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<refentry id="systemd-cgtop">
<refentryinfo>
<title>systemd-cgtop</title>
<productname>systemd</productname>
<authorgroup>
<author>
<contrib>Developer</contrib>
<firstname>Lennart</firstname>
<surname>Poettering</surname>
<email>lennart@poettering.net</email>
</author>
</authorgroup>
</refentryinfo>
<refmeta>
<refentrytitle>systemd-cgtop</refentrytitle>
<manvolnum>1</manvolnum>
</refmeta>
<refnamediv>
<refname>systemd-cgtop</refname>
<refpurpose>Show top control groups by their resource usage</refpurpose>
</refnamediv>
<refsynopsisdiv>
<cmdsynopsis>
<command>systemd-cgtop</command>
<arg choice="opt" rep="repeat">OPTIONS</arg>
</cmdsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Description</title>
<para><command>systemd-cgtop</command> 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
<citerefentry><refentrytitle>top</refentrytitle><manvolnum>1</manvolnum></citerefentry>.
If <command>systemd-cgtop</command> is not connected
to a tty, only one iteration is performed and no
columns headers are printed. This mode is suitable for
scripting.</para>
<para>Resource usage is only accounted for control
groups in the relevant hierarchy, i.e. CPU usage is
only accounted for control groups in the
<literal>cpuacct</literal> hierarchy, memory usage
only for those in <literal>memory</literal> and disk
I/O usage for those in
<literal>blkio</literal>. <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>
by default places all services in their own control
group in the <literal>cpuacct</literal> hierarchy, but
not in <literal>memory</literal> nor
<literal>blkio</literal>. If resource monitoring for
these resources is required, it is recommended to add
<literal>blkio</literal> and <literal>memory</literal>
to the <varname>DefaultControllers=</varname> setting
in <filename>/etc/systemd/system.conf</filename> (see
<citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>
for details). Alternatively, it is possible to enable
resource accounting individually for services, by
making use of the <varname>ControlGroup=</varname>
option in the unit files (See
<citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
for details).</para>
<para>To emphasize this: unless
<literal>blkio</literal> and <literal>memory</literal>
are enabled for the services in question with either
of the options suggested above no resource accounting
will be available for system services and the data shown
by <command>systemd-cgtop</command> will be
incomplete.</para>
</refsect1>
<refsect1>
<title>Options</title>
<para>The following options are understood:</para>
<variablelist>
<varlistentry>
<term><option>-h</option></term>
<term><option>--help</option></term>
<listitem><para>Prints a short help
text and exits.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>--version</option></term>
<listitem><para>Prints a version string and
exits.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>-p</option></term>
<listitem><para>Order by control group
path name.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>-t</option></term>
<listitem><para>Order by number of
tasks in control
group (i.e. threads and processes).</para></listitem>
</varlistentry>
<varlistentry>
<term><option>-c</option></term>
<listitem><para>Order by CPU load.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>-m</option></term>
<listitem><para>Order by memory usage.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>-i</option></term>
<listitem><para>Order by disk I/O load.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>-b</option></term>
<term><option>--batch</option></term>
<listitem><para>Run in "batch" mode:
do not accept input and run until the
iteration limit set with
<option>--iterations</option> is
exhausted or until killed. This mode
could be useful for sending output
from <command>systemd-cgtop</command>
to other programs or to a
file.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>-n</option></term>
<term><option>--iterations=</option></term>
<listitem><para>Perform only this many
iterations.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>-d</option></term>
<term><option>--delay=</option></term>
<listitem><para>Specify refresh delay
in seconds (or if one of
<literal>ms</literal>,
<literal>us</literal>,
<literal>min</literal> is specified as
unit in this time
unit).</para></listitem>
</varlistentry>
<varlistentry>
<term><option>--depth=</option></term>
<listitem><para>Maximum control group
tree traversal depth. Specifies how
deep <command>systemd-cgtop</command>
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.</para></listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Keys</title>
<para><command>systemd-cgtop</command> is an
interactive tool and may be controlled via user input
using the following keys:</para>
<variablelist>
<varlistentry>
<term>h</term>
<listitem><para>Shows a short help text.</para></listitem>
</varlistentry>
<varlistentry>
<term>SPACE</term>
<listitem><para>Immediately refresh output.</para></listitem>
</varlistentry>
<varlistentry>
<term>q</term>
<listitem><para>Terminate the program.</para></listitem>
</varlistentry>
<varlistentry>
<term>p</term>
<term>t</term>
<term>c</term>
<term>m</term>
<term>i</term>
<listitem><para>Sort the control groups
by path, number of tasks, CPU load,
memory usage, or IO
load, respectively.</para></listitem>
</varlistentry>
<varlistentry>
<term>%</term>
<listitem><para>Toggle between showing CPU time as
time or percentage.</para></listitem>
</varlistentry>
<varlistentry>
<term>+</term>
<term>-</term>
<listitem><para>Increase
or decrease refresh
delay, respectively.</para></listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Exit status</title>
<para>On success 0 is returned, a non-zero failure
code otherwise.</para>
</refsect1>
<refsect1>
<title>See Also</title>
<para>
<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemd-cgls</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
<citerefentry><refentrytitle>top</refentrytitle><manvolnum>1</manvolnum></citerefentry>
</para>
</refsect1>
</refentry>