xnu-4903.221.2.tar.gz

[apple/xnu.git] / osfmk / man / policy_timeshare_info.html

<h2>policy_timeshare_info</h2>
<hr>
<p>
<strong>Structure</strong> - Specifies information associated with the system's Timeshare scheduling policy.
<h3>SYNOPSIS</h3>
<pre>
<strong>struct policy_timeshare_limit</strong>
<strong>{</strong>
       <strong>int</strong>            <var>max_priority</var><strong>;</strong>
<strong>};</strong>

<strong>struct policy_timeshare_base</strong>
<strong>{</strong>
       <strong>int</strong>           <var>base_priority</var><strong>;</strong>
<strong>};</strong>

<strong>struct policy_timeshare_info</strong>
<strong>{</strong>
       <strong>int</strong>            <var>max_priority</var><strong>;</strong>
       <strong>int</strong>           <var>base_priority</var><strong>;</strong>
       <strong>int</strong>            <var>cur_priority</var><strong>;</strong>
       <strong>boolean_t</strong>         <var>depressed</var><strong>;</strong>
       <strong>int</strong>        <var>depress_priority</var><strong>;</strong>
<strong>};</strong>
</pre>
<h3>FIELDS</h3>
<dl>
<dt> <var>max_priority</var>
<dd>
Maximum scheduling priority.
<p>
<dt> <var>base_priority</var>
<dd>
Base scheduling priority.
<p>
<dt> <var>cur_priority</var>
<dd>
Current scheduling priority.
<p>
<dt> <var>depressed</var>
<dd>
True if scheduling priority is depressed.
<p>
<dt> <var>depress_priority</var>
<dd>
Scheduling priority from which depressed.
</dl>
<h3>DESCRIPTION</h3>
<p>
The <strong>policy_timeshare_info</strong> structure defines the timeshare
scheduling policy
information.
Timeshare threads have three priorities associated with them by the system:
<ul>
  <p>
<li>
A maximum priority value which can be raised only via privileged operation 
so that users may not unfairly compete with other users in their processor 
set.  Newly created threads obtain their maximum priority from that of their 
assigned processor set.
     <p>
<li>
A priority value which can be set by the thread to any value up to a
maximum priority.  Newly created threads obtain their priority from their task.
     <p>
<li>
A scheduled priority value which is used to make scheduling decisions for 
the thread.  This value is determined on the basis of the user
priority value by 
the scheduling policy (for time-sharing, this means adding an increment
derived from CPU usage).
</ul>
<h3>RELATED INFORMATION</h3>
<p>
Functions:
<a href="thread_info.html"><strong>thread_info</strong></a>,
<a href="task_info.html"><strong>task_info</strong></a>,
<a href="processor_set_info.html"><strong>processor_set_info</strong></a>,
<a href="P_set_policy_control.html"><strong>processor_set_policy_control</strong></a>,
<a href="P_set_policy_disable.html"><strong>processor_set_policy_disable</strong></a>,
<a href="P_set_policy_enable.html"><strong>processor_set_policy_enable</strong></a>,
<a href="task_policy.html"><strong>task_policy</strong></a>,
<a href="thread_policy.html"><strong>thread_policy</strong></a>,
<a href="thread_set_policy.html"><strong>thread_set_policy</strong></a>.
<p>
Data Structures:
<a href="policy_fifo_info.html"><strong>policy_fifo_info</strong></a>,
<a href="policy_rr_info.html"><strong>policy_rr_info</strong></a>.