulated microseconds during interval, memory full avg10, memory  full  avg60,
                memory  full  avg300,  memory  full accumulated microseconds during interval, I/O
                some avg10, I/O some avg60, I/O some avg300, I/O  some  accumulated  microseconds
                during  interval,  I/O  full avg10, I/O full avg60, I/O full avg300, and I/O full
                accumulated microseconds during interval.

       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, number
                of  sectors  transferred  for  write,  number  of  discards  issued  (-1  if  not
                supported),  number  of  sectors  transferred  for  discards,  number of requests
                currently in flight (not yet completed), and the average queue  depth  while  the
                disk was busy.

       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, number  of
                packets  forwarded  by  IP, number of input errors (UDP), number of noport errors
                (UDP), number of active opens (TCP), number of passive  opens  (TCP),  number  of
                passive  opens  (TCP),  number  of  established connections at this moment (TCP),
                number of retransmitted segments (TCP), number of input errors (TCP), and  number
                of output resets (TCP).

                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).

       IFB      Subsequent fields: name of the  InfiniBand  interface,  port  number,  number  of
                lanes,   maximum   rate  (Mbps),  number  of  bytes  received,  number  of  bytes
                transmitted, number of packets received, and number of packets transmitted.

       NUM      Subsequent fields: NUMA node number, page size for this machine (in  bytes),  the
                fragmentation  percentage  of this node, size of physical memory (pages), size of
                free memory  (pages),  recently  (active)  used  memory  (pages),  less  recently
                (inactive)  used memory (pages), size of cached file data (pages), dirty pages in
                cache (pages), slab memory being used for kernel  mallocs  (pages),  slab  memory
                that  is  reclaimable  (pages),  shared memory including tmpfs (pages), and total
                huge pages (pages).

       NUC      Subsequent fields:  NUMA  node  number,  number  of  processors  for  this  node,
                consumption for node CPUs in system mode (clock-ticks), consumption for node CPUs
                in user mode (clock-ticks), consumption for node CPUs  in  user  mode  for  niced
                processes  (clock-ticks),  consumption  for node CPUs in idle mode (clock-ticks),
                consumption for node CPUs in wait mode (clock-ticks), consumption for  node  CPUs
                in  irq  mode  (clock-ticks),  consumption  for node CPUs in softirq mode (clock-
                ticks), consumption for node CPUs in steal mode  (clock-ticks),  and  consumption
                for node CPUs in guest mode (clock-ticks) overlapping user mode.

       PRG      For every process one line is shown.
                Subsequent  fields:  PID  (unique  ID  of  task),  name  (between  parenthesis or
                underscores for spaces), state, real uid, real gid, TGID (group number of related
                tasks/threads),  total  number  of  threads,  exit code (in case of fatal signal:
                signal number + 256), start time (epoch), full command line (between  parenthesis
                or  underscores  for  spaces),  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  of  terminated  process
                (hertz),  is_process  (y/n),  OpenVZ   virtual  pid  (VPID),  OpenVZ container id
                (CTID), Container id (CID), indication if the task is newly started  during  this
                interval  ('N'),  and cgroup v2 path name (between parenthesis or underscores for
                spaces).

       PRC      For every process one line is shown.
                Subsequent fields: PID, name (between parenthesis  or  underscores  for  spaces),
                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), is_process (y/n), runqueue
                delay  in  nanoseconds  for  this thread or for all threads (in case of process),
                wait channel of this thread (between  parenthesis  or  underscores  for  spaces),
                block I/O delay (clockticks).

       PRE      For every process one line is shown.
                Subsequent  fields:  PID,  name  (between parenthesis or underscores for spaces),
                process state, GPU state (A for active, E for exited, N for no GPU user),  number
                of  GPUs  used by this process, bitlist reflecting used GPUs, GPU busy percentage
                during interval, memory busy percentage during interval, memory occupation  (KiB)
                at  this moment cumulative memory occupation (KiB) during interval, and number of
                samples taken during interval.

