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authorRafael J. Wysocki <rafael.j.wysocki@intel.com>2018-06-26 17:20:43 +0200
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2018-06-27 13:02:06 +0200
commit649f53a3e4cf6873741673b9271275e484c56194 (patch)
treef6b5ddbedde4e7ea17c302413b87019e51b37d59
parent9e421b8fffb92bfd1c274f1deae611a6ab99d8a7 (diff)
downloadlinux-649f53a3e4cf6873741673b9271275e484c56194.tar.bz2
Documentation: intel_pstate: Describe hwp_dynamic_boost sysfs knob
Document the recently introduced hwp_dynamic_boost sysfs knob allowing user space to tell intel_pstate to use iowait boosting in the active mode with HWP enabled (to improve performance). Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
-rw-r--r--Documentation/admin-guide/pm/intel_pstate.rst11
1 files changed, 11 insertions, 0 deletions
diff --git a/Documentation/admin-guide/pm/intel_pstate.rst b/Documentation/admin-guide/pm/intel_pstate.rst
index d74fb572f6cc..8f1d3de449b5 100644
--- a/Documentation/admin-guide/pm/intel_pstate.rst
+++ b/Documentation/admin-guide/pm/intel_pstate.rst
@@ -378,6 +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).
+``hwp_dynamic_boost``
+ 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:
``status``