systemd-cgtop - Man Page

Show top control groups by their resource usage

Examples (TL;DR)

Start an interactive view: systemd-cgtop
Change the sort order: systemd-cgtop --order cpu|memory|path|tasks|io
Show the CPU usage by time instead of percentage: systemd-cgtop --cpu=percentage
Change the update interval in seconds (or one of these time units: ms, us, min): systemd-cgtop [-d|--delay] interval
Only count userspace processes (without kernel threads): systemd-cgtop -P

systemd-cgtop shows the top control groups of the local Linux control group hierarchy, ordered by their CPU, memory, or disk I/O load. The display is refreshed in regular intervals (by default every 1s), similar in style to top(1). If a control group path is specified, shows only the services of the specified control group.

If systemd-cgtop is not connected to a tty, no column headers are printed and the default is to only run one iteration. The --iterations= argument, if given, is honored. This mode is suitable for scripting.

Resource usage is only accounted for control groups with the appropriate controllers turned on: "memory" controller for memory usage and "io" controller for disk I/O consumption. If resource monitoring for these resources is required, it is recommended to add the MemoryAccounting=1 and IOAccounting=1 settings in the unit files in question. See systemd.resource-control(5) for details.

The CPU load value can be between 0 and 100 times the number of processors the system has. For example, if the system has 8 processors, the CPU load value is going to be between 0% and 800%. The number of processors can be found in "/proc/cpuinfo".

To emphasize: unless "MemoryAccounting=1" and "IOAccounting=1" are enabled for the services in question, no resource accounting will be available for system services and the data shown by systemd-cgtop will be incomplete.

Options

The following options are understood:

-p, --order=path

Order by control group path name.

-t, --order=tasks

Order by number of tasks/processes in the control group.

-c, --order=cpu

Order by CPU load.

-m, --order=memory

Order by memory usage.

-i, --order=io

Order by disk I/O load.

-b, --batch

Run in "batch" mode: do not accept input and run until the iteration limit set with --iterations= is exhausted or until killed. This mode could be useful for sending output from systemd-cgtop to other programs or to a file.

Added in version 188.

-r, --raw

Format byte counts (as in memory usage and I/O metrics) and CPU time with raw numeric values rather than human-readable numbers.

Added in version 221.

--cpu=percentage, --cpu=time

Controls whether the CPU usage is shown as percentage or time. By default, the CPU usage is shown as percentage. When the option is used without an argument, it is equivalent to --cpu=time. This setting may also be toggled at runtime by pressing the % key.

Added in version 226.

-P

Count only userspace processes instead of all tasks. By default, all tasks are counted: each kernel thread and each userspace thread individually. With this setting, kernel threads are excluded from the count and each userspace process only counts as one task, regardless of how many threads it consists of. This setting may also be toggled at runtime by pressing the P key. This option may not be combined with -k.

Added in version 227.

-k

Count only userspace processes and kernel threads instead of all tasks. By default, all tasks are counted: each kernel thread and each userspace thread individually. With this setting, kernel threads are included in the count and each userspace process only counts as one task, regardless of how many threads it consists of. This setting may also be toggled at runtime by pressing the k key. This option may not be combined with -P.

Added in version 226.

--recursive=

Controls whether the number of processes shown for a control group shall include all processes that are contained in any of the child control groups as well. Takes a boolean argument, which defaults to "yes". If enabled, the processes in child control groups are included, if disabled, only the processes in the control group itself are counted. This setting may also be toggled at runtime by pressing the r key. Note that this setting only applies to process counting, i.e. when the -P or -k options are used. When all tasks are counted, setting this option to "no" is rejected with an error, as task counting is always recursive.

Added in version 226.

-n, --iterations=

Perform only this many iterations. A value of 0 indicates that the program should run indefinitely.

Added in version 188.

-1

A shortcut for --iterations=1.

Added in version 238.

-d, --delay=

Specify refresh delay in seconds (or if one of "ms", "us", "min" is specified as unit in this time unit). This setting may also be increased and decreased at runtime by pressing the + and - keys.

--depth=

Maximum control group tree traversal depth. Specifies how deep systemd-cgtop shall traverse the control group hierarchies. If 0 is specified, only the root group is monitored. For 1, only the first level of control groups is monitored, and so on. Defaults to 3.

-M MACHINE, --machine=MACHINE

Limit control groups shown to the part corresponding to the container MACHINE. This option may not be used when a control group path is specified.

Added in version 227.

-h, --help

Print a short help text and exit.

--version

Print a short version string and exit.

Keys

systemd-cgtop is an interactive tool and may be controlled via user input using the following keys:

h

Shows a short help text.

Space

Immediately refresh output.

Added in version 226.

q

Terminate the program.

p, t, c, m, i

Sort the control groups by path, number of tasks, CPU load, memory usage, or I/O load, respectively. This setting may also be controlled using the --order= command line switch.

%

Toggle between showing CPU time as time or percentage. This setting may also be controlled using the --cpu= command line switch.

Added in version 201.

+, -

Increase or decrease refresh delay, respectively. This setting may also be controlled using the --delay= command line switch.

P

Toggle between counting all tasks, or only userspace processes. This setting may also be controlled using the -P command line switch (see above).

Added in version 227.

k

Toggle between counting all tasks, or only userspace processes and kernel threads. This setting may also be controlled using the -k command line switch (see above).

Added in version 226.

r

Toggle between recursively including or excluding processes in child control groups in control group process counts. This setting may also be controlled using the --recursive= command line switch. This key is not available if all tasks are counted, it is only available if processes are counted, as enabled with the P or k keys.

Added in version 226.