[PATCH V5 3/3] Documentation: amd-pstate: Add unit test introduction

From: Meng Li
Date: Wed May 04 2022 - 22:30:40 EST

Introduce the AMD P-State unit test module design and implementation.

Signed-off-by: Meng Li <li.meng@xxxxxxx>
---
Documentation/admin-guide/pm/amd-pstate.rst | 85 +++++++++++++++++++++
1 file changed, 85 insertions(+)

diff --git a/Documentation/admin-guide/pm/amd-pstate.rst b/Documentation/admin-guide/pm/amd-pstate.rst
index 83b58eb4ab4d..dbcc50e973f9 100644
--- a/Documentation/admin-guide/pm/amd-pstate.rst
+++ b/Documentation/admin-guide/pm/amd-pstate.rst
@@ -182,6 +182,7 @@ to the ``struct sugov_cpu`` that the utilization update belongs to.
Then, ``amd-pstate`` updates the desired performance according to the CPU
scheduler assigned.

+.. _processor_support:

Processor Support
=======================
@@ -282,6 +283,8 @@ efficiency frequency management method on AMD processors.
Kernel Module Options for ``amd-pstate``
=========================================

+.. _shared_mem:
+
``shared_mem``
Use a module param (shared_mem) to enable related processors manually with
**amd_pstate.shared_mem=1**.
@@ -393,6 +396,85 @@ about part of the output. ::
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

+Unit Tests for amd-pstate
+-------------------------
+
+``amd-pstate-ut`` is a test module for testing the ``amd-pstate`` driver.
+
+ * It can help all users to verify their processor support (SBIOS/Firmware or Hardware).
+
+ * Kernel can have a basic function test to avoid the kernel regression during the update.
+
+ * We can introduce more functional or performance tests to align the result together, it will benefit power and performance scale optimization.
+
+1. Test case decriptions
+
+ +---------+--------------------------------+------------------------------------------------------------------------------------+
+ | Index | Functions | Description |
+ +=========+================================+====================================================================================+
+ | 0 | aput_acpi_cpc || Check whether the _CPC object is present in SBIOS. |
+ | | || |
+ | | || The detail refer to `Processor Support <processor_support_>`_. |
+ +---------+--------------------------------+------------------------------------------------------------------------------------+
+ | 1 | aput_check_enabled || Check whether AMD P-State is enabled. |
+ | | || |
+ | | || AMD P-States and ACPI hardware P-States always can be supported in one processor. |
+ | | | But AMD P-States has the higher priority and if it is enabled with |
+ | | | :c:macro:`MSR_AMD_CPPC_ENABLE` or ``cppc_set_enable``, it will respond to the |
+ | | | request from AMD P-States. |
+ +---------+--------------------------------+------------------------------------------------------------------------------------+
+ | 2 | aput_check_perf || Check if the each performance values are reasonable. |
+ | | || highest_perf >= nominal_perf > lowest_nonlinear_perf > lowest_perf > 0. |
+ +---------+--------------------------------+------------------------------------------------------------------------------------+
+ | 3 | aput_check_freq || Check if the each frequency values and max freq when set support boost mode |
+ | | | are reasonable. |
+ | | || max_freq >= nominal_freq > lowest_nonlinear_freq > min_freq > 0 |
+ | | || If boost is not active but supported, this maximum frequency will be larger than |
+ | | | the one in ``cpuinfo``. |
+ +---------+--------------------------------+------------------------------------------------------------------------------------+
+
+#. How to execute the tests
+
+ We use test module in the kselftest frameworks to implement it.
+ We create amd-pstate-ut module and tie it into kselftest.(for
+ details refer to Linux Kernel Selftests [4]_).
+
+ 1. Build ::
+
+ jasminemeng@jasmine-meng:~/amd-brahma$ cd linux
+ jasminemeng@jasmine-meng:~/amd-brahma/linux$ make modules M=tools/testing/selftests/amd-pstate/amd-pstate-ut
+ CC [M] tools/testing/selftests/amd-pstate/amd-pstate-ut/amd-pstate-ut.o
+ MODPOST tools/testing/selftests/amd-pstate/amd-pstate-ut/Module.symvers
+ CC [M] tools/testing/selftests/amd-pstate/amd-pstate-ut/amd-pstate-ut.mod.o
+ LD [M] tools/testing/selftests/amd-pstate/amd-pstate-ut/amd-pstate-ut.ko
+ BTF [M] tools/testing/selftests/amd-pstate/amd-pstate-ut/amd-pstate-ut.ko
+ jasminemeng@jasmine-meng:~/amd-brahma/linux$ make -C tools/testing/selftests
+
+ #. Installation & Steps ::
+
+ jasmine@jasmine-meng:~/amd-brahma/linux$ make -C tools/testing/selftests install INSTALL_PATH=~/kselftest
+ jasmine@jasmine-meng:~$ sudo ./kselftest/run_kselftest.sh -c amd-pstate
+ TAP version 13
+ 1..1
+ # selftests: amd-pstate: amd-pstate-ut.sh
+ # amd-pstate-ut: ok
+ ok 1 selftests: amd-pstate: amd-pstate-ut.sh
+
+ #. Results ::
+
+ jasmine@jasmine-meng:~$ dmesg | grep "amd-pstate-ut" | tee log.txt
+ [76697.480217] amd-pstate-ut: loaded.
+ [76697.480222] amd-pstate-ut: ****** Begin 1 acpi_cpc_valid ******
+ [76697.480227] amd-pstate-ut: ****** End 1 acpi_cpc_valid ******
+ [76697.480228] amd-pstate-ut: ****** Begin 2 check_enabled ******
+ [76697.480253] amd-pstate-ut: ****** End 2 check_enabled ******
+ [76697.480255] amd-pstate-ut: ****** Begin 3 check_perf ******
+ [76697.480554] amd-pstate-ut: ****** End 3 check_perf ******
+ [76697.480556] amd-pstate-ut: ****** Begin 4 check_freq ******
+ [76697.480558] amd-pstate-ut: ****** End 4 check_freq ******
+ [76697.480559] amd-pstate-ut: all 4 tests passed
+ [76697.482507] amd-pstate-ut: unloaded.
+

Reference
===========
@@ -405,3 +487,6 @@ Reference

.. [3] Processor Programming Reference (PPR) for AMD Family 19h Model 51h, Revision A1 Processors
https://www.amd.com/system/files/TechDocs/56569-A1-PUB.zip
+
+.. [4] Linux Kernel Selftests,
+ https://www.kernel.org/doc/html/latest/dev-tools/kselftest.html
--
2.25.1