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<!--
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-Copyright 2013 Zbigniew Jędrzejewski-Szmek
+ Copyright 2013 Zbigniew Jędrzejewski-Szmek
-systemd is free software; you can redistribute it and/or modify it
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+ You should have received a copy of the GNU Lesser General Public License
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-->
<refentry id="systemd.resource-control">
sockets, mount points, and swap devices share a subset of
configuration options for resource control of spawned
processes. Internally, this relies on the Control Groups
- kernel concept for organizing processes in a hierarchial tree of
+ kernel concept for organizing processes in a hierarchical tree of
named groups for the purpose of resource management.</para>
<para>This man page lists the configuration options shared by
<para>Turn on CPU usage accounting for this unit. Takes a
boolean argument. Note that turning on CPU accounting for
one unit might also implicitly turn it on for all units
- contained in the same slice and for all its parent slices and
- the units contained therein.</para>
+ contained in the same slice and for all its parent slices
+ and the units contained therein. The system default for this
+ setting maybe controlled with
+ <varname>DefaultCPUAccounting=</varname> in
+ <citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><varname>CPUShares=<replaceable>weight</replaceable></varname></term>
+ <term><varname>StartupCPUShares=<replaceable>weight</replaceable></varname></term>
<listitem>
- <para>Assign the specified overall CPU time share weight to
- the processes executed. Takes an integer value. This
- controls the <literal>cpu.shares</literal> control group
+ <para>Assign the specified CPU time share weight to the
+ processes executed. Those options take an integer value and
+ control the <literal>cpu.shares</literal> control group
attribute, which defaults to 1024. For details about this
control group attribute, see <ulink
+ url="https://www.kernel.org/doc/Documentation/scheduler/sched-design-CFS.txt">sched-design-CFS.txt</ulink>.
+ The available CPU time is split up among all units within
+ one slice relative to their CPU time share weight.</para>
+
+ <para>While <varname>StartupCPUShares=</varname> only
+ applies to the startup phase of the system,
+ <varname>CPUShares=</varname> applies to normal runtime of
+ the system, and if the former is not set also to the startup
+ phase. Using <varname>StartupCPUShares=</varname> allows
+ prioritizing specific services at boot-up differently than
+ during normal runtime.</para>
+
+ <para>Those options imply
+ <literal>CPUAccounting=true</literal>.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>CPUQuota=</varname></term>
+
+ <listitem>
+ <para>Assign the specified CPU time quota to the processes
+ executed. Takes a percentage value, suffixed with "%". The
+ percentage specifies how much CPU time the unit shall get at
+ maximum, relative to the total CPU time available on one
+ CPU. Use values > 100% for allotting CPU time on more than
+ one CPU. This controls the
+ <literal>cpu.cfs_quota_us</literal> control group
+ attribute. For details about this control group attribute,
+ see <ulink
url="https://www.kernel.org/doc/Documentation/scheduler/sched-design-CFS.txt">sched-design-CFS.txt</ulink>.</para>
+ <para>Example: <varname>CPUQuota=20%</varname> ensures that
+ the executed processes will never get more than 20% CPU time
+ on one CPU.</para>
+
<para>Implies <literal>CPUAccounting=true</literal>.</para>
</listitem>
</varlistentry>
<para>Turn on process and kernel memory accounting for this
unit. Takes a boolean argument. Note that turning on memory
accounting for one unit might also implicitly turn it on for
- all units contained in the same slice and for all its parent
- slices and the units contained therein.</para>
+ all its parent slices. The system default for this setting
+ maybe controlled with
+ <varname>DefaultMemoryAccounting=</varname> in
+ <citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
</listitem>
</varlistentry>
<para>Turn on Block IO accounting for this unit. Takes a
boolean argument. Note that turning on block IO accounting
for one unit might also implicitly turn it on for all units
- contained in the same slice and all for its parent slices and
- the units contained therein.</para>
+ contained in the same slice and all for its parent slices
+ and the units contained therein. The system default for this
+ setting maybe controlled with
+ <varname>DefaultBlockIOAccounting=</varname> in
+ <citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><varname>BlockIOWeight=<replaceable>weight</replaceable></varname></term>
-
- <listitem><para>Set the default
- overall block IO weight for the
- executed processes. Takes a single
- weight value (between 10 and 1000) to
- set the default block IO weight. This
- controls the
- <literal>blkio.weight</literal>
- control group attribute, which
- defaults to 1000. For details about
- this control group attribute, see
- <ulink
- url="https://www.kernel.org/doc/Documentation/cgroups/blkio-controller.txt">blkio-controller.txt</ulink>.</para>
+ <term><varname>StartupBlockIOWeight=<replaceable>weight</replaceable></varname></term>
+
+ <listitem><para>Set the default overall block IO weight for
+ the executed processes. Takes a single weight value (between
+ 10 and 1000) to set the default block IO weight. This controls
+ the <literal>blkio.weight</literal> control group attribute,
+ which defaults to 1000. For details about this control group
+ attribute, see <ulink
+ url="https://www.kernel.org/doc/Documentation/cgroups/blkio-controller.txt">blkio-controller.txt</ulink>.
+ The available IO bandwidth is split up among all units within
+ one slice relative to their block IO weight.</para>
+
+ <para>While <varname>StartupBlockIOWeight=</varname> only
+ applies to the startup phase of the system,
+ <varname>BlockIOWeight=</varname> applies to the later runtime
+ of the system, and if the former is not set also to the
+ startup phase. This allows prioritizing specific services at
+ boot-up differently than during runtime.</para>
<para>Implies
<literal>BlockIOAccounting=true</literal>.</para>
followed by a device group name, as listed in
<filename>/proc/devices</filename>. The latter is useful to
whitelist all current and future devices belonging to a
- specific device group at once. Examples:
- <filename>/dev/sda5</filename> is a path to a device node,
- referring to an ATA or SCSI block
+ specific device group at once. The device group is matched
+ according to file name globbing rules, you may hence use the
+ <literal>*</literal> and <literal>?</literal>
+ wildcards. Examples: <filename>/dev/sda5</filename> is a
+ path to a device node, referring to an ATA or SCSI block
device. <literal>char-pts</literal> and
<literal>char-alsa</literal> are specifiers for all pseudo
- TTYs and all ALSA sound devices, respectively.</para>
+ TTYs and all ALSA sound devices,
+ respectively. <literal>char-cpu/*</literal> is a specifier
+ matching all CPU related device groups.</para>
</listitem>
</varlistentry>
</listitem>
</varlistentry>
+ <varlistentry>
+ <term><varname>Delegate=</varname></term>
+
+ <listitem>
+ <para>Turns on delegation of further resource control
+ partitioning to processes of the unit. For unprivileged
+ services (i.e. those using the <varname>User=</varname>
+ setting) this allows processes to create a subhierarchy
+ beneath its control group path. For privileged services and
+ scopes this ensures the processes will have all control
+ group controllers enabled.</para>
+ </listitem>
+ </varlistentry>
+
</variablelist>
</refsect1>
~ianmdlvl / elogind.git / blobdiff