Low Priority I/O Count Information – SystemLowPriorityInformation

Posted by Matthieu Suiche on Wednesday, April 1, 2009 · Leave a Comment 

Based on Windows Vista I/O priorities manager, Windows 7 provides a new class to retrieve information/statistics about about Low I/O priority counts.

Function: NtQuerySystemInformation
Class: SystemLowPriorityInformation
Privilege: None
Output size: 0×24 bytes

The output structure is the following.

typedef struct _LOW_PRIORITY_INFORMATION
{
ULONG IoLowPriorityReadOperationCount;
ULONG IoLowPriorityWriteOperationCount;
ULONG IoKernelIssuedIoBoostedCount;
ULONG IoPagingReadLowPriorityCount;
ULONG IoPagingReadLowPriorityBumpedCount;
ULONG IoPagingWriteLowPriorityCount;
ULONG IoPagingWriteLowPriorityBumpedCount;
ULONG IoBoostedThreadedIrpCount;
ULONG IoBoostedPagingIrpCount;
ULONG IoBlanketBoostCount; // Added in RC1 (build 7100)
} LOW_PRIORITY_INFORMATION, *PLOW_PRIORITY_INFORMATION;

systemlowiopriorityinfo

Source + Executable are available here.

Edit: LOW_PRIORITY_INFORMATION structure updated in build 7100.

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