diff options
Diffstat (limited to 'Documentation/admin-guide/pm/intel_pstate.rst')
| -rw-r--r-- | Documentation/admin-guide/pm/intel_pstate.rst | 18 |
1 files changed, 14 insertions, 4 deletions
diff --git a/Documentation/admin-guide/pm/intel_pstate.rst b/Documentation/admin-guide/pm/intel_pstate.rst index d2b6fda3d67b..8f1d3de449b5 100644 --- a/Documentation/admin-guide/pm/intel_pstate.rst +++ b/Documentation/admin-guide/pm/intel_pstate.rst @@ -145,7 +145,7 @@ feature enabled.] In this mode ``intel_pstate`` registers utilization update callbacks with the CPU scheduler in order to run a P-state selection algorithm, either -``powersave`` or ``performance``, depending on the ``scaling_cur_freq`` policy +``powersave`` or ``performance``, depending on the ``scaling_governor`` policy setting in ``sysfs``. The current CPU frequency information to be made available from the ``scaling_cur_freq`` policy attribute in ``sysfs`` is periodically updated by those utilization update callbacks too. @@ -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 -CPUs. +``/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). +``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`` @@ -410,7 +420,7 @@ argument is passed to the kernel in the command line. That only is supported in some configurations, though (for example, if the `HWP feature is enabled in the processor <Active Mode With HWP_>`_, the operation mode of the driver cannot be changed), and if it is not - supported in the current configuration, writes to this attribute with + supported in the current configuration, writes to this attribute will fail with an appropriate error. Interpretation of Policy Attributes |