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|
<!DOCTYPE node PUBLIC
"-//freedesktop//DTD D-BUS Object Introspection 1.0//EN"
"http://www.freedesktop.org/standards/dbus/1.0/introspect.dtd" [
<!ENTITY ERROR_GENERAL "org.freedesktop.DeviceKit.Power.GeneralError">
]>
<node name="/" xmlns:doc="http://www.freedesktop.org/dbus/1.0/doc.dtd">
<interface name="org.freedesktop.DeviceKit.Power.QoS">
<doc:doc>
<doc:description>
<doc:para>
org.freedesktop.DeviceKit.Power.QoS is a DBus interface implimented
by DeviceKit-power.
It allows applications to request latencies, for example a couple of seconds
for an IM application, or a few hundred microseconds for a multiplayer game.
</doc:para>
<doc:para>
Use cases:
</doc:para>
<doc:itemizedlist>
<doc:listitem>
<doc:para>
I want my IM application to request 0.5s latency for messages.
</doc:para>
<doc:para>
I'm running an OpenGL simulation and want maximum performance,
even when on battery power.
</doc:para>
<doc:para>
I'm running an SQL server for a credit card company, and want the
server to request low latency CPU and network as any delay costs money.
</doc:para>
<doc:para>
I'm an admin, and want to change the power consumption vs. latency
from cron scripts so it uses high latency during the night for
maximum power saving, and low latency during business hours.
</doc:para>
<doc:para>
I want high throughput when copying files, but want low throughput
for downloading updates in the background.
</doc:para>
<doc:para>
I want my power manager to set all latencies to lowest when on
AC power.
</doc:para>
<doc:para>
I don't want my users messing with latency settings.
</doc:para>
<doc:para>
I'm and admin and I want to be able to override all latency
settings on my machines.
</doc:para>
</doc:listitem>
</doc:itemizedlist>
<doc:para>
Why don't applications use the PMQoS interface directly?
By providing a framework we can override requests by policy, and also
control requests from random services.
You also can't set latencies unless you're the root user, which is not
suitable for the desktop use case.
</doc:para>
<doc:para>
Of course, you can do if you really want, but then you loose the
benefits of the query interface and the policy override,
and have to run your application as root.
</doc:para>
</doc:description>
</doc:doc>
<!-- ************************************************************ -->
<method name="SetMinimumLatency">
<annotation name="org.freedesktop.DBus.GLib.Async" value=""/>
<arg name="type" direction="in" type="s">
<doc:doc>
<doc:summary>
The type of latency to control, <doc:tt>cpu_dma</doc:tt> or
<doc:tt>network</doc:tt>.
</doc:summary>
</doc:doc>
</arg>
<arg name="value" direction="in" type="i">
<doc:doc>
<doc:summary>
The value, in microseconds or kilobits per second.
The value <doc:tt>-1</doc:tt> means unset and the default is used.
</doc:summary>
</doc:doc>
</arg>
<doc:doc>
<doc:description>
<doc:para>
Set the minimum acceptable latency of the system.
Setting this value tells the system to not attempt latencies below this setting.
This may be useful in a data center or server room, when you want to override the
latency requests from applications.
This may be required if the server room is operating outside a standard thermal
or power envelope, and an override is required.
You do not have to use this method during normal operation.
</doc:para>
</doc:description>
<doc:permission>Callers need the <doc:tt>org.freedesktop.devicekit.power.latency.set-minimum-latency</doc:tt> authorization</doc:permission>
<doc:errors>
<doc:error name="&ERROR_GENERAL;">if an error occured while setting the latency</doc:error>
</doc:errors>
</doc:doc>
</method>
<!-- ************************************************************ -->
<method name="RequestLatency">
<annotation name="org.freedesktop.DBus.GLib.Async" value=""/>
<arg name="type" direction="in" type="s">
<doc:doc>
<doc:summary>
The type of latency to control, <doc:tt>cpu_dma</doc:tt> or
<doc:tt>network</doc:tt>.
</doc:summary>
</doc:doc>
</arg>
<arg name="value" direction="in" type="i">
<doc:doc>
<doc:summary>
The value, in microseconds or kilobits per second.
The value <doc:tt>-1</doc:tt> means remove all latency requirements.
</doc:summary>
</doc:doc>
</arg>
<arg name="persistent" direction="in" type="b">
<doc:doc>
<doc:summary>
If the latency request outlives the connection.
When the application issuing the request disconnects from the system
bus, the latency request is automatically cleaned up.
By setting this flag to TRUE, the request is not cleaned up when
the client disconnects, and the cookie is preserved acress reboots.
</doc:summary>
</doc:doc>
</arg>
<arg name="cookie" direction="out" type="u">
<doc:doc>
<doc:summary>
A cookie that identifies the request. This allows an application or
service to request multiple latency settings from one process, and for
other processes to cancel requests.
</doc:summary>
</doc:doc>
</arg>
<doc:doc>
<doc:description>
<doc:para>
Set the required latency of an application or service.