       PRM      For every process one line is shown.
                Subsequent fields: PID, name (between parenthesis  or  underscores  for  spaces),
                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),  proportional  set  size
                (Kbytes)  if  in  'R'  option  is  specified  and  virtually  locked memory space
                (Kbytes).

       PRD      For every process one line is shown.
                Subsequent fields: PID, name (between parenthesis  or  underscores  for  spaces),
                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), obsoleted value ('n'), 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 parenthesis or underscores for spaces),
                state, pmdabcc(1) module `netproc' loaded ('y' or 'n'), number  of  tcp_sendmsg()
                calls,  cumulative  size  of  TCP  buffers requested to be transmitted, number of
                tcp_recvmsg()/tcp_cleanup_rbuf() calls, cumulative size of TCP buffers  received,
                number  of  udp_sendmsg()  calls,  cumulative size of UDP buffers requested to be
                transmitted, number of udp_recvmsg()/skb_consume_udp() calls, cumulative size  of
                UDP  buffers 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).

SIGNALS

       By sending the SIGUSR1 signal to pcp-atop a new sample will be forced, even if the current
       timer interval has not exceeded yet.  The behavior is similar to pressing the `t`  key  in
       an interactive session.

       By  sending  the SIGUSR2 signal to pcp-atop a final sample will be forced after which pcp-
       atop will terminate.

EXAMPLES

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

         pcp 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:

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

       Store  information  about  the  system and process activity in a PCP archive folio with an
       interval of ten minutes during an hour:

         pcp atop -w /tmp/pcp-atop 600 6

       View the contents of this file interactively:

         pcp atop -r /tmp/pcp-atop

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

         pcp atop -PCPU,DSK -r /tmp/pcp-atop.folio

       View the contents of today's standard logfile interactively:

         pcp atop -r

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

         pcp atop -r yy

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

         pcp atop -r 20140607 -b 14:00

NOTES

       pcp-atop  is  based  on  the  source code of the atop(1) command from https://atoptool.nl,
       maintained by Gerlof Langeveld (gerlof.langeveld@atoptool.nl), and aims to be command line
       and output compatible with it as much as possible.  Some features of that atop command are
       not available in pcp-atop.

       Some features of pcp-atop (such as reporting on the Apache HTTP  daemon,  Infiniband,  NFS
       client  mounts,  hardware  event  counts,  GPU  statistics  and  per-process  TCP  and UDP
       statistics) are only activated if the corresonding PCP metrics are available. Refer to the
       documentation   for  pmdaapache(1),  pmdainfiniband(1),  pmdanfsclient(1),  pmdanvidia(1),
       pmdaperfevent(1) and pmdabcc(1) for further details on activating these metrics.

       The semantics of the per-process network statistics  deviate  slightly  from  the  atop(1)
       tool:  instead of the number of TCP/UDP packets sent/received (which may be inaccurate due
       to     TCP     segmentation     offload),     pcp-atop     shows     the     number     of
       tcp_sendmsg()/udp_sendmsg()/etc. kernel calls per process.

FILES

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

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

PCP ENVIRONMENT

       Environment variables with the prefix PCP_ are used to parameterize the file and directory
       names used by PCP.  On each installation, the file /etc/pcp.conf contains the local values
       for  these  variables.   The  $PCP_CONF  variable  may  be  used to specify an alternative
       configuration file, as described in pcp.conf(5).

       For environment variables affecting PCP tools, see pmGetOptions(3).

SEE ALSO

       PCPIntro(1),  pcp(1),  pcp-atopsar(1),   pmdaapache(1),   pmdabcc(1),   pmdainfiniband(1),
       pmdanfsclient(1),  pmdanvidia(1), pmdaproc(1), mkaf(1), pmlogger(1), pmlogger_daily(1) and
       pcp-atoprc(5).