UbiquitousOS
/
OpenCloudOS-Kernel
mirror of https://gitee.com/OpenCloudOS/OpenCloudOS-Kernel.git
11
0
Fork 0
Code Issues Projects Releases Wiki Activity

cpufreq: intel_pstate: Documentation: Add references sections 

Add separate refereces sections to the cpufreq.rst and
intel_pstate.rst documents under admin-quide/pm and list the
references to external documentation in there.

Update the ACPI specification URL while at it.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
This commit is contained in:
Rafael J. Wysocki 2019-04-04 00:03:30 +02:00
parent 15ade5d2e7
commit 1120b0f985
2 changed files with 23 additions and 12 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
Documentation/admin-guide/pm/cpufreq.rst
View File

@ -396,8 +396,8 @@ RT or deadline scheduling classes, the governor will increase the frequency to
the allowed maximum (that is, the ``scaling_max_freq`` policy limit). In turn,
if it is invoked by the CFS scheduling class, the governor will use the
Per-Entity Load Tracking (PELT) metric for the root control group of the
given CPU as the CPU utilization estimate (see the `Per-entity load tracking`_
LWN.net article for a description of the PELT mechanism). Then, the new
given CPU as the CPU utilization estimate (see the *Per-entity load tracking*
LWN.net article [1]_ for a description of the PELT mechanism). Then, the new
CPU frequency to apply is computed in accordance with the formula
f = 1.25 * ``f_0`` * ``util`` / ``max``
@ -698,4 +698,8 @@ hardware feature (e.g. all Intel ones), even if the
:c:macro:`CONFIG_X86_ACPI_CPUFREQ_CPB` configuration option is set.
.. _Per-entity load tracking: https://lwn.net/Articles/531853/
References
==========
.. [1] Jonathan Corbet, *Per-entity load tracking*,
https://lwn.net/Articles/531853/

25
Documentation/admin-guide/pm/intel_pstate.rst
View File

@ -20,11 +20,10 @@ you have not done that yet.]
For the processors supported by ``intel_pstate``, the P-state concept is broader
than just an operating frequency or an operating performance point (see the
`LinuxCon Europe 2015 presentation by Kristen Accardi <LCEU2015_>`_ for more
LinuxCon Europe 2015 presentation by Kristen Accardi [1]_ for more
information about that). For this reason, the representation of P-states used
by ``intel_pstate`` internally follows the hardware specification (for details
refer to `Intel® 64 and IA-32 Architectures Software Developer’s Manual
Volume 3: System Programming Guide <SDM_>`_). However, the ``CPUFreq`` core
refer to Intel Software Developer’s Manual [2]_). However, the ``CPUFreq`` core
uses frequencies for identifying operating performance points of CPUs and
frequencies are involved in the user space interface exposed by it, so
``intel_pstate`` maps its internal representation of P-states to frequencies too
@ -561,9 +560,9 @@ or to pin every task potentially sensitive to them to a specific CPU.]
On the majority of systems supported by ``intel_pstate``, the ACPI tables
provided by the platform firmware contain ``_PSS`` objects returning information
that can be used for CPU performance scaling (refer to the `ACPI specification`_
for details on the ``_PSS`` objects and the format of the information returned
by them).
that can be used for CPU performance scaling (refer to the ACPI specification
[3]_ for details on the ``_PSS`` objects and the format of the information
returned by them).
The information returned by the ACPI ``_PSS`` objects is used by the
``acpi-cpufreq`` scaling driver. On systems supported by ``intel_pstate``
@ -728,6 +727,14 @@ P-state is called, the ``ftrace`` filter can be set to to
<idle>-0 [000] ..s. 2537.654843: intel_pstate_set_pstate <-intel_pstate_timer_func
.. _LCEU2015: http://events.linuxfoundation.org/sites/events/files/slides/LinuxConEurope_2015.pdf
.. _SDM: http://www.intel.com/content/www/us/en/architecture-and-technology/64-ia-32-architectures-software-developer-system-programming-manual-325384.html
.. _ACPI specification: http://www.uefi.org/sites/default/files/resources/ACPI_6_1.pdf
References
==========
.. [1] Kristen Accardi, *Balancing Power and Performance in the Linux Kernel*,
http://events.linuxfoundation.org/sites/events/files/slides/LinuxConEurope_2015.pdf
.. [2] *Intel® 64 and IA-32 Architectures Software Developer’s Manual Volume 3: System Programming Guide*,
http://www.intel.com/content/www/us/en/architecture-and-technology/64-ia-32-architectures-software-developer-system-programming-manual-325384.html
.. [3] *Advanced Configuration and Power Interface Specification*,
https://uefi.org/sites/default/files/resources/ACPI_6_3_final_Jan30.pdf