</doc:para>
</doc:description>
<doc:permission>
Callers need the
<doc:tt>org.freedesktop.devicekit.power.latency.request-latency-persistent</doc:tt>
authorization if <doc:tt>persistent</doc:tt> is TRUE, or
<doc:tt>org.freedesktop.devicekit.power.latency.request-latency</doc:tt> otherwise.
</doc:permission>
<doc:errors>
<doc:error name="&ERROR_GENERAL;">if an error occured while setting the latency</doc:error>
</doc:errors>
</doc:doc>
</method>
<!-- ************************************************************ -->
<method name="CancelRequest">
<annotation name="org.freedesktop.DBus.GLib.Async" value=""/>
<arg name="type" direction="in" type="s">
<doc:doc>
<doc:summary>
The type of latency to control, <doc:tt>cpu_dma</doc:tt> or
<doc:tt>network</doc:tt>.
</doc:summary>
</doc:doc>
</arg>
<arg name="cookie" direction="in" type="u">
<doc:doc>
<doc:summary>
A cookie that identifies the request. This allows an application or
serivice to request multiple latency settings from one process.
</doc:summary>
</doc:doc>
</arg>
<doc:doc>
<doc:description>
<doc:para>
Cancel the latency request from the application or service.
</doc:para>
</doc:description>
<doc:permission>
Callers need the
<doc:tt>org.freedesktop.devicekit.power.latency.cancel-request</doc:tt>
authorization if they were not the one issuing the request.
</doc:permission>
<doc:errors>
<doc:error name="&ERROR_GENERAL;">if an error occured while clearing the latency</doc:error>
</doc:errors>
</doc:doc>
</method>
<!-- ************************************************************ -->
<method name="GetLatency">
<arg name="type" direction="in" type="s">
<doc:doc>
<doc:summary>
The type of latency to return, <doc:tt>cpu_dma</doc:tt> or
<doc:tt>network</doc:tt>.
</doc:summary>
</doc:doc>
</arg>
<arg name="value" direction="out" type="i">
<doc:doc>
<doc:summary>
The value, in microseconds or kilobits per second.
The value <doc:tt>-1</doc:tt> means not set or unavailable.
</doc:summary>
</doc:doc>
</arg>
<doc:doc>
<doc:description>
<doc:para>
Get the lowest latency state on the system at the current time.
</doc:para>
</doc:description>
<doc:errors>
<doc:error name="&ERROR_GENERAL;">if an error occured while getting the latency</doc:error>
</doc:errors>
</doc:doc>
</method>
<!-- ************************************************************ -->
<signal name="LatencyChanged">
<arg name="type" direction="out" type="s">
<doc:doc>
<doc:summary>
The type of latency that changed, <doc:tt>cpu_dma</doc:tt> or
<doc:tt>network</doc:tt>.
</doc:summary>
</doc:doc>
</arg>
<arg name="value" direction="out" type="i">
<doc:doc>
<doc:summary>
The value, in microseconds or kilobits per second.
The value <doc:tt>-1</doc:tt> means not set or unavailable.
</doc:summary>
</doc:doc>
</arg>
<doc:doc>
<doc:description>
<doc:para>
Some latency value has changed.
</doc:para>
</doc:description>
</doc:doc>
</signal>
<!-- ************************************************************ -->
<method name="GetLatencyRequests">
<arg name="requests" direction="out" type="a(uuusxbssi)">
<doc:doc>
<doc:summary>
The request lists, where each application can request different
latency types.
<doc:list>
<doc:item>
<doc:term>cookie</doc:term>
<doc:definition>
The random cookie that identifies the request.
</doc:definition>
</doc:item>
<doc:item>
<doc:term>uid</doc:term>
<doc:definition>
The user ID that issued the request.
</doc:definition>
</doc:item>
<doc:item>
<doc:term>pid</doc:term>
<doc:definition>
The process ID of the application.
</doc:definition>
</doc:item>
<doc:item>
<doc:term>exec</doc:term>
<doc:definition>
The executable that issued the request.
</doc:definition>
</doc:item>
<doc:item>
<doc:term>timespec</doc:term>
<doc:definition>
The number of seconds since the epoch.
</doc:definition>
</doc:item>
<doc:item>
<doc:term>persistent</doc:term>
<doc:definition>
If the request is persistent and outlives the connection lifetime.
</doc:definition>
</doc:item>
<doc:item>
<doc:term>type</doc:term>
<doc:definition>
The type of the request, <doc:tt>cpu_dma</doc:tt> or
<doc:tt>network</doc:tt>.
</doc:definition>
</doc:item>
<doc:item>
<doc:term>value</doc:term>
<doc:definition>
The value, in microseconds or kilobits per second.
</doc:definition>
</doc:item>
</doc:list>
</doc:summary></doc:doc>
</arg>
<doc:doc>
<doc:description>
<doc:para>
Gets all the system requests from all services and applications.
</doc:para>
</doc:description>
</doc:doc>
</method>
<!-- ************************************************************ -->
<signal name="RequestsChanged">
<doc:doc>
<doc:description>
<doc:para>
The latency requests on the system have changed.
</doc:para>
</doc:description>
</doc:doc>
</signal>
</interface>
</node>
|
