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SubjectRe: [PATCH v7 00/14] cpufreq: Introduce a new AMD CPU frequency control mechanism
On Fri, Dec 24, 2021 at 2:05 AM Huang Rui <ray.huang@amd.com> wrote:
>
> Hi all,
>
> Merry Christmas & Happy New Year!
>
> We would like to introduce a new AMD CPU frequency control mechanism as the
> AMD P-State driver for modern AMD Zen based CPU series in Linux Kernel.
> The new mechanism is based on Collaborative processor performance control
> (CPPC) which is finer grain frequency management than legacy ACPI hardware
> P-States. Current AMD CPU platforms are using the ACPI P-states driver to
> manage CPU frequency and clocks with switching only in 3 P-states. AMD
> P-State is to replace the ACPI P-states controls, allows a flexible,
> low-latency interface for the Linux kernel to directly communicate the
> performance hints to hardware.
>
> AMD P-State leverages the Linux kernel governors such as *schedutil*,
> *ondemand*, etc. to manage the performance hints which are provided by CPPC
> hardware functionality. The first version for AMD P-State is to support one
> of the Zen3 processors, and we will support more in future after we verify
> the hardware and SBIOS functionalities.
>
> There are two types of hardware implementations for AMD P-State: one is full
> MSR support and another is shared memory support. It can use
> X86_FEATURE_CPPC feature flag to distinguish the different types.
>
> Using the new AMD P-State method + kernel governors (*schedutil*,
> *ondemand*, ...) to manage the frequency update is the most appropriate
> bridge between AMD Zen based hardware processor and Linux kernel, the
> processor is able to adjust to the most efficiency frequency according to
> the kernel scheduler loading.
>

[cut]

> Actually, the AMD P-State driver doesn't change the physical maximum
> frequency capacity in the processor. But it's able to provide the finer
> grain performance control range instead of legacy 3 P-States. It has a
> better performance and power efficiency than before. We will continue
> optimize AMD P-State function on kernel governors to support different types
> of processors such as mobile latop, performance desktop, and etc.
>

[cut]

>
>
> Huang Rui (11):
> 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
>
> Jinzhou Su (1):
> ACPI: CPPC: Add CPPC enable register function
>
> Mario Limonciello (1):
> ACPI: CPPC: Check present CPUs for determining _CPC is valid
>
> Steven Noonan (1):
> ACPI: CPPC: Implement support for SystemIO registers
>
> Documentation/admin-guide/acpi/cppc_sysfs.rst | 2 +
> Documentation/admin-guide/pm/amd-pstate.rst | 383 +++++++++++
> .../admin-guide/pm/working-state.rst | 1 +
> MAINTAINERS | 7 +
> arch/x86/include/asm/cpufeatures.h | 1 +
> arch/x86/include/asm/msr-index.h | 17 +
> drivers/acpi/cppc_acpi.c | 99 ++-
> 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 | 643 ++++++++++++++++++
> include/acpi/cppc_acpi.h | 5 +
> 13 files changed, 1255 insertions(+), 4 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
>
> --

I'm queuing up this series for 5.17 with the assumption that all of
the comments on patch 2 have been addressed and that Steve will not
hate patch 9.

Thanks!

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