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systemd/man/systemd-cgtop.xml
Lennart Poettering 5430f7f2bc relicense to LGPLv2.1 (with exceptions)
We finally got the OK from all contributors with non-trivial commits to
relicense systemd from GPL2+ to LGPL2.1+.

Some udev bits continue to be GPL2+ for now, but we are looking into
relicensing them too, to allow free copy/paste of all code within
systemd.

The bits that used to be MIT continue to be MIT.

The big benefit of the relicensing is that closed source code may now
link against libsystemd-login.so and friends.
2012-04-12 00:24:39 +02:00

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<?xml version='1.0'?> <!--*-nxml-*-->
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
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Copyright 2012 Lennart Poettering
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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 <arg choice="opt" rep="repeat">OPTIONS</arg></command>
</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 and 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>.</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.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>-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>-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
2.</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>Change ordering of control groups
by path, number of tasks, CPU load,
memory usage resp. IO
load.</para></listitem>
</varlistentry>
<varlistentry>
<term>+</term>
<term>-</term>
<listitem><para>Increase,
resp. decrease refresh
delay.</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>