<para>Unit configuration files for services, slices, scopes,
sockets, mount points, and swap devices share a subset of
configuration options for resource control of spawned
- processes. Internally, this relies on the the Control Groups
+ processes. Internally, this relies on the Control Groups
kernel concept for organizing processes in a hierarchial tree of
named groups for the purpose of resource management.</para>
<para>See the <ulink
url="http://www.freedesktop.org/wiki/Software/systemd/ControlGroupInterface/">New
- Control Group Interfaces</ulink> for an introduction how to make
+ Control Group Interfaces</ulink> for an introduction on how to make
use of resource control APIs from programs.</para>
</refsect1>
<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>
<term><varname>CPUShares=<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
- attribute, which defaults to 1024. For details about this
- control group attribute, see <ulink
+ <para>Assign the specified CPU time share weight to the
+ processes executed. Takes an integer value. This controls
+ 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 a
+ slice relative to their CPU time share weight.</para>
+
+ <para>Implies <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 "%") or an
+ absolute time (suffixed by one of the common time units, us,
+ ms, s, ...). 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 alloting CPU
+ time on more than one CPU. If an absolute time is specified
+ the processes of this unit will get this much absolute time
+ within each quota period, at maximum. 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>CPUShares=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>
+
+ <varlistentry>
+ <term><varname>CPUQuotaPeriodSec=</varname></term>
+
+ <listitem>
+ <para>Specify the CPU quota period to use. Defaults to
+ 100ms. This controls the <literal>cpu.cfs_period_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>Implies <literal>CPUAccounting=true</literal>.</para>
</listitem>
</varlistentry>
+ <varlistentry>
+ <term><varname>StartupCPUShares=<replaceable>weight</replaceable></varname></term>
+
+ <listitem>
+ <para>Similar to <varname>CPUShares=</varname>. However,
+ only be assigned on startup state. After finishing startup, will be
+ re-assigned by <varname>CPUShares=</varname>. If
+ <varname>CPUShares=</varname> is not specified, then it will be
+ assigned to default(1024).</para>
+ </listitem>
+ </varlistentry>
+
<varlistentry>
<term><varname>MemoryAccounting=</varname></term>
<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>
</listitem>
</varlistentry>
+ <varlistentry>
+ <term><varname>StartupBlockIOWeight=<replaceable>weight</replaceable></varname></term>
+
+ <listitem>
+ <para>Similar to <varname>BlockIOWeight=</varname>. However,
+ only be assigned on startup state. After finishing startup, will be
+ re-assigned by <varname>BlockIOWeight=</varname>. If
+ <varname>BlockIOWeight=</varname> is not specified, then it will be
+ assigned to default(1000).</para>
+ </listitem>
+ </varlistentry>
+
<varlistentry>
<term><varname>BlockIODeviceWeight=<replaceable>device</replaceable> <replaceable>weight</replaceable></varname></term>
path and a weight value to specify the device specific
weight value, between 10 and 1000. (Example: "/dev/sda
500"). The file path may be specified as path to a block
- device node or as any other file in which case the backing
+ device node or as any other file, in which case the backing
block device of the file system of the file is
determined. This controls the
<literal>blkio.weight_device</literal> control group
case the backing block device of the file system of the file
is used. If the bandwidth is suffixed with K, M, G, or T,
the specified bandwidth is parsed as Kilobytes, Megabytes,
- Gigabytes, or Terabytes, respectively (Example:
+ Gigabytes, or Terabytes, respectively, to the base of
+ 1000. (Example:
"/dev/disk/by-path/pci-0000:00:1f.2-scsi-0:0:0:0 5M"). This
controls the <literal>blkio.read_bps_device</literal> and
<literal>blkio.write_bps_device</literal> control group
attributes. Use this option multiple times to set bandwidth
limits for multiple devices. For details about these control
- group attributes, see
- <ulink url="https://www.kernel.org/doc/Documentation/cgroups/blkio-controller.txt">blkio-controller.txt</ulink>.
+ group attributes, see <ulink
+ url="https://www.kernel.org/doc/Documentation/cgroups/blkio-controller.txt">blkio-controller.txt</ulink>.
</para>
<para>Implies
<listitem>
<para>Control access to specific device nodes by the
executed processes. Takes two space-separated strings: a
- device node path (such as <filename>/dev/null</filename>)
- followed by a combination of <constant>r</constant>,
- <constant>w</constant>, <constant>m</constant> to control
+ device node specifier followed by a combination of
+ <constant>r</constant>, <constant>w</constant>,
+ <constant>m</constant> to control
<emphasis>r</emphasis>eading, <emphasis>w</emphasis>riting,
- or creation of the specific device node by the unit
+ or creation of the specific device node(s) by the unit
(<emphasis>m</emphasis>knod), respectively. This controls
the <literal>devices.allow</literal> and
<literal>devices.deny</literal> control group
- attributes. For details about these control group attributes,
- see <ulink
+ attributes. For details about these control group
url="https://www.kernel.org/doc/Documentation/cgroups/devices.txt">devices.txt</ulink>.</para>
+
+ <para>The device node specifier is either a path to a device
+ node in the file system, starting with
+ <filename>/dev/</filename>, or a string starting with either
+ <literal>char-</literal> or <literal>block-</literal>
+ 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. 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. <literal>char-cpu/*</literal> is a specifier
+ matching all CPU related device groups.</para>
</listitem>
</varlistentry>
~ianmdlvl / elogind.git / blobdiff