[PATCH v10 0/8] AMD Pstate Fixes And Enhancements

Perry Yuan
2024-03-25T03:04:10Z

The patch series adds some fixes and enhancements to the AMD pstate
driver.

It enables CPPC v2 for certain processors in the family 17H, as
requested by TR40 processor users who expect improved performance and lower system
temperature.

changes latency and delay values to be read from platform firmware
firstly
for more accurate timing.

A new quirk is introduced for supporting amd-pstate on legacy processors which either lack CPPC capability,
or only only have CPPC v2 capability

Testing done with one APU system while cpb boost on:

amd_pstate_lowest_nonlinear_freq:1701000
amd_pstate_max_freq:3501000
cpuinfo_max_freq:3501000
cpuinfo_min_freq:400000
scaling_cur_freq:3084836
scaling_max_freq:3501000
scaling_min_freq:400000

analyzing CPU 6:
driver: amd-pstate-epp
CPUs which run at the same hardware frequency: 6
CPUs which need to have their frequency coordinated by software: 6
maximum transition latency: Cannot determine or is not supported.
hardware limits: 400 MHz - 3.50 GHz
available cpufreq governors: performance powersave
current policy: frequency should be within 400 MHz and 3.50 GHz.
The governor "powersave" may decide which speed to use
within this range.
current CPU frequency: Unable to call hardware
current CPU frequency: 3.50 GHz (asserted by call to kernel)
boost state support:
Supported: yes
Active: yes
AMD PSTATE Highest Performance: 255. Maximum Frequency: 3.50 GHz.
AMD PSTATE Nominal Performance: 204. Nominal Frequency: 2.80 GHz.
AMD PSTATE Lowest Non-linear Performance: 124. Lowest Non-linear Frequency: 1.70 GHz.
AMD PSTATE Lowest Performance: 30. Lowest Frequency: 400 MHz.

I would greatly appreciate any feedbacks.
Thank you!
Perry.

Changes from v9:
* pick review by flag from Meng Li
* pick test by flag from Ugwekar Dhananjay
* picl review by flag from Gautham R. Shenoy

Changes from v8:
* add commit log for patch 1 and patch 2 (Rafael)
* add missing Perry signed-off-by for new patches #1,#2,#4 (Rafael)
* rebased to latest linux-pm/bleeding-edge

Changes from v7:
* Gautham helped to invole some new improved patches into the patchset.
* Adds comments for cpudata->{min,max}_limit_{perf,freq}, variables [New Patch].
* Clarifies that the units for cpudata->*_freq is in khz via comments [New Patch].
* Implements the unified computation of all cpudata->*_freq
* v7 Patch 2/6 was dropped which is not needed any more
* moved the quirk check to the amd_pstate_get_freq() function
* pick up RB flags from Gautham
* After the cleanup in patch 3, we don't need the helpers
amd_get_{min,max,nominal,lowest_nonlinear}_freq(). This
patch removes it [New Patch].
* testing done on APU system as well, no regression found.

Changes from v6:
* add one new patch to initialize capabilities in
amd_pstate_init_perf which can avoid duplicate cppc capabilities read
the change has been tested on APU system.
* pick up RB flags from Gautham
* drop the patch 1/6 which has been merged by Rafael

Changes from v5:
* rebased to linux-pm v6.8
* pick up RB flag from for patch 6(Mario)

Changes from v4:
* improve the dmi matching rule with zen2 flag only

Changes from v3:
* change quirk matching broken BIOS with family/model ID and Zen2
flag to fix the CPPC definition issue
* fix typo in quirk

Changes from v2:
* change quirk matching to BIOS version and release (Mario)
* pick up RB flag from Mario

Changes from v1:
* pick up the RB flags from Mario
* address review comment of patch #6 for amd_get_nominal_freq()
* rebased the series to linux-pm/bleeding-edge v6.8.0-rc2
* update debug log for patch #5 as Mario suggested.
* fix some typos and format problems
* tested on 7950X platform

V1: https://lore.kernel.org/lkml/63c2b3d7-083a-4daa-ba40-629b3223a92d@mailbox.org/
V2: https://lore.kernel.org/all/cover.1706863981.git.perry.yuan@amd.com/
v3: https://lore.kernel.org/lkml/cover.1707016927.git.perry.yuan@amd.com/
v4: https://lore.kernel.org/lkml/cover.1707193566.git.perry.yuan@amd.com/
v5: https://lore.kernel.org/lkml/cover.1707273526.git.perry.yuan@amd.com/
v6: https://lore.kernel.org/lkml/cover.1707363758.git.perry.yuan@amd.com/
v7: https://lore.kernel.org/lkml/cover.1710323410.git.perry.yuan@amd.com/
v8: https://lore.kernel.org/lkml/cover.1710754409.git.perry.yuan@amd.com/
v9: https://lore.kernel.org/lkml/cover.1710836407.git.perry.yuan@amd.com/

Gautham R. Shenoy (3):
cpufreq: amd-pstate: Document *_limit_* fields in struct amd_cpudata
cpufreq: amd-pstate: Document the units for freq variables in
amd_cpudata
cpufreq: amd-pstate: Remove
amd_get_{min,max,nominal,lowest_nonlinear}_freq()

Perry Yuan (5):
cpufreq: amd-pstate: Unify computation of
{max,min,nominal,lowest_nonlinear}_freq
cpufreq: amd-pstate: Bail out if min/max/nominal_freq is 0
cpufreq: amd-pstate: get transition delay and latency value from ACPI
tables
cppc_acpi: print error message if CPPC is unsupported
cpufreq: amd-pstate: Add quirk for the pstate CPPC capabilities
missing

drivers/acpi/cppc_acpi.c | 4 +-
drivers/cpufreq/amd-pstate.c | 257 +++++++++++++++++++++--------------
include/linux/amd-pstate.h | 20 ++-
3 files changed, 174 insertions(+), 107 deletions(-)

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2.34.1