Windows supports multiple Power Profiles which you can employ to tune your machine towards performance or energy consumption. ETWAnalyzer can display the currently active power plan settings with
ETWAnalyzer -dump Power -fd xx.json
Below are all CPU settings for the Balanced Power Plan printed:
ETWAnalyzer -dump power -fd c:\temp\Extract\power_Balanced.json
File Date : 1/30/2024 10:44:46 PM
File Name : Balanced_Win11
CPU Power Configuration
ActiveProfile : Balanced
Base Profile : Balanced
Autonomous Mode : True
HeteroPolicyInEffect : 0
HeteroPolicyThreadScheduling : Automatic
HeteroPolicyThreadSchedulingShort : Automatic
DecreaseLevelThreshold Class 1 : 25,25,25,25
DecreaseLevelThreshold Class 2 : 50,50,50,50
ShortVsLongThreadThreshold us : 0
LongRunningThreadsLowerArchitectureLimit: 0
EnergyPreference % : 50
EnergyPreference % Class 1 : 50
BoostMode : Aggressive
BoostPolicy % : 60
DecreasePolicy : Ideal
DecreaseStabilizationInterval : 1 ms
DecreaseThreshold % : 20
IncreasePolicy : Ideal
IncreasePolicy Class 1 : 3
IncreaseStabilizationInterval : 1 ms
IncreaseThreshold % : 60
IncreaseStabilizationIntervalClass1 : 1
StabilizationInterval : 30 ms
IncreaseThresholdPercentClass1 : 60,60,60,60
IncreaseThresholdPercentClass2 : 90,90,90,90
LatencySensitivity % : 99
MaxFrequency MHz Class 0 : 0
MaxFrequency MHz Class1 : 0
MaxThrottleFrequency % : 100
MaxThrottleFrequency % Class 1 : 100
MinThrottleFrequency % : 5
MinThrottleFrequency Class 1 % : 5
SystemCoolingPolicy : Active
ThrottlePolicy : Automatic
TimeWindowSize : 1
Idle Configuration
DeepestIdleState : 0
DemoteThreshold : 40
Enabled : True
MinimumDurationBetweenChecks : 50 ms
PromoteThreshold % : 60
ScalingEnabled : False
Core Parking
ConcurrencyHeadroomThreshold % : 50
ConcurrencyThreshold % : 95
MaxEfficiencyClass1UnparkedProcessor % : 100
MaxUnparkedProcessor % : 100
MinParkedDuration : 1 ms
MinUnparkedDuration : 3 ms
MinUnparkedProcessor % : 4
MinEfficiencyClass1UnparkedProcessor % : 0
OverUtilizationThreshold % : 85
ParkingPerformanceState : NoPreference
InitialPerformanceClass1 % : 100
SoftParkLatencyUs : 10 us
ParkingPolicy : Ideal
UnparkingPolicy : Ideal
UtilityDistributionEnabled : False
UtilityDistributionThreshold % : 90
ETWAnalyzer currently cares only about CPU settings to track down performance regression issues. It does not show Monitor, Hard Disk and related settings. The data is there and can be viewed in WPA if you go to Trace - System Configuration - Power Settings
This are quite a few settings (37) but still only a fraction of all possible CPU Power settings (75) present on a current Windows 11 system (12/2023). TraceProcesssing does currently not parse all of them but we hope that will be fixed in a future version. The settings are part of three groups
- CPU Power Configuration
- Idle Configuration
- Core Parking
Some settings can be considered legacy if the CPU is in autonomous mode where the settings from Windows Processor Power Management are not considered and the CPU tunes itself without much help of the OS. Unfortunately it is not clearly documented which settings are relevant when the CPU (all modern CPUs since Skylake support Speed Shift) is tuning itself in autonomous mode.
Windows comes with 3 built in power profiles
- Power Saver
- Balanced
- High Performance
To see the currently active power profile you can record with wpr (part of Windows) the power settings
wpr -start Power
wpr -stop c:\temp\Power_1.json
If you switch between the three built in power profiles you will get after extraction 3 json files which you can easily query to find where the differences in tuning are.
ETWAnlayzer supports the -Diff flag for -Dump Power to show only the parameters which are different between the three power profiles:
ETWAnalyzer -dump Power -Diff -fd c:\temp\Extract\power_Balanced.json -fd c:\temp\Extract\power_HighPerformance.json -fd c:\temp\Extract\power_PowerSaver.json
Skipped 0 entries with identical power configurations.
