DISK_PERFORMANCE structure (winioctl.h)

Provides disk performance information. It is used by the IOCTL_DISK_PERFORMANCE control code.

Syntax

typedef struct _DISK_PERFORMANCE {
  LARGE_INTEGER BytesRead;
  LARGE_INTEGER BytesWritten;
  LARGE_INTEGER ReadTime;
  LARGE_INTEGER WriteTime;
  LARGE_INTEGER IdleTime;
  DWORD         ReadCount;
  DWORD         WriteCount;
  DWORD         QueueDepth;
  DWORD         SplitCount;
  LARGE_INTEGER QueryTime;
  DWORD         StorageDeviceNumber;
  WCHAR         StorageManagerName[8];
} DISK_PERFORMANCE, *PDISK_PERFORMANCE;

Members

BytesRead

The number of bytes read.

BytesWritten

The number of bytes written.

ReadTime

The time it takes to complete a read.

WriteTime

The time it takes to complete a write.

IdleTime

The idle time.

ReadCount

The number of read operations.

WriteCount

The number of write operations.

QueueDepth

The depth of the queue.

SplitCount

The cumulative count of I/Os that are associated I/Os.

An associated I/O is a fragmented I/O, where multiple I/Os to a disk are required to fulfill the original logical I/O request. The most common example of this scenario is a file that is fragmented on a disk. The multiple I/Os are counted as split I/O counts.

QueryTime

The system time stamp when a query for this structure is returned.

Use this member to synchronize between the file system driver and a caller.

StorageDeviceNumber

The unique number for a device that identifies it to the storage manager that is indicated in the StorageManagerName member.

StorageManagerName[8]

The name of the storage manager that controls this device.

Examples of storage managers are "PhysDisk," "FTDISK," and "DMIO".

Requirements

Requirement	Value
Minimum supported client	Windows XP [desktop apps only]
Minimum supported server	Windows Server 2003 [desktop apps only]
Header	winioctl.h (include Windows.h)

See also

IOCTL_DISK_PERFORMANCE