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

The name of the storage manager that controls this device.

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

Requirements

See Also

IOCTL_DISK_PERFORMANCE

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Build date: 10/2/2008