File Date : 1/30/2024 10:44:46 PM 1/30/2024 10:45:05 PM 1/30/2024 10:45:46 PM
File Name : Balanced_Win11 HighPerformance_Win11 PowerSaver_Win11
CPU Power Configuration
ActiveProfile : Balanced HighPerformance PowerSaver
Base Profile : Balanced HighPerformance PowerSaver
Autonomous Mode : True ... False
HeteroPolicyInEffect : 0 ... 4
DecreaseLevelThreshold Class 1 : 25,25,25,25 ... 50,50,50,50
EnergyPreference % : 50 0 60
EnergyPreference % Class 1 : 50 0 60
BoostPolicy % : 60 100 0
DecreasePolicy : Ideal Single Rocket
DecreaseThreshold % : 20 10 60
IncreasePolicy : Ideal Rocket Single
IncreaseStabilizationInterval : 1 ms ... 3 ms
IncreaseThreshold % : 60 30 90
IncreaseStabilizationIntervalClass1 : 1 ... 3
StabilizationInterval : 30 ms 15 ms 200 ms
IncreaseThresholdPercentClass1 : 60,60,60,60 ... 90,90,90,90
LatencySensitivity % : 99 ... 0
MaxThrottleFrequency % Class 1 : 100 ... 75
MinThrottleFrequency % : 5 100 5
MinThrottleFrequency Class 1 % : 5 100 5
SystemCoolingPolicy : Active ... Passive
Idle Configuration
DemoteThreshold : 40 ... 20
PromoteThreshold % : 60 ... 40
ScalingEnabled : False ... True
Core Parking
ConcurrencyHeadroomThreshold % : 50 ... 20
ConcurrencyThreshold % : 95 ... 97
MinUnparkedDuration : 3 ms ... 2 ms
MinUnparkedProcessor % : 4 ... 100
OverUtilizationThreshold % : 85 60 90
InitialPerformanceClass1 % : 100 ... 50
SoftParkLatencyUs : 10 us 1000 us 0 us
You can add -Details to get help for each of the settings to give you an idea what the setting is all about and how you can
relate that with powercfg commands for further experimentation.
To e.g. set the HeteroPolicyInEffect property value for the current power profile and to make it active you can use powercfg:
powercfg /SETACVALUEINDEX SCHEME_CURRENT SUB_PROCESSOR HETEROPOLICY 3
powercfg /SETACTIVE SCHEME_CURRENT
The detailed output includes the setting GUID and the locale independent shortcut name of powercfg. Most settings are hidden in the UI. To make a hidden setting visible you can use powercfg with the setting GUID/Name and unhide it:
powercfg /attributes SUB_PROCESSOR HETEROPOLICY -ATTRIB_HIDE
Below is some example output when you have enabled detailed output.
ETWAnalyzer -dump Power -Details -fd c:\temp\Extract\power_Balanced.json
...
HETEROPOLICY 7f2f5cfa-f10c-4823-b5e1-e93ae85f46b5
Heterogeneous policy in effect
Specify what policy to be used on systems with at least two different Processor Power Efficiency Classes.
Subgroup:
Processor power management
Possible values (index - hexadecimal or string value - friendly name - descr):
0 - 00000000 - Use heterogeneous policy 0 - Heterogeneous policy 0.
1 - 00000001 - Use heterogeneous policy 1 - Heterogeneous policy 1.
2 - 00000002 - Use heterogeneous policy 2 - Heterogeneous policy 2.
3 - 00000003 - Use heterogeneous policy 3 - Heterogeneous policy 3.
4 - 00000004 - Use heterogeneous policy 4 - Heterogeneous policy 4.
HeteroPolicyInEffect : 4
SCHEDPOLICY 93b8b6dc-0698-4d1c-9ee4-0644e900c85d
Heterogeneous thread scheduling policy
Specify what thread scheduling policy to use on heterogeneous systems.
Subgroup:
Processor power management
Possible values (index - hexadecimal or string value - friendly name - descr):
0 - 00000000 - All processors - Schedule to any available processor.
1 - 00000001 - Performant processors - Schedule exclusively to more performant processors.
2 - 00000002 - Prefer performant processors - Schedule to more performant processors when possible.
3 - 00000003 - Efficient processors - Schedule exclusively to more efficient processors.
4 - 00000004 - Prefer efficient processors - Schedule to more efficient processors when possible.
5 - 00000005 - Automatic - Let the system choose an appropriate policy.
HeteroPolicyThreadScheduling : Automatic
...
With modern CPUs a lot of switches have been added which makes performance tuning challenging. TraceProcessing does currently not surface the following CPU Power settings.
