Windows® Internals, Sixth Edition, Part 2

Table 8-10. Processor Performance Policies (GUID_PROCESSOR_PERF)

Policy GUID

Policy Meaning

INCREASE/DECREASE_THRESHOLD

Specifies the busy threshold that must be met before changing the processor’s performance state

INCREASE/DECREASE_POLICY

Specifies the algorithm used to select a new performance state when the ideal performance state does not match the current performance state

INCREASE/DECREASE_TIME

Specifies the minimum number of performance check intervals since the last performance state change before the performance state can be changed

TIME_CHECK

Specifies the amount of time that must expire before processor performance states and parked cores may be reevaluated (in milliseconds)

BOOST_POLICY

Specifies how much processors may opportunistically increase frequency above maximum when allowed by current operating conditions

ALLOW_THROTTLING

Allows processors to use throttle states (T states) in addition to performance states.

HISTORY

Specifies the number of processor-performance time-check intervals to use when calculating the average utility

Table 8-11. Idle State Management Policies (GUID_PROCESSOR_IDLE)

Policy GUID

Policy Meaning

ALLOW_SCALING

Specifies whether the idle state promotion and demotion values should be scaled based on the current performance state

DISABLE

Specifies whether idle states should be disabled

TIME_CHECK

Specifies the time that must elapse since the last idle state promotion or demotion before idle states may be promoted or demoted again (in microseconds)

DEMOTE/PROMOTE_THRESHOLD

Specifies the busy threshold that must be met before changing the idle state of the processor

Table 8-12. Core Parking Policies (GUID_PROCESSOR_CORE_PARKING)

Policy GUID

Policy Meaning

INCREASE/DECREASE_THRESHOLD

Specifies the busy threshold that must be met before changing the number of cores that are unparked

INCREASE/DECREASE_POLICY

Specifies the algorithm used to select the number of cores to park or unpark when required

MAX/MIN_CORES

Specifies the number of unparked cores allowed (in a percentage)

INCREASE/DECREASE_TIME

Specifies the minimum number of performance-check intervals that must elapse before more cores can be parked or unparked

CORE_OVERRIDE

Ensures that at least one processor remains unparked per core

PERF_STATE

Specifies what performance state a processor enters when parked

Table 8-13. Affinity History Policies (GUID_PROCESSOR_CORE_PARKING_AFFINITY_HISTORY)

Policy GUID

Policy Meaning

DECREASE_FACTOR

Specifies the factor by which to decrease affinity history on each core after the current performance check

THRESHOLD

Specifies the threshold above which a core is considered to have had significant affinitized work scheduled to it while parked

WEIGHTING

Specifies the weighting given to each occurrence where affinitized work was scheduled to a parked core

Table 8-14. Overutilization Policies (GUID_PROCESSOR_CORE_PARKING_OVER_UTILIZATION)

Policy GUID

Policy Meaning

HISTORY_DECREASE_FACTOR

Specifies the factor by which to decrease the overutilization history on each core after the current performance check

HISTORY_THRESHOLD

Specifies the threshold above which a core is considered to have been recently overutilized while parked

WEIGHTING

Specifies the weighting given to each occurrence when a parked core is found to be overutilized

THRESHOLD

Specifies the busy threshold that must be met before a parked core is considered overutilized

EXPERIMENT: Viewing Current Core Parking Policy