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hashmap: return more information from resize_buckets()
[elogind.git] / man / systemd-cgtop.xml
1 <?xml version='1.0'?> <!--*-nxml-*-->
2 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
3         "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
4
5 <!--
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7
8   Copyright 2012 Lennart Poettering
9
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11   under the terms of the GNU Lesser General Public License as published by
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22 -->
23
24 <refentry id="systemd-cgtop"
25           xmlns:xi="http://www.w3.org/2001/XInclude">
26
27         <refentryinfo>
28                 <title>systemd-cgtop</title>
29                 <productname>systemd</productname>
30
31                 <authorgroup>
32                         <author>
33                                 <contrib>Developer</contrib>
34                                 <firstname>Lennart</firstname>
35                                 <surname>Poettering</surname>
36                                 <email>lennart@poettering.net</email>
37                         </author>
38                 </authorgroup>
39         </refentryinfo>
40
41         <refmeta>
42                 <refentrytitle>systemd-cgtop</refentrytitle>
43                 <manvolnum>1</manvolnum>
44         </refmeta>
45
46         <refnamediv>
47                 <refname>systemd-cgtop</refname>
48                 <refpurpose>Show top control groups by their resource usage</refpurpose>
49         </refnamediv>
50
51         <refsynopsisdiv>
52                 <cmdsynopsis>
53                         <command>systemd-cgtop</command>
54                         <arg choice="opt" rep="repeat">OPTIONS</arg>
55                 </cmdsynopsis>
56         </refsynopsisdiv>
57
58         <refsect1>
59                 <title>Description</title>
60
61                 <para><command>systemd-cgtop</command> shows the top
62                 control groups of the local Linux control group
63                 hierarchy, ordered by their CPU, memory, or disk I/O load. The
64                 display is refreshed in regular intervals (by default
65                 every 1s), similar in style to
66                 <citerefentry project='man-pages'><refentrytitle>top</refentrytitle><manvolnum>1</manvolnum></citerefentry>.
67                 If <command>systemd-cgtop</command> is not connected
68                 to a tty, only one iteration is performed and no
69                 columns headers are printed. This mode is suitable for
70                 scripting.</para>
71
72                 <para>Resource usage is only accounted for control
73                 groups in the relevant hierarchy, i.e. CPU usage is
74                 only accounted for control groups in the
75                 <literal>cpuacct</literal> hierarchy, memory usage
76                 only for those in <literal>memory</literal> and disk
77                 I/O usage for those in <literal>blkio</literal>. If
78                 resource monitoring for these resources is required,
79                 it is recommended to add the
80                 <varname>CPUAccounting=1</varname>,
81                 <varname>MemoryAccounting=1</varname> and
82                 <varname>BlockIOAccounting=1</varname> settings in the
83                 unit files in question. See
84                 <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry>
85                 for details.</para>
86
87                 <para>To emphasize this: unless
88                 <literal>CPUAccounting=1</literal>,
89                 <literal>MemoryAccounting=1</literal> and
90                 <literal>BlockIOAccounting=1</literal> are enabled for
91                 the services in question, no resource accounting will
92                 be available for system services and the data shown by
93                 <command>systemd-cgtop</command> will be
94                 incomplete.</para>
95         </refsect1>
96
97         <refsect1>
98                 <title>Options</title>
99
100                 <para>The following options are understood:</para>
101
102                 <variablelist>
103                         <varlistentry>
104                                 <term><option>-p</option></term>
105
106                                 <listitem><para>Order by control group
107                                 path name.</para></listitem>
108                         </varlistentry>
109
110                         <varlistentry>
111                                 <term><option>-t</option></term>
112
113                                 <listitem><para>Order by number of
114                                 tasks in control
115                                 group (i.e. threads and processes).</para></listitem>
116                         </varlistentry>
117
118                         <varlistentry>
119                                 <term><option>-c</option></term>
120
121                                 <listitem><para>Order by CPU load.</para></listitem>
122                         </varlistentry>
123
124                         <varlistentry>
125                                 <term><option>-m</option></term>
126
127                                 <listitem><para>Order by memory usage.</para></listitem>
128                         </varlistentry>
129
130                         <varlistentry>
131                                 <term><option>-i</option></term>
132
133                                 <listitem><para>Order by disk I/O load.</para></listitem>
134                         </varlistentry>
135
136                         <varlistentry>
137                                 <term><option>-b</option></term>
138                                 <term><option>--batch</option></term>
139
140                                 <listitem><para>Run in "batch" mode:
