.. index:: pair: group; Tune clock frequency
.. _doxid-group__ptp-adj__frequency:

Tune clock frequency
====================

.. toctree::
	:hidden:

Check that frequency can be tuned for PTP device associated with the tested network interface.

Scenarios: X3-PTP004, X3-PTP005.



#. Find out PTP device associated with the IUT interface, call **open()** to get its FD.

#. Call **clock_adjtime()** to check whether current frequency offset is zero.

#. Use **clock_adjtime()** to tune PTP device frequency according to **freq**. With help of **clock_gettime()** check whether the clock works as expected after that.

#. Use **clock_adjtime()** to undo the previously made change. With help of **clock_gettime()** check whether the clock works as expected after that.

Yurij Plotnikov `Yurij.Plotnikov@arknetworks.am <mailto:Yurij.Plotnikov@arknetworks.am>`__



.. rubric:: Parameters:

.. list-table::
	:widths: 20 80

	*
		- env

		- 
		  Testing environment:
		  
		  * :ref:`env.peer2peer <doxid-group__env-peer2peer>`

	*
		- freq

		- Frequency offset, in parts per million

	*
		- min_sleep

		- Minimum time to sleep between clock_gettime() calls when checking how the clock advances, seconds

	*
		- max_sleep

		- Maximum time to sleep between clock_gettime() calls when checking how the clock advances, seconds