3 files changed, 87 insertions, 0 deletions
diff --git a/Documentation/admin-guide/pm/amd-pstate.rst b/Documentation/admin-guide/pm/amd-pstate.rst
index 2f066df4ee9c..1923cb25073b 100644
--- a/Documentation/admin-guide/pm/amd-pstate.rst
+++ b/Documentation/admin-guide/pm/amd-pstate.rst
@@ -369,6 +369,32 @@ governor (for the policies it is attached to), or by the ``CPUFreq`` core (for t
 policies with other scaling governors).
 
 
+Tracer Tool
+-------------
+
+``amd_pstate_tracer.py`` can record and parse ``amd-pstate`` trace log, then
+generate performance plots. This utility can be used to debug and tune the
+performance of ``amd-pstate`` driver. The tracer tool needs to import intel
+pstate tracer.
+
+Tracer tool located in ``linux/tools/power/x86/amd_pstate_tracer``. It can be
+used in two ways. If trace file is available, then directly parse the file
+with command ::
+
+ ./amd_pstate_trace.py [-c cpus] -t <trace_file> -n <test_name>
+
+Or generate trace file with root privilege, then parse and plot with command ::
+
+ sudo ./amd_pstate_trace.py [-c cpus] -n <test_name> -i <interval> [-m kbytes]
+
+The test result can be found in ``results/test_name``. Following is the example
+about part of the output. ::
+
+ common_cpu  common_secs  common_usecs  min_perf  des_perf  max_perf  freq    mperf   apef    tsc       load   duration_ms  sample_num  elapsed_time  common_comm
+ CPU_005     712          116384        39        49        166       0.7565  9645075 2214891 38431470  25.1   11.646       469         2.496         kworker/5:0-40
+ CPU_006     712          116408        39        49        166       0.6769  8950227 1839034 37192089  24.06  11.272       470         2.496         kworker/6:0-1264
+
+
 Reference
 ===========
 
diff --git a/Documentation/admin-guide/pm/intel_uncore_frequency_scaling.rst b/Documentation/admin-guide/pm/intel_uncore_frequency_scaling.rst
new file mode 100644
index 000000000000..09169d935835
--- /dev/null
+++ b/Documentation/admin-guide/pm/intel_uncore_frequency_scaling.rst
@@ -0,0 +1,60 @@
+.. SPDX-License-Identifier: GPL-2.0
+.. include:: <isonum.txt>
+
+==============================
+Intel Uncore Frequency Scaling
+==============================
+
+:Copyright: |copy| 2022 Intel Corporation
+
+:Author: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
+
+Introduction
+------------
+
+The uncore can consume significant amount of power in Intel's Xeon servers based
+on the workload characteristics. To optimize the total power and improve overall
+performance, SoCs have internal algorithms for scaling uncore frequency. These
+algorithms monitor workload usage of uncore and set a desirable frequency.
+
+It is possible that users have different expectations of uncore performance and
+want to have control over it. The objective is similar to allowing users to set
+the scaling min/max frequencies via cpufreq sysfs to improve CPU performance.
+Users may have some latency sensitive workloads where they do not want any
+change to uncore frequency. Also, users may have workloads which require
+different core and uncore performance at distinct phases and they may want to
+use both cpufreq and the uncore scaling interface to distribute power and
+improve overall performance.
+
+Sysfs Interface
+---------------
+
+To control uncore frequency, a sysfs interface is provided in the directory:
+`/sys/devices/system/cpu/intel_uncore_frequency/`.
+
+There is one directory for each package and die combination as the scope of
+uncore scaling control is per die in multiple die/package SoCs or per
+package for single die per package SoCs. The name represents the
+scope of control. For example: 'package_00_die_00' is for package id 0 and
+die 0.
+
+Each package_*_die_* contains the following attributes:
+
+``initial_max_freq_khz``
+	Out of reset, this attribute represent the maximum possible frequency.
+	This is a read-only attribute. If users adjust max_freq_khz,
+	they can always go back to maximum using the value from this attribute.
+
+``initial_min_freq_khz``
+	Out of reset, this attribute represent the minimum possible frequency.
+	This is a read-only attribute. If users adjust min_freq_khz,
+	they can always go back to minimum using the value from this attribute.
+
+``max_freq_khz``
+	This attribute is used to set the maximum uncore frequency.
+
+``min_freq_khz``
+	This attribute is used to set the minimum uncore frequency.
+
+``current_freq_khz``
+	This attribute is used to get the current uncore frequency.
diff --git a/Documentation/admin-guide/pm/working-state.rst b/Documentation/admin-guide/pm/working-state.rst
index 5d2757e2de65..ee45887811ff 100644
--- a/Documentation/admin-guide/pm/working-state.rst
+++ b/Documentation/admin-guide/pm/working-state.rst
@@ -15,3 +15,4 @@ Working-State Power Management
    cpufreq_drivers
    intel_epb
    intel-speed-select
+   intel_uncore_frequency_scaling