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Property Qualifiers for Performance Counter Classes

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Property qualifiers specify information about the performance counter to which the property maps.

The performance counter is part of a performance object represented by a WMI performance counter class Performance counter–specific qualifiers are automatically attached by the WbemPerfClass provider to Win32_PerfRawData classes and properties in Root\CIMv2.

This information applies to all instances of the performance class. Some qualifiers with Boolean values that are always false may not be present on specific classes.

Property Qualifiers for Raw and Formatted Performance Classes

The following list lists qualifiers that apply to properties in classes that are derived either from Win32_PerfRawData or Win32_PerfFormattedData.

CounterType

sint32

Integer value in the counter type enumeration, as defined in Winperf.h or Perflib.h. The CounterTypequalifier indicates the formula or algorithm used to calculate the value shown in System Monitor for the counter which the property represents.

DisplayName

string

The performance Counter name, as specified by Performance Data Helper (PDH).

HelpIndex

sint32

Not used. Always contains 0.

PerfIndex

sint32

Not used. Always contains 0.

Property Qualifiers for Raw Performance Classes

The following list lists qualifiers that apply to all properties of classes that are derived from Win32_PerfRawData.

PerfDefault

boolean

Indicates whether this property is the default counter to use in list boxes. This qualifier defaults to False for Performance Counters Version 6.0 because they do not supply data for it. For more information, see Performance Counters.

DefaultScale

sint32

Power of 10 to use for display of the counter. For zero, the estimated maximum is 10^0, or 1.

PerfDetail

sint32

Audience level of knowledge. Not used. The value is always 100.

Property Qualifiers for Formatted Performance Classes

The following list lists qualifiers that apply to all properties of classes that are derived from Win32_PerfFormattedData.

CookingType

string

Formula type used to produce the result. Each counter type uses the other property qualifiers to calculate the result shown as the value of the current property. The Counter, PerfTimeStamp, and PerfTimeFreq qualifiers map to properties in a raw class which supply the data.

For more information, see CounterType Qualifier.

Counter

string

Name of a required property in the corresponding raw class to use as the counter value in the cooking formula. The value must be the property name of the data source property in the corresponding raw class.

PerfTimeStamp

string

Name of a property in a raw class to use as a frequency in the cooking formula. The appropriate default value at the class level will be used if this qualifier is not present for the property. The frequency represents the ticks per second of the time stamp.

PerfTimeFreq

string

Name of a property in a raw class to use as a timestamp in the cooking formula. The appropriate default value at the class level is used if this qualifier is not present for the property. An automatically generated time stamp may introduce error in a calculation because the timestamp is an approximation and does not account for overhead incurred by marshaling and actual data collection.

How to Interpret Property Qualifiers

Properties in the Win32_PerfFormattedData classes contain the calculated data supplied by the Formatted Performance Data Provider. The property value is the final calculated result. The qualifiers supply a recipe.

The Counter and Base qualifiers point to the sources of data and CookingType specifies the formula used to produce the result. The timestamp and sample frequency also come from the corresponding raw class and are named in PerfTimeStamp and PerfTimeFreq.

For example, one of the formatted classes supplied by WMI, Win32_PerfFormattedData_PerfDisk_LogicalDisk, contains a property named AvgDiskBytesPerRead. The name of the property in the formatted class must be the same as the property in the raw class. The AvgDiskBytesPerRead property has the following qualifiers.

The following list lists the available property qualifiers for properties of all classes derived from Win32_PerfFormattedData.

Qualifier Value
CookingType PERF_AVERAGE_BULK
Counter AvgDiskBytesPerRead
PerfTimeStamp Timestamp_PerfTime
PerfTimeFreq Frequency_PerfTime
PerfIndex 408
HelpIndex 409
Base AvgDiskBytesPerRead_Base

 

The AvgDiskBytesPerRead property reports the average number of bytes transferred from the disk during read operations. The formula for PERF_AVERAGE_BULK is:

(Sample2 - Sample1) / (Base Sample2 - Base Sample1)

The read operation is sampled at the frequency specified by PerfTimeFreq with the PerfTimeStamp value indicating the most recent sample. The raw counter data in bytes is taken from the AvgDiskBytesPerRead property in the Win32_PerfRawData_PerfDisk_LogicalDisk class. The base number of operations data is taken from the AvgDiskBytesPerRead_Base property in that same class.

For more information, see Obtaining Statistical Performance Data and Monitoring Performance Data.

Monitoring Performance Data

Qualifiers Specific to WMI Performance Classes

Performance Counter Classes

Accessing WMI Preinstalled Performance Classes

WMI Tasks: Performance Monitoring