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WMI Win32_PerfRawData 计数器类型使用详解

WMI 的Win32_PerfRawData 为我们提供了监控系统性能的相关参数。但是有些时候这些类的属性返回值不能直接使用。比如在监控网卡流量Win32_PerfRawData_Tcpip_NetworkInterface 时 BytesReceivedPersec BytesSentPersec 有时候会返回负值。难道是程序出错了么？其实其原因是，Win32_PerfRawData 类正如其名称所暗示的：它们是“原始”数据类，这意味着返回的值并不一定是最终的值。您通常需要对其进行“修正”；也就是说，您必须通过某种数学公式对返回的数值进行计算以便获得真正的值。
    那数学公式到底是什么呢？WMI把各种性能参数按照性能计数器类型。不同计数器类型使用不同的公式。具体分类如下:
计数器类型 XP 上的实例 2003 上的实例
PERF_COUNTER_RAWCOUNT 475 750
PERF_COUNTER_COUNTER 211 320
PERF_COUNTER_LARGE_RAWCOUNT 97 122
PERF_COUNTER_BULK_COUNT 63 78
PERF_RAW_FRACTION 13 30
PERF_100NSEC_TIMER 23 23
PERF_PRECISION_100NS_TIMER 8 8
PERF_AVERAGE_BULK 6 6
PERF_AVERAGE_TIMER 6 6
PERF_COUNTER_100NS_QUELEN_TYPE 6 6
PERF_SAMPLE_FRACTION 0 5
PERF_ELAPSED_TIME 4 4
PERF_COUNTER_TIMER 0 2
PERF_100NSEC_TIMER_INV 1 1
PERF_COUNTER_RAWCOUNT_HEX 1 1
PERF_COUNTER_LARGE_RAWCOUNT_HEX 1 1
PERF_COUNTER_LARGE_QUELEN_TYPE 0 0
PERF_COUNTER_TIMER_INV 0 0
PERF_COUNTER_TEXT 0 0
PERF_COUNTER_MULTI_TIMER_INV 0 0
PERF_COUNTER_DELTA 0 0
PERF_COUNTER_LARGE_DELTA 0 0
PERF_SAMPLE_COUNTER 0 0
PERF_COUNTER_QUELEN_TYPE 0 0
PERF_PRECISION_SYSTEM_TIMER 0 0
PERF_OBJ_TIME_TIMER 0 0
PERF_COUNTER_MULTI_TIMER 0 0
PERF_100NSEC_MULTI_TIMER 0 0
PERF_100NSEC_MULTI_TIMER_INV 0 0
PERF_COUNTER_OBJ_TIME_QUELEN_TYPE 0 0
如果看一下该表，您会发现一些有趣的事情：六种计数器类型（PERF_COUNTER_RAWCOUNT、PERF_COUNTER_COUNTER、 PERF_COUNTER_LARGE_RAWCOUNT、PERF_COUNTER_BULK_COUNT、PERF_RAW_FRACTION 和 PERF_100NSEC_TIMER）几乎涵盖了 Windows XP 和 Windows Server 2003 上使用的所有性能计数器。这六种类型中PERF_COUNTER_RAWCOUNT 和 PERF_COUNTER_LARGE_RAWCOUNT不需要任何计算；您可以直接使用返回的值。PERF_COUNTER_COUNTER 和 PERF_COUNTER_BULK_COUNT使用相同的公式。我们只需了解三个公式。这样，就将能够监视性能输出争取的返回值
具体那个类型对应那个公式如下：

PERF_RAW_FRACTION

(100 * CounterValue) / BaseValue
BaseValue 可以通过wbemtest.exe去查
PERF_COUNTER_COUNTER
(CounterValue2 - CounterValue1) / ((TimeValue2 - TimeValue1) / TimeBase)

