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

<h2>thread_sample</h2>\r<hr>\r<p>\r<strong>Function</strong> - Perform periodic PC sampling for a thread.\r<h3>SYNOPSIS</h3>\r<pre>\r<strong>kern_return_t   thread_sample</strong>\r                <strong>(thread_act_t</strong>                     <var>sample_thread</var>,\r                 <strong>mach_port_make_send_t</strong>               <var>reply_port</var><strong>);</strong>\r</pre>\r<h3>PARAMETERS</h3>\r<dl>\r<p>\r<dt> <var>sample_thread</var> \r<dd>\r[in thread send right]\rThread whose PC is to be sampled\r<p>\r<dt> <var>reply_port</var> \r<dd>\r[in sample receive (to be converted to send) right]\rPort to which PC \rsample buffers are sent.  A value of <strong>MACH_PORT_NULL</strong> stops PC \rsampling for the thread.\r</dl>\r<h3>DESCRIPTION</h3>\r<p>\rThe <strong>thread_sample</strong> function causes the program counter\r(PC) of the specified \r<var>sample_thread</var> to be sampled periodically (whenever the thread happens to be \rrunning at the time of the kernel's "hardclock" interrupt). \rThe set of PC sample \rvalues obtained are saved in buffers which are sent to the specified\r<var>reply_port</var> in \r<strong>receive_samples</strong> messages.\r<h3>RETURN VALUES</h3>\r<p>\rOnly generic errors apply.\r<h3>RELATED INFORMATION</h3>\r<p>\rFunctions:\r<a href="task_sample.html"><strong>task_sample</strong></a>,\r<a href="receive_samples.html"><strong>receive_samples</strong></a>.\r