141                                 do not accept input and run until the
142                                 iteration limit set with
143                                 <option>--iterations</option> is
144                                 exhausted or until killed. This mode
145                                 could be useful for sending output
146                                 from <command>systemd-cgtop</command>
147                                 to other programs or to a
148                                 file.</para></listitem>
149                         </varlistentry>
150
151                         <varlistentry>
152                                 <term><option>-n</option></term>
153                                 <term><option>--iterations=</option></term>
154
155                                 <listitem><para>Perform only this many
156                                 iterations.</para></listitem>
157                         </varlistentry>
158
159                         <varlistentry>
160                                 <term><option>-d</option></term>
161                                 <term><option>--delay=</option></term>
162
163                                 <listitem><para>Specify refresh delay
164                                 in seconds (or if one of
165                                 <literal>ms</literal>,
166                                 <literal>us</literal>,
167                                 <literal>min</literal> is specified as
168                                 unit in this time
169                                 unit).</para></listitem>
170                         </varlistentry>
171
172                         <varlistentry>
173                                 <term><option>--depth=</option></term>
174
175                                 <listitem><para>Maximum control group
176                                 tree traversal depth. Specifies how
177                                 deep <command>systemd-cgtop</command>
178                                 shall traverse the control group
179                                 hierarchies. If 0 is specified, only
180                                 the root group is monitored. For 1,
181                                 only the first level of control groups
182                                 is monitored, and so on. Defaults to
183                                 3.</para></listitem>
184                         </varlistentry>
185
186                         <xi:include href="standard-options.xml" xpointer="help" />
187                         <xi:include href="standard-options.xml" xpointer="version" />
188                 </variablelist>
189
190         </refsect1>
191
192
193         <refsect1>
194                 <title>Keys</title>
195
196                 <para><command>systemd-cgtop</command> is an
197                 interactive tool and may be controlled via user input
198                 using the following keys:</para>
199
200                 <variablelist>
201                         <varlistentry>
202                                 <term>h</term>
203
204                                 <listitem><para>Shows a short help text.</para></listitem>
205                         </varlistentry>
206
207                         <varlistentry>
208                                 <term>SPACE</term>
209
210                                 <listitem><para>Immediately refresh output.</para></listitem>
211                         </varlistentry>
212
213                         <varlistentry>
214                                 <term>q</term>
215
216                                 <listitem><para>Terminate the program.</para></listitem>
217                         </varlistentry>
218
219
220                         <varlistentry>
221                                 <term>p</term>
222                                 <term>t</term>
223                                 <term>c</term>
224                                 <term>m</term>
225                                 <term>i</term>
226
227                                 <listitem><para>Sort the control groups
228                                 by path, number of tasks, CPU load,
229                                 memory usage, or IO
230                                 load, respectively.</para></listitem>
231                         </varlistentry>
232
233                         <varlistentry>
234                                 <term>%</term>
235
236                                 <listitem><para>Toggle between showing CPU time as
237                                 time or percentage.</para></listitem>
238                         </varlistentry>
239
240                         <varlistentry>
241                                 <term>+</term>
242                                 <term>-</term>
243
244                                 <listitem><para>Increase
245                                 or decrease refresh
246                                 delay, respectively.</para></listitem>
247                         </varlistentry>
248
249                 </variablelist>
250         </refsect1>
251
252         <refsect1>
253                 <title>Exit status</title>
254
255                 <para>On success, 0 is returned, a non-zero failure
256                 code otherwise.</para>
257         </refsect1>
258
259         <refsect1>
260                 <title>See Also</title>
261                 <para>
262                         <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
263                         <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
264                         <citerefentry><refentrytitle>systemd-cgls</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
265                         <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
266                         <citerefentry project='man-pages'><refentrytitle>top</refentrytitle><manvolnum>1</manvolnum></citerefentry>
267                 </para>
268         </refsect1>
269
270 </refentry>