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PEP_PPM_FEEDBACK_READ structure (pep_x.h)

  • Article

The PEP_PPM_FEEDBACK_READ structure contains the value read from a processor performance feedback counter.

Syntax

typedef struct _PEP_PPM_FEEDBACK_READ {
  ULONG CounterIndex;
  union {
    ULONG64 InstantaneousValue;
    struct {
      ULONG64 NominalCount;
      ULONG64 ActualCount;
    };
  };
} PEP_PPM_FEEDBACK_READ, *PPEP_PPM_FEEDBACK_READ;

Members

CounterIndex

The index that identifies which processor performance feedback counter to read. If the platform extension plug-in (PEP) supports N counters for this processor, counter indexes range from 0 to N-1. The PEP previously supplied the number of supported counters in response to a PEP_NOTIFY_PPM_QUERY_CAPABILITIES notification.

InstantaneousValue

The current instantaneous value read from the counter, if the counter generates an instantaneous value.

NominalCount

The nominal accumulated value of the counter. The accumulated value is the sum of all actual values that have so far been read from the counter hardware.

ActualCount

The actual value read from the counter.

Remarks

The unnamed union contains either an instantaneous counter value, if the counter generates an instantaneous value, or both relative and accumulated counter values, if the counter hardware generates a relative value.

This structure is used by the PEP_NOTIFY_PPM_FEEDBACK_READ notification. The CounterIndex member of the structure contains an input value supplied by the Windows power management framework (PoFx) when this notification is set. The other members contain output values that the PEP writes to the structure in response to the notification. The PEP writes to the InstantaneousValue member if the counter generates an instantaneous value, or to the NominalCount and ActualCount members if the counter generates a relative value.

Both an instantaneous counter and a relative counter are reset to zero when power is first turned on, but reading a relative counter causes the count to reset to zero, whereas reading an instantaneous counter does not reset the count. The PEP previously indicated whether the counter is instantaneous or relative in response to a PEP_NOTIFY_PPM_QUERY_FEEDBACK_COUNTERS notification.

Requirements

Requirement Value
Minimum supported client Supported starting with Windows 10.
Header pep_x.h (include Pep_x.h)

See also