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systemd/man/systemd-cgtop.xml
Lennart Poettering 45d7a8bb6c cgtop: major modernizations
In preparation of the unified cgroup support, let's clean up cgtop:

a) rework time code to be based on "nsec_t" rather than "struct timespec"

b) Introduce long option --order= for selecting ordering

c) count number of processes only in the main hierarchy, don't bother
   with the controller hierarchies. We don't allow orthogonal
   hierarchies in systemd anymore, hence there's no point to check the
   other hierarchies.

d) Deal with non-monotonic cpuacct values (see #749)

e) When sorting groups, don't do prefix compare when ordering by number
   of tasks, since this is not accumulative for all children.

f) Actually make --cpu without parameter work

g) Don't output control characters when we get them as input.

Fixes #749.
2015-08-28 02:27:29 +02:00

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XML

<?xml version='1.0'?> <!--*- Mode: nxml; nxml-child-indent: 2; indent-tabs-mode: nil -*-->
<!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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<refentry id="systemd-cgtop"
xmlns:xi="http://www.w3.org/2001/XInclude">
<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 project='man-pages'><refentrytitle>top</refentrytitle><manvolnum>1</manvolnum></citerefentry>.</para>
<para>If <command>systemd-cgtop</command> is not connected to a
tty, no column headers are printed and the default is to only run
one iteration. The <varname>--iterations=</varname> argument, if
given, is honored. 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>. If resource monitoring for
these resources is required, it is recommended to add the
<varname>CPUAccounting=1</varname>,
<varname>MemoryAccounting=1</varname> and
<varname>BlockIOAccounting=1</varname> settings in the unit files
in question. See
<citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry>
for details.</para>
<para>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 <literal>/proc/cpuinfo</literal>.</para>
<para>To emphasize this: unless
<literal>CPUAccounting=1</literal>,
<literal>MemoryAccounting=1</literal> and
<literal>BlockIOAccounting=1</literal> are enabled for the
services in question, 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>-p</option></term>
<term><option>--order=path</option></term>
<listitem><para>Order by control group
path name.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>-t</option></term>
<term><option>--order=tasks</option></term>
<listitem><para>Order by number of processes in control group.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>-c</option></term>
<term><option>--order=cpu</option></term>
<listitem><para>Order by CPU load.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>-m</option></term>
<term><option>--order=memory</option></term>
<listitem><para>Order by memory usage.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>-i</option></term>
<term><option>--order=io</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>-r</option></term>
<term><option>--raw</option></term>
<listitem><para>Format byte counts (as in memory usage and IO metrics)
with raw numeric values rather than human-readable
numbers.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>--cpu=percentage</option></term>
<term><option>--cpu=time</option></term>
<listitem><para>Controls whether the CPU usage is shown as
percentage or time. By default the CPU usage is shown as
percentage.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>-n</option></term>
<term><option>--iterations=</option></term>
<listitem><para>Perform only this many iterations. A value of 0
indicates that the program should run indefinitely.</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>
<xi:include href="standard-options.xml" xpointer="help" />
<xi:include href="standard-options.xml" xpointer="version" />
</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>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
<citerefentry project='man-pages'><refentrytitle>top</refentrytitle><manvolnum>1</manvolnum></citerefentry>
</para>
</refsect1>
</refentry>