ACK: [Jammy] [PATCH 00/16][SRU][OEM-5.14/Jammy] Support AMD P-State cpufreq control mechanism

[Tim Gardner]

Acked-by: Tim Gardner <tim.gardner at canonical.com>

On 4/7/22 20:38, You-Sheng Yang wrote:
> BugLink: https://bugs.launchpad.net/bugs/1956509
> 
> [Impact]
> 
> AMD P-State CPU performance scaling driver not yet supported on AMD Zen
> based CPU series.
> 
> [Fix]
> 
> Mainline commits starting at commit d341db8f48ea ("x86/cpufeatures: Add
> AMD Collaborative Processor Performance Control feature flag") from v5.17.
> 
> Even this committed, the defconfig will build it as module, and that
> prevents AMD P-State driver from actually taking effect. Therefore an
> additional fix to the kernel configs is necessary.
> 
> [Test Case]
> 
> $ sudo cpupower frequency-info
> analyzing CPU 0:
>    driver: amd-pstate
>    CPUs which run at the same hardware frequency: 0
>    CPUs which need to have their frequency coordinated by software: 0
>    maximum transition latency: 131 us
>    hardware limits: 400 MHz - 3.10 GHz
>    available cpufreq governors: conservative ondemand userspace powersave
> performance schedutil
>    current policy: frequency should be within 1.60 GHz and 3.10 GHz.
>                    The governor "ondemand" may decide which speed to use
>                    within this range.
>    current CPU frequency: Unable to call hardware
>    current CPU frequency: 1.59 GHz (asserted by call to kernel)
>    boost state support:
>      Supported: yes
>      Active: yes
>      Boost States: 0
>      Total States: 3
>      Pstate-P0: 3100MHz
>      Pstate-P1: 1800MHz
>      Pstate-P2: 1600MHz
> 
> [Where problems could occur]
> 
> The CPPC feature is implemented in two ways depending on underlying HW
> details for the APU/CPU:
> * Dedicated MSR
> * Shared memory
> 
> The metrics used to measure power/performance efficiency don't show any
> improvement on the designs that use shared memory. They do show
> improvements in the MSR designs.
> 
> So the code will only enable it by default on the MSR implementation.
> 
> [Other Info]
> 
> Althought the v5.17 kernel and newer should have already this committed,
> an additional fix to the kernel configs is necessary, and
> unstable/oem-5.17 are also nominated (in a separate thread for they don't
> need other parts but the config).
> 
> Huang Rui (12):
>    x86/cpufeatures: Add AMD Collaborative Processor Performance Control
>      feature flag
>    x86/msr: Add AMD CPPC MSR definitions
>    cpufreq: amd-pstate: Introduce a new AMD P-State driver to support
>      future processors
>    cpufreq: amd-pstate: Add fast switch function for AMD P-State
>    cpufreq: amd-pstate: Introduce the support for the processors with
>      shared memory solution
>    cpufreq: amd-pstate: Add trace for AMD P-State module
>    cpufreq: amd-pstate: Add boost mode support for AMD P-State
>    cpufreq: amd-pstate: Add AMD P-State frequencies attributes
>    cpufreq: amd-pstate: Add AMD P-State performance attributes
>    Documentation: amd-pstate: Add AMD P-State driver introduction
>    MAINTAINERS: Add AMD P-State driver maintainer entry
>    cpufreq: amd-pstate: Fix Kconfig dependencies for AMD P-State
> 
> Jinzhou Su (1):
>    ACPI: CPPC: Add CPPC enable register function
> 
> Steven Noonan (1):
>    ACPI: CPPC: Implement support for SystemIO registers
> 
> Yang Li (1):
>    cpufreq: amd-pstate: Fix struct amd_cpudata kernel-doc comment
> 
> You-Sheng Yang (1):
>    UBUNTU: [Config] enable X86_AMD_PSTATE as built-in on amd64
> 
>   Documentation/admin-guide/acpi/cppc_sysfs.rst |   2 +
>   Documentation/admin-guide/pm/amd-pstate.rst   | 382 +++++++++++
>   .../admin-guide/pm/working-state.rst          |   1 +
>   MAINTAINERS                                   |   7 +
>   arch/x86/include/asm/cpufeatures.h            |   1 +
>   arch/x86/include/asm/msr-index.h              |  17 +
>   debian.oem/config/annotations                 |   1 +
>   debian.oem/config/config.common.ubuntu        |   1 +
>   drivers/acpi/cppc_acpi.c                      |  97 ++-
>   drivers/cpufreq/Kconfig.x86                   |  17 +
>   drivers/cpufreq/Makefile                      |   5 +
>   drivers/cpufreq/amd-pstate-trace.c            |   2 +
>   drivers/cpufreq/amd-pstate-trace.h            |  77 +++
>   drivers/cpufreq/amd-pstate.c                  | 645 ++++++++++++++++++
>   include/acpi/cppc_acpi.h                      |   5 +
>   15 files changed, 1257 insertions(+), 3 deletions(-)
>   create mode 100644 Documentation/admin-guide/pm/amd-pstate.rst
>   create mode 100644 drivers/cpufreq/amd-pstate-trace.c
>   create mode 100644 drivers/cpufreq/amd-pstate-trace.h
>   create mode 100644 drivers/cpufreq/amd-pstate.c
> 

-- 
-----------
Tim Gardner
Canonical, Inc