atop

ATOP(1)                     General Commands Manual                    ATOP(1)



NAME
       atop - Advanced System & Process Monitor

SYNOPSIS
       Interactive Usage:

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

       Writing and reading raw logfiles:

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

GPU STATISTICS GATHERING
       GPU statistics can be gathered by atopgpud 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 atop notices that the daemon is
       active, it reads these GPU utilization counters with every interval.

       The atopgpud daemon is written in Python, so a Python interpreter
       should be installed on the target system. The Python code of the daemon
       is compatible with Python version 2 and version 3.  For the gathering
       of the statistics, the pynvml module is used by the daemon. Be sure
       that this module is installed on the target system before activating
       the daemon, by running the command as root pip (the command pip might
       be exchanged by pip3 in case of Python3):

         pip install nvidia-ml-py

       The atopgpud daemon is installed by default as part of the atop
       package, but it is not automatically enabled.  The daemon can be
       enabled and started now by running the following commands (as root):

         systemctl enable atopgpu
         systemctl start atopgpu

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

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

       g    Show generic output (default).

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

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

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

       m    Show memory related output.

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

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

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

       d    Show disk-related output.

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

       n    Show network related output.

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

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

       s    Show scheduling characteristics.

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

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

       v    Show various process characteristics.

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

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

       c    Show the command line of the process.

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

       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 atopgpud 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 atoprc for a detailed description.

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

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

       u    Show the process activity accumulated per user.

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

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

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

       j    Show the process activity accumulated per Docker container.

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

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

       E    Sort the current list in the order of GPU utilization (preferred,
            but only applicable when the atopgpud 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 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 (except when reading raw
            data from a named pipe).

       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 (except when reading raw data from a named pipe).

       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 (except when reading raw
            data from a named pipe).

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

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

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

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

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

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

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

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

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

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

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

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

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

       q    Quit the program.

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

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

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

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

       ^L   Redraw the screen.

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

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

       Every day at midnight atop is restarted to write compressed binary data
       to the file /var/log/atop/atop_YYYYMMDD with an interval of 10 minutes
       by default. The -R flag is passed by default to gather information
       about the proportional set size of every process.
       Furthermore all raw files are removed that are older than 28 days (by
       default).
       The mentioned default values can be overruled in the file
       /etc/default/atop that might contain other values for LOGOPTS (by
       default the -R flag), LOGINTERVAL (in seconds, by default 600),
       LOGGENERATIONS (in days, by default 28), and LOGPATH (directory in
       which logfiles are stored).

       Unfortunately, it is not always possible to keep the format of the raw
       files compatible in newer versions of atop especially when lots of new
       counters have to be maintained.  Therefore, the program atopconvert is
       installed to convert a raw file created by an older version of atop to
       a raw file that can be read by a newer version of atop (see the man
       page of atopconvert for more details).


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
            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 atop 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 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.
            Beware that reading the cycle counter in virtual machines (guests)
            might introduce performance delays. Therefore this metric is by
            default disabled in virtual machines. However, with the keyword
            'perfevents' in the atoprc file this metric can be explicitly set
            to 'enable' or 'disable' (see separate man-page of atoprc).
            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
            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.
            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 atopgpud 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.
            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.

       PSI  Pressure Stall Information.
            This line contains three percentages per category: average
            pressure percentage over the last 10, 60 and 300 seconds
            (separated by slashes).
            The categories are: CPU for 'some' (`cs'), memory for 'some'
            (`ms'), memory for 'full' (`mf'), I/O for 'some' (`is'), and I/O
            for 'full' (`if').

       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
            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 kernel module
                `netatop' is loaded.

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

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

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

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

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

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

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

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

       EGID     Effective group-id under which this process executes.

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

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

       ENVID    Virtual environment identified (OpenVZ only).

       EUID     Effective user-id under which this process executes.

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

       FSGID    Filesystem group-id under which this process executes.

       FSUID    Filesystem user-id under which this process executes.

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

       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 atopgpud 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 kernel module
                `netatop' is loaded.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

       SGID     The saved group-id of the process.

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

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

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

       STDATE   The start date of the process.

       STTIME   The start time of the process.

       SUID     The saved user-id of the process.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

PARSEABLE OUTPUT
       With the flag -P followed by a list of one or more labels (comma-
       separated), parseable output is produced for each sample.  The labels
       that can be specified for system-level statistics correspond to the
       labels (first verb of each line) that can be found in the interactive
       output: "CPU", "cpu", "CPL", "GPU", "MEM", "SWP", "PAG", "PSI", "LVM",
       "MDD", "DSK", "NFM", "NFC", "NFS", "NET" and "IFB".
       For process-level statistics special labels are introduced: "PRG"
       (general), "PRC" (cpu), "PRE" (GPU), "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, frequency
                percentage of all CPUs, instructions executed by all CPUs and
                cycles for 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, frequency
                percentage of this CPU, instructions executed by this CPU and
                cycles for 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.

       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),
                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.

       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, 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).

       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.

       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 (in
                case of fatal signal: signal number + 256), start time
                (epoch), full command line (between brackets), PPID, number of
                threads in state 'running' (R), number of threads in state
                'interruptible sleeping' (S), number of threads in state
                'uninterruptible sleeping' (D), effective uid, effective gid,
                saved uid, saved gid, filesystem uid, filesystem gid, elapsed
                time (hertz), is_process (y/n), OpenVZ  virtual pid (VPID),
                OpenVZ container id (CTID) and Docker container id (CID).

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

       PRE      For every process one line is shown.
                Subsequent fields: PID, name (between brackets), 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 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.

SIGNALS
       By sending the SIGUSR1 signal to 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 atop a final sample will be forced
       after which atop will terminate.

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
       /var/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.

       /etc/default/atop
            Configuration file to overrule the settings of atop that runs in
            the background to create the daily logfile.  This file is created
            when atop is installed.  The default settings are:

       LOGOPTS="-R"
               LOGINTERVAL=600
               LOGGENERATIONS=28

       /var/log/atop/atop_YYYYMMDD
            Raw file, where YYYYMMDD are digits representing the current date.
            This name is used by atop running in the background 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.

       /var/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), atopconvert(1), atoprc(5), atopacctd(8), netatop(4),
       netatopd(8), atopgpud(8), logrotate(8)
       https://www.atoptool.nl

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



Linux                            November 2019                         ATOP(1)