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PEP_PROCESSOR_IDLE_STATE structure (pep_x.h)

  • Article

The PEP_PROCESSOR_IDLE_STATE structure describes the capabilities of a processor idle state.

Syntax

typedef struct _PEP_PROCESSOR_IDLE_STATE {
  union {
    ULONG Ulong;
    struct {
      ULONG Interruptible : 1;
      ULONG CacheCoherent : 1;
      ULONG ThreadContextRetained : 1;
      ULONG CStateType : 4;
      ULONG Reserved : 25;
    };
  };
} PEP_PROCESSOR_IDLE_STATE, *PPEP_PROCESSOR_IDLE_STATE;

Members

Ulong

Flag bits and status fields accessed as a single 32-bit unsigned integer value.

Interruptible

Whether the processor can respond to interrupts when in this idle state. Set this flag bit to 1 if the processor can respond to interrupts, and to 0 if it cannot.

CacheCoherent

Whether the processor's local cache or caches remain coherent through the duration of this processor idle state. Set this flag bit to 1 if cache coherency is maintained in this idle state, and to 0 if it is not.

ThreadContextRetained

Whether thread context is retained in this processor idle state. Set this flag bit to 1 if the processor hardware retains the thread context across the idle transition. Set to 0 if the processor uses the multiprocessor parking protocol to exit the idle state and return control to the operating system. For more information about this protocol, see the document titled Multiprocessor Startup for ARM Platforms at the ACPI Component Architecture site.

CStateType

The C-state type of the processor idle state. Set this bit field to zero if this idle state does not correspond to an ACPI-defined C-state. Otherwise, set this bit field to the C-state number. That is, set CStateType = 1 for C1, set CStateType = 2 for C2, and so on. For more information about C-states, see section 8.1, Processor Power States, of the ACPI 5.0 specification.

Reserved

Reserved for future use.

Remarks

The unnamed union contains a collection of flag bits and status fields that can be accessed either individually as bit fields, or together as a 32-bit unsigned integer value.

The unnamed struct contains flag bits and status fields accessed as individual bit fields.

The IdleStates member of the PEP_PPM_QUERY_IDLE_STATES structure is the first element in an array of PEP_PROCESSOR_IDLE_STATE structures.

Requirements

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

See also