xnu-4903.221.2.tar.gz

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

<h2>policy_fifo_info</h2>
<hr>
<p>
<strong>Structure</strong> - Specifies information associated with the system's First-In-First-Out scheduling policy.
<h3>SYNOPSIS</h3>
<pre>
<strong>struct policy_fifo_limit</strong>
<strong>{</strong>
       <strong>int</strong>                    <var>max_priority</var><strong>;</strong>
<strong>};</strong>

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

<strong>struct policy_fifo_info</strong>
<strong>{</strong>
       <strong>int</strong>                   <var>max_priority</var><strong>;</strong>
       <strong>int</strong>                  <var>base_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>
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_fifo_info</strong> structure defines the first-in-first-out
scheduling policy information.
FIFO threads have two 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.
</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_rr_info.html"><strong>policy_rr_info</strong></a>,
<a href="policy_timeshare_info.html"><strong>policy_timeshare_info</strong></a>.