Base Counter Types
Some formulas require both a counter property and base property. The base value is the denominator in the formula for the counter type. In raw data Performance Counter Classes derived from Win32_PerfRawData, the base property must immediately follow the counter property. The base property must have the same name as the preceding counter, with _Base appended.
For example, the AvgDiskBytesPerRead property in Win32_PerfRawData_PerfDisk_LogicalDisk contains the raw value, in bytes, transferred from the disk during read operations. It has a base property, AvgDiskBytesPerRead_Base, which represents the accumulated number of operations. When WMI applies the formula for the specified counter type, PERF_AVERAGE_BASE, AvgDiskBytesPerRead is divided by AvgDiskBytesPerRead_Base to produce the average value. This value appears in System Monitor and is stored in the corresponding Win32_PerfFormattedData_PerfDisk_LogicalDisk property. Base properties are only used in raw data classes.
In classes derived from Win32_PerfFormattedData, the Counter qualifier specifies the numerator property in the raw class and the Base qualifier specifies the base denominator property.
The following table lists the CounterType constant values.
| CounterType Constant | Description |
|---|---|
| PERF_AVERAGE_BASEDecimal 1073939458 |
Base value used to calculate the PERF_AVERAGE_TIMER and PERF_AVERAGE_BULK counter types. |
| PERF_COUNTER_MULTI_BASEDecimal 1107494144 |
Base value used to calculate the PERF_COUNTER_MULTI_TIMER, PERF_COUNTER_MULTI_TIMER_INV, PERF_100NSEC_MULTI_TIMER, and PERF_100NSEC_MULTI_TIMER_INV counter types. |
| PERF_LARGE_RAW_BASEDecimal 1073939712 |
Base value found in the calculation of PERF_RAW_FRACTION, 64 bits. |
| PERF_RAW_BASEDecimal 1073939459 |
Base value used to calculate the PERF_RAW_FRACTION counter type. |
| PERF_SAMPLE_BASEDecimal 1073939457 |
Base value used to calculate the PERF_SAMPLE_COUNTER and PERF_SAMPLE_FRACTION counter types. |