:orphan:

.. title:: APIC_TIMER_TSC

.. option:: CONFIG_APIC_TIMER_TSC

*Use invariant TSC for sys\_clock\_cycle\_get\_32()*

Type: ``bool``

Help
====

.. code-block:: none

    If your CPU supports invariant TSC, and you know the ratio of the
    TSC frequency to CONFIG_SYS_CLOCK_HW_CYCLES_PER_SEC (the local APIC
    timer frequency), then enable this for a much faster and more
    accurate sys_clock_cycle_get_32().

Direct dependencies
===================

(\ :option:`APIC_TIMER <CONFIG_APIC_TIMER>` && \ :option:`SOC_APOLLO_LAKE <CONFIG_SOC_APOLLO_LAKE>`) || \ :option:`APIC_TIMER <CONFIG_APIC_TIMER>`

*(Includes any dependencies from ifs and menus.)*

Default
=======

- y

Kconfig definitions
===================



At ``<Zephyr SoC>/x86/apollo_lake/Kconfig.defconfig:20``

Included via ``Kconfig:8`` → ``Kconfig.zephyr:19`` → ``<BuildDir>/kconfig/Kconfig.soc.defconfig:1``

Menu path: (Top)

.. code-block:: kconfig

    config APIC_TIMER_TSC
    	bool
    	default y
    	depends on APIC_TIMER && SOC_APOLLO_LAKE

----

At ``<Zephyr Driver>/timer/Kconfig:35``

Included via ``Kconfig:8`` → ``Kconfig.zephyr:32`` → ``<Zephyr Driver>/Kconfig:28``

Menu path: (Top) → Device Drivers → Timer Drivers → New local APIC timer

.. code-block:: kconfig

    config APIC_TIMER_TSC
    	bool "Use invariant TSC for sys_clock_cycle_get_32()"
    	depends on APIC_TIMER
    	help
    	  If your CPU supports invariant TSC, and you know the ratio of the
    	  TSC frequency to CONFIG_SYS_CLOCK_HW_CYCLES_PER_SEC (the local APIC
    	  timer frequency), then enable this for a much faster and more
    	  accurate sys_clock_cycle_get_32().

*(The 'depends on' condition includes propagated dependencies from ifs and menus.)*