osfmk/man/thread_sample.html

   1 <h2>thread_sample</h2>
   2 <hr>
   3 <p>
   4 <strong>Function</strong> - Perform periodic PC sampling for a thread.
   5 <h3>SYNOPSIS</h3>
   6 <pre>
   7 <strong>kern_return_t   thread_sample</strong>
   8                 <strong>(thread_act_t</strong>                     <var>sample_thread</var>,
   9                  <strong>mach_port_make_send_t</strong>               <var>reply_port</var><strong>);</strong>
  10 </pre>
  11 <h3>PARAMETERS</h3>
  12 <dl>
  13 <p>
  14 <dt> <var>sample_thread</var>
  15 <dd>
  16 [in thread send right]
  17 Thread whose PC is to be sampled
  18 <p>
  19 <dt> <var>reply_port</var>
  20 <dd>
  21 [in sample receive (to be converted to send) right]
  22 Port to which PC
  23 sample buffers are sent.  A value of <strong>MACH_PORT_NULL</strong> stops PC
  24 sampling for the thread.
  25 </dl>
  26 <h3>DESCRIPTION</h3>
  27 <p>
  28 The <strong>thread_sample</strong> function causes the program counter
  29 (PC) of the specified
  30 <var>sample_thread</var> to be sampled periodically (whenever the thread happens to be
  31 running at the time of the kernel's "hardclock" interrupt).
  32 The set of PC sample
  33 values obtained are saved in buffers which are sent to the specified
  34 <var>reply_port</var> in
  35 <strong>receive_samples</strong> messages.
  36 <h3>RETURN VALUES</h3>
  37 <p>
  38 Only generic errors apply.
  39 <h3>RELATED INFORMATION</h3>
  40 <p>
  41 Functions:
  42 <a href="task_sample.html"><strong>task_sample</strong></a>,
  43 <a href="receive_samples.html"><strong>receive_samples</strong></a>.