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PROCESSOR_NUMBER structure (miniport.h)

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The PROCESSOR_NUMBER structure identifies a processor by its group number and group-relative processor number.

Syntax

typedef struct _PROCESSOR_NUMBER {
  USHORT Group;
  UCHAR  Number;
  UCHAR  Reserved;
} PROCESSOR_NUMBER, *PPROCESSOR_NUMBER;

Members

Group

The group number. If multiprocessor system contains n groups, the groups are numbered from 0 to n-1.

Number

The group-relative processor number. If a group contains m logical processors, the processors are numbered from 0 to m-1.

Reserved

Reserved for future use. Initialize to zero.

Remarks

Windows 7 is the first version of Windows to support processor groups. In Windows 7, only 64-bit versions of Windows support multiple groups; 32-bit versions of Windows support only one group. If a multiprocessor system is running a 64-bit version of Windows and contains no more than 64 logical processors, Windows assigns all processors to group 0. A multiprocessor system that is running a 32-bit version of Windows can contain no more than 32 processors.

In Windows 7, the maximum number of groups in a multiprocessor system is four, but this value might change in future versions of Windows. The safest way to determine the maximum number of groups in Windows 7 or a later version of Windows is to call the KeQueryMaximumGroupCount routine. Kernel-mode drivers that call KeQueryMaximumGroupCount will not require code changes if the formula that is used to calculate the maximum number of groups changes in a future version of Windows.

Kernel-mode routines that use the PROCESSOR_NUMBER structure include KeGetCurrentProcessorNumberEx, KeGetProcessorIndexFromNumber, KeGetProcessorNumberFromIndex, and KeQueryLogicalProcessorRelationship.

Requirements

Requirement Value
Minimum supported client Supported in Windows 7 and later versions of the Windows operating system.
Header miniport.h (include Windows.h, Ntdef.h, Wdm.h, Ntddk.h, Winnt.h, Minitape.h)

See also

KeGetCurrentProcessorNumberEx

KeGetProcessorIndexFromNumber

KeGetProcessorNumberFromIndex

KeQueryLogicalProcessorRelationship

KeQueryMaximumGroupCount