- A floor performance for Processor Power Efficiency Class 0 when there are Processor Power Efficiency Class 1 processors unparked
- Complex unpark policy
- Latency sensitivity hint min unparked cores/packages
- Latency sensitivity hint min unparked cores/packages for Processor Power Efficiency Class 1
- Latency sensitivity hint processor performance for Processor Power Efficiency Class 1
- Long running threads' processor architecture upper limit
- Module unpark policy
- Processor autonomous activity window
- Processor Duty Cycling
- Processor performance core parking parked performance state for Processor Power Efficiency Class 1
- Processor performance decrease policy for Processor Power Efficiency Class 1
- Processor performance decrease threshold for Processor Power Efficiency Class 1
- Processor performance decrease time for Processor Power Efficiency Class 1
- Processor performance decrease time for Processor Power Efficiency Class 1
- Processor performance history count for Processor Power Efficiency Class 1
- Processor performance increase threshold for Processor Power Efficiency Class 1
- Short running threads' processor architecture lower limit
- Short running threads' processor architecture upper limit
- Smt threads unpark policy
The following settings are parsed by ETWAnalyzer on its own because they are important and not surfaced by TraceProcessing
- Processor performance autonomous mode
- Heterogeneous thread scheduling policy
- Heterogeneous short running thread scheduling policy
- Heterogeneous policy in effect
- Active Profile Guid
- Base Profile Guid
- Initial performance for Processor Power Efficiency Class 1 when unparked
- Long running threads' processor architecture lower limit
- Minimum processor state for Processor Power Efficiency Class 1
- Processor energy performance preference policy
- Processor energy performance preference policy for Processor Power Efficiency Class 1
- Short vs. long running thread threshold
- Processor performance level decrease threshold for Processor Power Efficiency Class 1 processor count decrease
- Processor performance level decrease threshold for Processor Power Efficiency Class 2 processor count decrease
- Processor performance increase policy for Processor Power Efficiency Class 1
- Processor performance level increase threshold for Processor Power Efficiency Class 1 processor count increase
- Processor performance level increase threshold for Processor Power Efficiency Class 2 processor count increase
- Maximum processor state for Processor Power Efficiency Class 1
- Processor performance core parking soft park latency
- Processor performance increase time for Processor Power Efficiency Class 1
This list was extracted from a Windows 11 machine. The vigilant reader may have spotted Efficiency Class 2 settings which indicate that there can exist not only one E-Core type inside one CPU. With the release of Intel Meteor lake CPUs we have P/E and Lower Energy E Cores. It is still unclear if these have a different performance rating. In theory Lower Energy E cores should show up as cores with an Efficiency Level 0, then followed by the traditional E Cores with Level 1 and finally the P-Cores with Level 2.
If you intend to test different power profiles the best tip for beginners is to know that you do NOT need to reboot when you switch to a different profile. The settings take immediate effect.
Most relevant settings are hidden and not accessible from the UI. There are other tools out there like PowerSettingsExplorer which makes comparing and testing Power Profile settings much easier to work with.
To get Power settings data with xperf you need to execute a Capture State command for the Microsoft-Windows-Kernel-Power ETW provider to dump power settings to ETW. This are just a few events and consume ca. 150 KB of data which is nothing.
xperf -capturestate <YouUserModeSessionName> Microsoft-Windows-Kernel-Power
You get then all power setting entries which are identified by a SettingGuid and its configured value as binary data.
| Event Name | Id | SettingGuid (Field 1) | DataSize (Field 2) | Data (Field 3) | Override (Field 4) |
|---|---|---|---|---|---|
| Microsoft-Windows-Kernel-Power/PowerSettingRundown/win:Info | 111 | 4d2b0152-7d5c-498b-88e2-34345392a2c5 | 0x00000004 | 00000004 0f 00 00 00 | False |
| Microsoft-Windows-Kernel-Power/PowerSettingRundown/win:Info | 111 | 4e4450b3-6179-4e91-b8f1-5bb9938f81a1 | 0x00000004 | 00000004 00 00 00 00 | False |
The SettingGuid is related to the Guids used by powercfg. We can query a specific power profile and then search for that Guid to get an idea what the power profile setting is about:
powercfg /q a1841308-3541-4fab-bc81-f71556f20b4a | findstr /i 4d2b0152
Power Setting GUID: 4d2b0152-7d5c-498b-88e2-34345392a2c5 (Processor performance time check interval)
The same data is also part of the provider Microsoft-Windows-UserModePowerService which contains the group GUID to which
subgroup this setting belongs to if you want to get an overview how many power settings exist.
Windows groups cores into efficiency classes which is a byte value. If you have P/E cores then the E cores are 0 and the P Cores are 1. This scheme is extensible, but if you get in future e.g. two E-Core types then the P-Cores will get Efficiency Class 2 which is a strange way to number things.
Below is the official Documentation from TraceProcessing Library:
Processor power efficiency class describes the relative power efficiency of the associated processor. Lower efficiency class numbers are more efficient than higher ones (e.g. efficiency class 0 should be treated as more efficient than efficiency class 1). However, absolute values of this number have no meaning: 2 isn't necessarily half as efficient as 1.
The easiest way is to download ETWController, select the Default profile, press Start and wait until the state turns green. Then press stop and extract the ETL file/s with ETWAnalyzer. All profiles from Multiprofile.wprp record the currently selected power profile data. From the built-in wpr profiles only the Power profile will activate the right providers, which will also enable Frequency data recording.
C>EtwAnalyzer -extract all -fd C:\PowerProfiles
3 - files found to extract.
Success Extraction of C:\PowerProfiles\Extract\Power_Balanced_Win11_2024-01-30_224446_MAGNON.json
Extracted 1/3 - Failed 0 files.
Success Extraction of C:\PowerProfiles\Extract\Power_HighPerformance_Win11_2024-01-30_224505_MAGNON.json
Extracted 2/3 - Failed 0 files.
Success Extraction of C:\PowerProfiles\Extract\Power_PowerSaver_Win11_2024-01-30_224546_MAGNON.json
Extracted 3/3 - Failed 0 files.
Extracted: 3 files in 00 00:00:04, Failed Files 0
