[lkml]   [2019]   [Jul]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
Subject[PATCHv3 0/6] CPPC optional registers AMD support
CPPC (Collaborative Processor Performance Control) offers optional
registers which can be used to tune the system based on energy and/or
performance requirements.

Newer AMD processors (>= Family 17h) add support for a subset of these
optional CPPC registers, based on ACPI v6.1.

The following are the supported CPPC registers for which sysfs entries
are created:
* enable (NEW)
* max_perf (NEW)
* min_perf (NEW)
* energy_perf
* lowest_perf
* nominal_perf
* desired_perf (NEW)
* feedback_ctrs
* auto_sel_enable (NEW)
* lowest_nonlinear_perf

First, update cppc_acpi to create sysfs entries only when the optional
registers are known to be supported.

Next, a new CPUFreq driver is introduced to enable the OSPM and the userspace
to access the newly supported registers through sysfs entries found in

This new CPUFreq driver can only be used by providing a module parameter,

The purpose of exposing the registers via the amd-cpufreq sysfs entries is to
allow the userspace to:
* Tweak the values to fit its workload.
* Apply a profile from AMD's optimization guides.

Profiles will be documented in the performance/optimization guides.

* AMD systems will not have a policy applied in the kernel at this time.

* Create a linux userspace tool that will help users generate a CPPC profile
for their target workload.
* Create a general CPPC policy in the kernel.

* Add macro to ensure BUFFER only registers have BUFFER type.
* Add support macro to make the right check based on register type.
* Remove support checks for registers which are mandatory.

* Introduce new amd-cpufreq driver which will have priority over acpi-cpufreq.
* Move new sysfs entries creation to amd-cpufreq.

Janakarajan Natarajan (3):
acpi/cppc: Add macros for CPPC register checks
acpi/cppc: Ensure only supported CPPC sysfs entries are created
drivers/cpufreq: Add a CPUFreq driver for AMD processors (Fam17h and

Yazen Ghannam (3):
acpi/cppc: Rework cppc_set_perf() to use cppc_regs index
acpi/cppc: Add support for optional CPPC registers
acpi/cppc: Add support for CPPC Enable register

drivers/acpi/cppc_acpi.c | 244 ++++++++++++++++++++++++++++-----
drivers/cpufreq/Kconfig.x86 | 14 ++
drivers/cpufreq/Makefile | 4 +-
drivers/cpufreq/amd-cpufreq.c | 233 +++++++++++++++++++++++++++++++
drivers/cpufreq/cppc_cpufreq.c | 6 +-
include/acpi/cppc_acpi.h | 11 +-
6 files changed, 474 insertions(+), 38 deletions(-)
create mode 100644 drivers/cpufreq/amd-cpufreq.c


 \ /
  Last update: 2019-07-10 20:37    [W:0.088 / U:2.648 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site