Re: [PATCH v11 00/11] Implement AMD Pstate EPP Driver

[Huang Rui]

On Wed, Jan 18, 2023 at 03:51:59PM +0800, Yuan, Perry wrote:
> Hi all,
> 
> This patchset implements one new AMD CPU frequency driver
> `amd-pstate-epp` instance for better performance and power control.
> CPPC has a parameter called energy preference performance (EPP).
> The EPP is used in the CCLK DPM controller to drive the frequency that a core
> is going to operate during short periods of activity.
> EPP values will be utilized for different OS profiles (balanced, performance, power savings).
> 
> AMD Energy Performance Preference (EPP) provides a hint to the hardware
> if software wants to bias toward performance (0x0) or energy efficiency (0xff)
> The lowlevel power firmware will calculate the runtime frequency according to the EPP preference 
> value. So the EPP hint will impact the CPU cores frequency responsiveness.
> 
> We use the RAPL interface with "perf" tool to get the energy data of the package power.
> Performance Per Watt (PPW) Calculation:
> 
> The PPW calculation is referred by below paper:
> https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fsoftware.intel.com%2Fcontent%2Fdam%2Fdevelop%2Fexternal%2Fus%2Fen%2Fdocuments%2Fperformance-per-what-paper.pdf&data=04%7C01%7CPerry.Yuan%40amd.com%7Cac66e8ce98044e9b062708d9ab47c8d8%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637729147708574423%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=TPOvCE%2Frbb0ptBreWNxHqOi9YnVhcHGKG88vviDLb00%3D&reserved=0
> 
> Below formula is referred from below spec to measure the PPW:
> 
> (F / t) / P = F * t / (t * E) = F / E,
> 
> "F" is the number of frames per second.
> "P" is power measured in watts.
> "E" is energy measured in joules.
> 
> Gitsouce Benchmark Data on ROME Server CPU
> +------------------------------+------------------------------+------------+------------------+
> | Kernel Module                | PPW (1 / s * J)              |Energy(J) | PPW Improvement (%)|
> +==============================+==============================+============+==================+
> | acpi-cpufreq:schedutil       | 5.85658E-05                  | 17074.8    | base             |
> +------------------------------+------------------------------+------------+------------------+
> | acpi-cpufreq:ondemand        | 5.03079E-05                  | 19877.6    | -14.10%          |
> +------------------------------+------------------------------+------------+------------------+
> | acpi-cpufreq:performance     | 5.88132E-05                  | 17003      | 0.42%            |
> +------------------------------+------------------------------+------------+------------------+
> | amd-pstate:ondemand          | 4.60295E-05                  | 21725.2    | -21.41%          |
> +------------------------------+------------------------------+------------+------------------+
> | amd-pstate:schedutil         | 4.70026E-05                  | 21275.4    | -19.7%           |
> +------------------------------+------------------------------+------------+------------------+
> | amd-pstate:performance       | 5.80094E-05                  | 17238.6    | -0.95%           |
> +------------------------------+------------------------------+------------+------------------+
> | EPP:performance              | 5.8292E-05                   | 17155      | -0.47%           |
> +------------------------------+------------------------------+------------+------------------+
> | EPP: balance performance:    | 6.71709E-05                  | 14887.4    | 14.69%           |
> +------------------------------+------------------------------+------------+------------------+
> | EPP:power                    | 6.66951E-05                  | 4993.6     | 13.88%           |
> +------------------------------+------------------------------+------------+------------------+
> 
> Tbench Benchmark Data on ROME Server CPU
> +---------------------------------------------+-------------------+--------------+-------------+------------------+
> | Kernel Module                               | PPW MB / (s * J)  |Throughput(MB/s)| Energy (J)|PPW Improvement(%)|
> +=============================================+===================+==============+=============+==================+
> | acpi_cpufreq: schedutil                     | 46.39             | 17191        | 37057.3     | base             |
> +---------------------------------------------+-------------------+--------------+-------------+------------------+
> | acpi_cpufreq: ondemand                      | 51.51             | 19269.5      | 37406.5     | 11.04 %          |
