path: root/Documentation
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authorLinus Torvalds <torvalds@linux-foundation.org>2018-06-29 07:14:41 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2018-06-29 07:14:41 -0700
commit5e4e8c55c9fca8c5e06befc16d56800773fb3128 (patch)
tree2181eef55c7b9ab692cf133e2ec3485f38d057fb /Documentation
parent48a3c64b4649b5b23a4ca756af93b4ee820ff883 (diff)
parente27b4d4a7b987ffa93a5a1249dd83dcb69f8d040 (diff)
Merge tag 'pm-4.18-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull power management fixes from Rafael Wysocki: "These fix up recently added features (the Kryo cpufreq driver and performance states coverage in the generic power domains framework), add missing documentation for a recently added sysfs knob in the intel_pstate driver and fix an error in its documentation. Specifics: - Fix the initialization time error handling in the recently added Kryo cpufreq driver (Dan Carpenter). - Fix up the recently added coverage of performance states in the generic power domains (genpd) framework (Viresh Kumar). - Add missing documentation of the new hwp_dynamic_boost sysfs knob in the intel_pstate driver (Rafael Wysocki). - Fix incorrect sysfs path in the intel_pstate driver documentation (Rafael Wysocki)" * tag 'pm-4.18-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: Documentation: intel_pstate: Describe hwp_dynamic_boost sysfs knob Documentation: admin-guide: intel_pstate: Fix sysfs path PM / Domains: Rename opp_node to np PM / Domains: Fix return value of of_genpd_opp_to_performance_state() cpufreq: qcom-kryo: Fix error handling in probe()
Diffstat (limited to 'Documentation')
1 files changed, 12 insertions, 2 deletions
diff --git a/Documentation/admin-guide/pm/intel_pstate.rst b/Documentation/admin-guide/pm/intel_pstate.rst
index 8b9164990956..8f1d3de449b5 100644
--- a/Documentation/admin-guide/pm/intel_pstate.rst
+++ b/Documentation/admin-guide/pm/intel_pstate.rst
@@ -324,8 +324,7 @@ Global Attributes
``intel_pstate`` exposes several global attributes (files) in ``sysfs`` to
control its functionality at the system level. They are located in the
-``/sys/devices/system/cpu/cpufreq/intel_pstate/`` directory and affect all
+``/sys/devices/system/cpu/intel_pstate/`` directory and affect all CPUs.
Some of them are not present if the ``intel_pstate=per_cpu_perf_limits``
argument is passed to the kernel in the command line.
@@ -379,6 +378,17 @@ argument is passed to the kernel in the command line.
but it affects the maximum possible value of per-policy P-state limits
(see `Interpretation of Policy Attributes`_ below for details).
+ This attribute is only present if ``intel_pstate`` works in the
+ `active mode with the HWP feature enabled <Active Mode With HWP_>`_ in
+ the processor. If set (equal to 1), it causes the minimum P-state limit
+ to be increased dynamically for a short time whenever a task previously
+ waiting on I/O is selected to run on a given logical CPU (the purpose
+ of this mechanism is to improve performance).
+ This setting has no effect on logical CPUs whose minimum P-state limit
+ is directly set to the highest non-turbo P-state or above it.
.. _status_attr: