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Win32_PerfRawData_PerfOS_Cache class

The Win32_PerfRawData_PerfOS_Cache raw performance data class provides raw data from performance counters that monitor the file system cache. This cache is an area of physical memory that stores recently used data as long as possible to permit access to the data without having to read from the disk. Because applications typically use the cache, the cache is monitored as an indicator of application I/O operations. When memory is plentiful, the cache can grow; but when memory is scarce, the cache can become too small to be effective.

This class represents the Cache object in System Monitor. The original data source is the PerfOS performance library. The corresponding formatted data class is Win32_PerfFormattedData_PerfOS_Cache. Data is dynamically provided for this class from the performance library object by the WmiPerfInst provider.

Windows Server 2003 and Windows XP:  WMI data for this class is supplied by the Performance Counter Provider.

The following syntax is simplified from MOF code and shows all inherited properties, including the Frequency and Timestamp properties required for class display in System Monitor. For more information about required property qualifiers, see Property Qualifiers for Performance Counter Classes. For more information about CounterType values, see WMI Performance Counter Types.

Syntax

class Win32_PerfRawData_PerfOS_Cache : Win32_PerfRawData
{
  uint32 AsyncCopyReadsPerSec;
  uint32 AsyncDataMapsPerSec;
  uint32 AsyncFastReadsPerSec;
  uint32 AsyncMDLReadsPerSec;
  uint32 AsyncPinReadsPerSec;
  string Caption;
  uint32 CopyReadHitsPercent;
  uint32 CopyReadHitsPercent_Base;
  uint32 CopyReadsPerSec;
  uint32 DataFlushesPerSec;
  uint32 DataFlushPagesPerSec;
  uint32 DataMapHitsPercent;
  uint32 DataMapHitsPercent_Base;
  uint32 DataMapPinsPerSec;
  uint32 DataMapPinsPerSec_Base;
  uint32 DataMapsPerSec;
  string Description;
  uint32 FastReadNotPossiblesPerSec;
  uint32 FastReadResourceMissesPerSec;
  uint32 FastReadsPerSec;
  uint64 Frequency_Object;
  uint64 Frequency_PerfTime;
  uint64 Frequency_Sys100NS;
  uint32 LazyWriteFlushesPerSec;
  uint32 LazyWritePagesPerSec;
  uint32 MDLReadHitsPercent;
  uint32 MDLReadHitsPercent_Base;
  uint32 MDLReadsPerSec;
  string Name;
  uint32 PinReadHitsPercent;
  uint32 PinReadHitsPercent_Base;
  uint32 PinReadsPerSec;
  uint32 ReadAheadsPerSec;
  uint32 SyncCopyReadsPerSec;
  uint32 SyncDataMapsPerSec;
  uint32 SyncFastReadsPerSec;
  uint32 SyncMDLReadsPerSec;
  uint32 SyncPinReadsPerSec;
  uint64 Timestamp_Object;
  uint64 Timestamp_PerfTime;
  uint64 Timestamp_Sys100NS;
};

Members

The Win32_PerfRawData_PerfOS_Cache class has these types of members:

Properties

The Win32_PerfRawData_PerfOS_Cache class has these properties.

AsyncCopyReadsPerSec
Data type: uint32
Access type: Read-only
Qualifiers: DisplayName ("Async Copy Reads/sec") , CounterType (272696320) , DefaultScale (0) , PerfDetail (400)

Frequency of read requests from pages of the file system cache that require a memory copy of the data from the cache to the application buffer. The application regains control immediately even if the disk must be accessed to retrieve the page.

AsyncDataMapsPerSec
Data type: uint32
Access type: Read-only
Qualifiers: DisplayName ("Async Data Maps/sec") , CounterType (272696320) , DefaultScale (0) , PerfDetail (400)

Frequency that an application, using a file system such as NTFS to map a file page into the file system cache for reading, does not wait for the page to be retrieved if it is not in main memory.

AsyncFastReadsPerSec
Data type: uint32
Access type: Read-only
Qualifiers: DisplayName ("Async Fast Reads/sec") , CounterType (272696320) , DefaultScale (-1) , PerfDetail (400)

Frequency of read requests from the file system cache that bypass the installed file system and retrieve the data directly from the cache. Normally, file I/O requests invoke the appropriate file system to retrieve data from a file, but this path permits data to be retrieved from the cache directly (without file system involvement) if the data is in the cache. If the data is not in the cache, the request (application program call) does not wait until the data has been retrieved from disk, but gets control immediately.

AsyncMDLReadsPerSec
Data type: uint32
Access type: Read-only
Qualifiers: DisplayName ("Async MDL Reads/sec") , CounterType (272696320) , DefaultScale (0) , PerfDetail (400)

Frequency of read operations from the file system cache that use a Memory Descriptor List (MDL) to access the pages. The MDL contains the physical address of each page in the transfer, thus permitting Direct Memory Access (DMA) of the pages. If the accessed page(s) are not in main memory, the calling application program does not wait for the pages to be read in from a disk by a page fault.

AsyncPinReadsPerSec
Data type: uint32
Access type: Read-only
Qualifiers: DisplayName ("Async Pin Reads/sec") , CounterType (272696320) , DefaultScale (0) , PerfDetail (400)

Frequency of reading data into the file system cache preparatory to writing the data back to disk. Pages read in this fashion are pinned in memory at the completion of the read. The file system regains control immediately even if the disk must be accessed to retrieve the page. While pinned, a page's physical address is not altered.

Caption
Data type: string
Access type: Read-only

Short textual description for the statistic or metric. This property is inherited from CIM_StatisticalInformation.

CopyReadHitsPercent
Data type: uint32
Access type: Read-only
Qualifiers: DisplayName ("Copy Read Hits %") , CounterType (549585920) , DefaultScale (0) , PerfDetail (300)

Percentage of cache copy read requests that hit the cache, that is, they did not require a disk read to provide access to the page in the cache. A copy read is a file read operation that is satisfied by a memory copy from a page in the cache to the application buffer. The LAN Redirector uses this method for retrieving information from the cache, as does the LAN Server for small transfers. This is a method used by the disk file systems as well.

CopyReadHitsPercent_Base
Data type: uint32
Access type: Read-only
Qualifiers: DisplayName (" ") , CounterType (1073939457) , DefaultScale (0) , PerfDetail (300)

Base value for CopyReadHitsPercent used to calculate percentage.

CopyReadsPerSec
Data type: uint32
Access type: Read-only
Qualifiers: DisplayName ("Copy Reads/sec") , CounterType (272696320) , DefaultScale (0) , PerfDetail (300)

Frequency of read operations from pages of the file system cache that involve a memory copy of the cache data to the application buffer. The LAN Redirector uses this method for retrieving information from the file system cache, as does the LAN Server for small transfers. This is a method used by the disk file systems as well.

DataFlushesPerSec
Data type: uint32
Access type: Read-only
Qualifiers: DisplayName ("Data Flushes/sec") , CounterType (272696320) , DefaultScale (0) , PerfDetail (400)

Rate at which the file system cache has flushed its contents to disk as the result of a request to flush or to satisfy a write-through file write request. More than one page can be transferred on each flush operation.

DataFlushPagesPerSec
Data type: uint32
Access type: Read-only
Qualifiers: DisplayName ("Data Flush Pages/sec") , CounterType (272696320) , DefaultScale (0) , PerfDetail (200)

Number of pages the file system cache has flushed to disk as a result of a request to flush or to satisfy a write-through file write request. More than one page can be transferred on each flush operation.

DataMapHitsPercent
Data type: uint32
Access type: Read-only
Qualifiers: PerfDefault, DisplayName ("Data Map Hits %") , CounterType (549585920) , DefaultScale (0) , PerfDetail (400)

Percentage of data maps in the file system cache that could be resolved without having to retrieve a page from the disk, because the page was already in physical memory.

DataMapHitsPercent_Base
Data type: uint32
Access type: Read-only
Qualifiers: DisplayName (" ") , CounterType (1073939457) , DefaultScale (0) , PerfDetail (400)

Base value for DataMapsHitsPercent used to calculate percentage.

DataMapPinsPerSec
Data type: uint32
Access type: Read-only
Qualifiers: DisplayName ("Data Map Pins/sec") , CounterType (549585920) , DefaultScale (0) , PerfDetail (400)

Frequency of data maps in the file system cache that resulted in pinning a page in main memory, an action usually preparatory to writing to the file on disk. While pinned, a page's physical address in main memory and virtual address in the file system cache is not altered.

DataMapPinsPerSec_Base
Data type: uint32
Access type: Read-only
Qualifiers: DisplayName (" ") , CounterType (1073939457) , DefaultScale (0) , PerfDetail (400)

Base value for DataMapPinsPerSec.

DataMapsPerSec
Data type: uint32
Access type: Read-only
Qualifiers: DisplayName ("Data Maps/sec") , CounterType (272696320) , DefaultScale (0) , PerfDetail (300)

Frequency that a file system such as NTFS, maps a page of a file into the file system cache to read the page.

Description
Data type: string
Access type: Read-only

Textual description of the statistic or metric. This property is inherited from CIM_StatisticalInformation.

FastReadNotPossiblesPerSec
Data type: uint32
Access type: Read-only
Qualifiers: DisplayName ("Fast Read Not Possibles/sec") , CounterType (272696320) , DefaultScale (0) , PerfDetail (400)

Frequency of attempts by an Application Program Interface (function) function call to bypass the file system to get to data in the file system cache that could not be honored without invoking the file system.

FastReadResourceMissesPerSec
Data type: uint32
Access type: Read-only
Qualifiers: DisplayName ("Fast Read Resource Misses/sec") , CounterType (272696320) , DefaultScale (0) , PerfDetail (400)

Frequency of cache misses caused by the lack of available resources to satisfy the request.

FastReadsPerSec
Data type: uint32
Access type: Read-only
Qualifiers: DisplayName ("Fast Reads/sec") , CounterType (272696320) , DefaultScale (-1) , PerfDetail (300)

Frequency of read requests from the file system cache that bypass the installed file system and retrieve the data directly from the cache. Normally, file I/O requests invoke the appropriate file system to retrieve data from a file, but this path permits direct retrieval of data from the cache without file system involvement if the data is in the cache. Even if the data is not in the cache, one invocation of the file system is avoided.

Frequency_Object
Data type: uint64
Access type: Read-only

Frequency, in ticks per second, of Timestamp_Object. This property is defined by the provider. This property is inherited from Win32_Perf.

For more information about using uint64 values in scripts, see Scripting in WMI.

Frequency_PerfTime
Data type: uint64
Access type: Read-only

Frequency, in ticks per second, of Timestamp_Perftime. A value can be obtained by calling the Windows function QueryPerformanceCounter. This property is inherited from Win32_Perf.

For more information about using uint64 values in scripts, see Scripting in WMI.

Frequency_Sys100NS
Data type: uint64
Access type: Read-only

Frequency, in ticks per second, of Timestamp_Sys100NS (10000000). This property is inherited from Win32_Perf.

For more information about using uint64 values in scripts, see Scripting in WMI.

LazyWriteFlushesPerSec
Data type: uint32
Access type: Read-only
Qualifiers: DisplayName ("Lazy Write Flushes/sec") , CounterType (272696320) , DefaultScale (0) , PerfDetail (400)

Rate at which the Lazy Writer thread has written to disk. Lazy Writing is the process of updating the disk after the page has been changed in memory, so that the application that changed the file does not have to wait for the disk write to be complete before proceeding. More than one page can be transferred by each write operation.

LazyWritePagesPerSec
Data type: uint32
Access type: Read-only
Qualifiers: DisplayName (" ") , CounterType (65536) , DefaultScale (0) , PerfDetail (100)

Rate at which the Lazy Writer thread has written to disk. Lazy Writing is the process of updating the disk after the page has been changed in memory, so that the application that changed the file does not have to wait for the disk write to be complete before proceeding. More than one page can be transferred on a single disk write operation.

MDLReadHitsPercent
Data type: uint32
Access type: Read-only
Qualifiers: DisplayName ("MDL Read Hits %") , CounterType (549585920) , DefaultScale (0) , PerfDetail (300)

Percentage of Memory Descriptor List (MDL) Read requests to the file system cache that hit the cache, that is, did not require disk accesses to provide memory access to the page(s) in the cache.

MDLReadHitsPercent_Base
Data type: uint32
Access type: Read-only
Qualifiers: DisplayName (" ") , CounterType (1073939457) , DefaultScale (0) , PerfDetail (300)

Base value for MDLReadHitsPercent used to calculate percentage.

MDLReadsPerSec
Data type: uint32
Access type: Read-only
Qualifiers: DisplayName ("MDL Reads/sec") , CounterType (272696320) , DefaultScale (0) , PerfDetail (300)

Frequency of read operations from the file system cache that use a Memory Descriptor List (MDL) to access the pages. The MDL contains the physical address of each page in the transfer, thus permitting Direct Memory Access (DMA) of the pages. If the accessed page(s) are not in main memory, the calling application program does not wait for the pages to fault in from disk.

Name
Data type: string
Access type: Read-only
Qualifiers: Key, MaxLen (256)

Label by which the statistic or metric is known. When sub-classed, the property can be overridden to be a key property. This property is inherited from CIM_StatisticalInformation.

PinReadHitsPercent
Data type: uint32
Access type: Read-only
Qualifiers: DisplayName ("Pin Read Hits %") , CounterType (549585920) , DefaultScale (0) , PerfDetail (300)

Percentage of pin read requests that hit the file system cache; that is, those that did not require a disk read to provide access to the page in the file system cache. While pinned, a page's physical address in the file system cache is not altered. The LAN Redirector uses this method for retrieving data from the cache, as does the LAN Server for small transfers. This is usually the method used by the disk file systems as well.

PinReadHitsPercent_Base
Data type: uint32
Access type: Read-only
Qualifiers: DisplayName (" ") , CounterType (1073939457) , DefaultScale (0) , PerfDetail (300)

Base value for PinReadHitsPercent used to calculate percentage.