> +---------------------------------------------+-------------------+--------------+-------------+------------------+
> | acpi_cpufreq: performance                   | 45.96             | 17063.7      | 37123.7     | -0.74 %          |
> +---------------------------------------------+-------------------+--------------+-------------+------------------+
> | EPP:powersave: performance(0)               | 54.46             | 20263.1      | 37205       | 17.87 %          |
> +---------------------------------------------+-------------------+--------------+-------------+------------------+
> | EPP:powersave: balance performance          | 55.03             | 20481.9      | 37221.5     | 19.14 %          |
> +---------------------------------------------+-------------------+--------------+-------------+------------------+
> | EPP:powersave: balance_power                | 54.43             | 20245.9      | 37194.2     | 17.77 %          |
> +---------------------------------------------+-------------------+--------------+-------------+------------------+
> | EPP:powersave: power(255)                   | 54.26             | 20181.7      | 37197.4     | 17.40 %          |
> +---------------------------------------------+-------------------+--------------+-------------+------------------+
> | amd-pstate: schedutil                       | 48.22             | 17844.9      | 37006.6     | 3.80 %           |
> +---------------------------------------------+-------------------+--------------+-------------+------------------+
> | amd-pstate: ondemand                        | 61.30             | 22988        | 37503.4     | 33.72 %          |
> +---------------------------------------------+-------------------+--------------+-------------+------------------+
> | amd-pstate: performance                     | 54.52             | 20252.6      | 37147.8     | 17.81 %          |
> +---------------------------------------------+-------------------+--------------+-------------+------------------+
> 
> changes from v10:
>  * pick up all new ack flas added by Ray
>  * pick up Review-By flag added by Wyes
>  * pick up Test-By flags added by Wyes
>  * move the EPP macro definition to amd_pstate.h and drop the common
>    code patch
>  * add amd_perf_ctl_reset() in epp init code as well
>  * As the warning which reminded by 0day, change amd_pstate_get_epp(cpudata, value)
>    to amd_pstate_get_epp(cpudata, 0).
> 
> changes from v8:
>  * drive all the feedbacks from Mario and change the codes in this
>   version
>  * drive all the feedbacks from Ray and change the codes in this
>   version
>  * pick up all the R-B flags from Mario
>  * pick up all the R-B flags from Ray
>  * drop boost/refresh_freq_limits callback
>  * reuse policy->driver_data to store amd_cpudata struct
>  * use switch-case in the driver mode switching function
>  * add Kconfig dependency the INTEL_PSTATE for AMD_PSTATE build
>  * fix some other code format and typos
> 
> changes from v7:
>  * remove  iowait boost functions code
>  * pick up ack by flag from Huang Ray.
>  * add one new patch to support multiple working modes in the amd_pstate_param(),aligned with Wyse 
>  * drop the patch "[v7 08/13] cpufreq: amd-pstate: add frequency dynamic boost sysfs control"
>  * replace the cppc_get_epp_caps() with new cppc_get_epp_perf() wihch is
>    more simple to use
>  * remove I/O wait boost code from amd_pstate_update_status()
>  * replace cppc_active var with enum type AMD_PSTATE_ACTIVE
>  * squash amd_pstate_epp_verify_policy() into sigle function
>  * remove "amd pstate" string from the pr_err, pr_debug logs info
>  * rework patch [v7 03/13], move the common EPP profiles declaration
>    into cpufreq.h which will be used by amd-pstate and intel-pstate
>  * combine amd psate init functions.
>  * remove epp_powersave from amd-pstate.h and dropping the codes.
>  * move amd_pstate_params{} from amd-pstate.h into amd-pstate.c
>  * drive some other feedbacks from huang ray 
> 
> changes from v6:
>  * fix one legacy kernel hang issue when amd-pstate driver unregistering
>  * add new documentation to introduce new global sysfs attributes
>  * use sysfs_emit_at() to print epp profiles array
>  * update commit info for patch v6 patch 1/11 as Mario sugguested.
>  * trying to add the EPP profiles into cpufreq.h, but it will cause lots
>    of build failues,continue to keep cpufreq_common.h used in v7
>  * update commit info using amd-pstate as prefix same as before.
>  * remove CONFIG_ACPI for the header as Ray suggested.
>  * move amd_pstate_kobj to where it is used in patch "add frequency dynamic boost sysfs control"
>  * drive feedback removing X86_FEATURE_CPPC check for the epp init from Huang Ray 
>  * drive feedback from Mario
>  
> change from v5:
>  * add one common header `cpufreq_commoncpufreq_common` to extract EPP profiles 
>    definition for amd and intel pstate driver.
>  * remove the epp_off value to avoid confusion.
>  * convert some other sysfs sprintf() function with sysfs_emit() and add onew new patch
>  * add acpi pm server priofile detection to enable dynamic boost control
>  * fix some code format with checkpatch script
>  * move the EPP profile declaration into common header file `cpufreq_common.h`
>  * fix commit typos
> 
> changes from v4:
>  * rebase driver based on the v6.1-rc7
>  * remove the builtin changes patch because pstate driver has been
>    changed to builtin type by another thread patch
>  * update Documentation: amd-pstate: add amd pstate driver mode introduction 
>  * replace sprintf with sysfs_emit() instead.
>  * fix typo for cppc_set_epp_perf() in cppc_acpi.h header
> 
> changes from v3:
>  * add one more document update patch for the active and passive mode
>    introducion.
>  * drive most of the feedbacks from Mario
>  * drive feedback from Rafael for the cppc_acpi driver.
>  * remove the epp raw data set/get function
>  * set the amd-pstate drive by passing kernel parameter
>  * set amd-pstate driver disabled by default if no kernel parameter
>    input from booting
>  * get cppc_set_auto_epp and cppc_set_epp_perf combined
>  * pick up reviewed by flag from Mario
> 
> changes from v2:
>  * change pstate driver as builtin type from module
>  * drop patch "export cpufreq cpu release and acquire"
>  * squash patch of shared mem into single patch of epp implementation
>  * add one new patch to support frequency boost control
>  * add patch to expose driver working status checking
>  * rebase driver into v6.1-rc4 kernel release
>  * move some declaration to amd-pstate.h
>  * drive feedback from Mario for the online/offline patch
>  * drive feedback from Mario for the suspend/resume patch
>  * drive feedback from Ray for the cppc_acpi and some other patches
>  * drive feedback from Nathan for the epp patch
> 
> changes from v1:
>  * rebased to v6.0
>  * drive feedbacks from Mario for the suspend/resume patch
>  * drive feedbacks from Nathan for the EPP support on msr type
>  * fix some typos and code style indent problems
>  * update commit comments for patch 4/7
>  * change the `epp_enabled` module param name to `epp`
>  * set the default epp mode to be false
>  * add testing for the x86_energy_perf_policy utility patchset(will
>    send that utility patchset with another thread)
> 
> v10:https://lore.kernel.org/lkml/20230106061420.95715-1-perry.yuan@xxxxxxx/
> v9: https://lore.kernel.org/lkml/20221225163442.2205660-1-perry.yuan@xxxxxxx/
> v8: https://lore.kernel.org/lkml/20221219064042.661122-1-perry.yuan@xxxxxxx/
> v7: https://lore.kernel.org/lkml/20221208111852.386731-1-perry.yuan@xxxxxxx/
> v6: https://lore.kernel.org/lkml/20221202074719.623673-1-perry.yuan@xxxxxxx/
> v5: https://lore.kernel.org/lkml/20221128170314.2276636-1-perry.yuan@xxxxxxx/
> v4: https://lore.kernel.org/lkml/20221110175847.3098728-1-Perry.Yuan@xxxxxxx/
> v3: https://lore.kernel.org/all/20221107175705.2207842-1-Perry.Yuan@xxxxxxx/
> v2: https://lore.kernel.org/all/20221010162248.348141-1-Perry.Yuan@xxxxxxx/
> v1: https://lore.kernel.org/all/20221009071033.21170-1-Perry.Yuan@xxxxxxx/
> 
> Perry Yuan (10):
>   ACPI: CPPC: Add AMD pstate energy performance preference cppc control
>   Documentation: amd-pstate: add EPP profiles introduction
>   cpufreq: amd-pstate: implement Pstate EPP support for the AMD
>     processors
>   cpufreq: amd-pstate: implement amd pstate cpu online and offline
>     callback
>   cpufreq: amd-pstate: implement suspend and resume callbacks
>   cpufreq: amd-pstate: add driver working mode switch support
>   Documentation: amd-pstate: add amd pstate driver mode introduction
>   Documentation: introduce amd pstate active mode kernel command line
>     options
>   cpufreq: amd-pstate: convert sprintf with sysfs_emit()
>   Documentation: amd-pstate: introduce new global sysfs attributes
> 
> Wyes Karny (1):
>   cpufreq: amd-pstate: optimize driver working mode selection in
>     amd_pstate_param()
> 

Hi Rafael,

We have finished the review for these series, may we know if any additional
comments from your side?

Thanks,
Ray