PinReadsPerSec
Data type: uint32
Access type: Read-only
Qualifiers: DisplayName ("Pin Reads/sec") , CounterType (272696320) , DefaultScale (0) , PerfDetail (300)

Frequency of reading data into the file system cache preparatory to writing the data back to disk. Pages read in this fashion are pinned in memory at the completion of the read. The file system regains control immediately even if the disk must be accessed to retrieve the page. While pinned, a page's physical address is not altered.

ReadAheadsPerSec
Data type: uint32
Access type: Read-only
Qualifiers: DisplayName ("Read Aheads/sec") , CounterType (272696320) , DefaultScale (0) , PerfDetail (200)

Frequency of read operations from the file system cache in which the cache detects sequential access to a file. The read aheads permit the data to be transferred in larger blocks than those being requested by the application, reducing the overhead per access.

SyncCopyReadsPerSec
Data type: uint32
Access type: Read-only
Qualifiers: DisplayName ("Sync Copy Reads/sec") , CounterType (272696320) , DefaultScale (0) , PerfDetail (400)

Frequency of read requests from pages of the file system cache that involve a memory copy of the data from the cache to the application buffer. The application regains control immediately even if the disk must be accessed to retrieve the page.

SyncDataMapsPerSec
Data type: uint32
Access type: Read-only
Qualifiers: DisplayName ("Sync Data Maps/sec") , CounterType (272696320) , DefaultScale (0) , PerfDetail (400)

Frequency that an application using a file system, such as NTFS, to map a page of a file into the file system cache to read the page and does not wait for the page to be retrieved if it is not in the main memory.

SyncFastReadsPerSec
Data type: uint32
Access type: Read-only
Qualifiers: DisplayName ("Sync Fast Reads/sec") , CounterType (272696320) , DefaultScale (-1) , PerfDetail (400)

Frequency of read requests from the file system cache that bypass the installed file system and retrieve the data directly from the cache. Normally, file I/O requests invoke the appropriate file system to retrieve data from a file, but this path permits direct retrieval of data from the cache without file system involvement if the data is in the cache. Even if the data is not in the cache, one invocation of the file system is avoided. If the data is not in the cache, the request (application program call) waits until the data has been retrieved from the disk.

SyncMDLReadsPerSec
Data type: uint32
Access type: Read-only
Qualifiers: DisplayName ("Sync MDL Reads/sec") , CounterType (272696320) , DefaultScale (0) , PerfDetail (400)

Frequency of read operations from the file system cache that use a Memory Descriptor List (MDL) to access the pages. The MDL contains the physical address of each page in the transfer, thus permitting Direct Memory Access (DMA) of the pages. If the accessed page(s) are not in the main memory, the calling application program does not wait for the pages to fault in from the disk.

SyncPinReadsPerSec
Data type: uint32
Access type: Read-only
Qualifiers: DisplayName ("Sync Pin Reads/sec") , CounterType (272696320) , DefaultScale (0) , PerfDetail (400)

Frequency of reading data into the file system cache preparatory to writing the data back to disk. Pages read in this fashion are pinned in memory at the completion of the read. The file system regains control immediately even if the disk must be accessed to retrieve the page. While pinned, a page's physical address is not altered.

Timestamp_Object
Data type: uint64
Access type: Read-only

Object-defined timestamp, defined by the provider. This property is inherited from Win32_Perf.

For more information about using uint64 values in scripts, see Scripting in WMI.

Timestamp_PerfTime
Data type: uint64
Access type: Read-only

High Performance counter timestamp. A value could be obtained by calling the Windows function QueryPerformanceCounter. This property is inherited from Win32_Perf.

For more information about using uint64 values in scripts, see Scripting in WMI.

Timestamp_Sys100NS
Data type: uint64
Access type: Read-only

Timestamp value in 100 nanosecond units. This property is inherited from Win32_Perf.

For more information about using uint64 values in scripts, see Scripting in WMI.

Remarks

All classes derived from Win32_Perf are designed to be used with a refresher object. For more information about how to create and use a refresher object in C++, see Accessing Performance Data in C++. For more information about how to create and use a refresher object using scripts, see Refreshing WMI Data in Scripts.

The performance class and property qualifiers determine how to interpret the class data. For more information, see Class Qualifiers for Performance Counter Classes and Property Qualifiers for Performance Counter Classes.

Examples

For script code examples, see WMI Tasks for Scripts and Applications and the TechNet ScriptCenter Script Repository.

For C++ code examples, see WMI C++ Application Examples.

Requirements

Minimum supported client

Windows XP

Minimum supported server

Windows Server 2003

Namespace

\root\CIMV2

DLL

WmiPerfInst.dll;
WbemPerf.dll on Windows Server 2003 and Windows XP

See also

Performance Counter Classes
Accessing WMI Preinstalled Performance Classes
WMI Tasks: Performance Monitoring
Accessing Performance Data in Script

 

 

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