  • TimeStamp_PerfTime。这是我们的开始时间（即，TimeValue)
  • Frequency_PerfTime。这是我们的 TimeBase
    • 具体的例子如下:
    On Error Resume Next
    strComputer = "."
    Set objArgs = wscript.Arguments
    strComputer = objArgs.item(0)
    Set objWMIService = GetObject("winmgmts:\\" & strComputer & "\root\cimv2")
    wqlQuery = "select * from Win32_PerfRawData_Tcpip_NetworkInterface where Name='Broadcom BCM5708C NetXtreme II GigE [NDIS VBD Client] - 数据包计划程序微型端口'" '查询指定网卡接口的实例
    Set colItems = objWMIService.ExecQuery(wqlQuery ,,48)
    For Each objItem in colItems
        recieve_value1=objItem.BytesReceivedPersec
        send_value1=objItem.BytesSentPersec
        timevalue1=objItem.Timestamp_PerfTime
        timeBase = objItem.Frequency_PerfTime
    Next
    Wscript.Sleep(1000)
    Set colItems = objWMIService.ExecQuery(wqlQuery ,,48)
    For Each objItem in colItems
        recieve_value2=objItem.BytesReceivedPersec
        send_value2=objItem.BytesSentPersec
        timevalue2=objItem.Timestamp_PerfTime
    Next
    recieve=(recieve_value2-recieve_value1)/CInt((timevalue2-timevalue1)/timeBase)
    send=(send_value2-send_value1)/CInt((timevalue2-timevalue1)/timeBase)
    wscript.echo CStr(send)
    wscript.echo CStr(recieve)
    wscript.echo Date() & " " & Time()
    wscript.echo "send kbps"
    wscript.echo "recieve kbps"
     

    PERF_100NSEC_TIMER

    100* (CounterValue2 - CounterValue1) / (TimeValue2 - TimeValue1)
使用 TimeStamp_Sys100NS 来确定时间间隔，而不是使用 TimeStamp_PerfTime 属性
    查询性能计数器类型的方法如下
    strComputer = "."
strNamespace = "root\cimv2"
Set objWMIService = GetObject("winmgmts:\\" & strComputer & "\root\cimv2")
    
For Each objclass2 in objWMIService.SubclassesOf()
    If Left(objClass2.Path_.Class,13) = "Win32_PerfRaw" Then
        strClass = objClass2.Path_.Class     
        Set objClass = GetObject("winmgmts:\\" & strComputer & _
            "\" & strNameSpace & ":" & strClass)
        For Each objClassProperty In objClass.Properties_
            strType = ""
            strFormula = ""
            For Each objClassQualifier In objClassProperty.Qualifiers_
                If objClassQualifier.Name = "countertype" Then
                Select Case objClassQualifier.Value
                    Case 0 
                        strType = "PERF_COUNTER_RAWCOUNT_HEX"
                    Case 1073874176
                        strType = "PERF_AVERAGE_BULK"
                    Case 1073939457
                        strType = "PERF_SAMPLE_BASE"
                    Case 1073939458
                        strType = "PERF_AVERAGE_BASE"
                    Case 1073939459
                        strType = "PERF_RAW_BASE"
                    Case 1073939712
                        strType = "PERF_LARGE_RAW_BASE"
                    Case 1107494144
                        strType = "PER_COUNTER_MULTI_BASE"
                    Case 256
                        strType = "PERF_COUNTER_LARGE_RAWCOUNT_HEX"
                    Case 272696320
                        strType = "PERF_COUNTER_COUNTER"
                    Case 272696576
                        strType = "PERF_COUNTER_BULK_COUNT"
                    Case 2816
                        strType = "PERF_COUNTER_TEXT"
                    Case 591463680
                        strType = "PERF_COUNTER_MULTI_TIMER_INV"
                    Case 4195238
                        strType = "PERF_COUNTER_DELTA"
                    Case 4195584
                        strType = "PERF_COUNTER_LARGE_DELTA"
                    Case 4260864
                        strType = "PERF_SAMPLE_COUNTER"
                    Case 4523008
                        strType = "PERF_COUNTER_QUELEN_TYPE"
                    Case 537003008
                        strType = "PERF_RAW_FRACTION"
                    Case 541525248
                        strType = "PERF_PRECISION_SYSTEM_TIMER"
                    Case 558957824
                        strType = "PERF_100NSEC_TIMER_INV"
                    Case 542180608
                        strType = "PERF_100NSEC_TIMER"
                    Case 542573824
                        strType = "PERF_PRECISION_100NS_TIMER"
                    Case 543229184
                        strType = "PERF_OBJ_TIME_TIMER"
                    Case 549585920
                        strType = "PERF_SAMPLE_FRACTION"
                    Case 4523264
                        strType = "PERF_COUNTER_LARGE_QUELEN_TYPE"
                    Case 5571840
                        strType = "PERF_COUNTER_100NS_QUELEN_TYPE"
                    Case 541132032
                        strType = "PERF_COUNTER_TIMER"
                    Case 574686464
                        strType = "PERF_COUNTER_MULTI_TIMER"
                    Case 575735040
                        strType = "PERF_100NSEC_MULTI_TIMER"
                    Case 592512256
                        strType = "PERF_100NSEC_MULTI_TIMER_INV"
                    Case 65536
                        strType = "PERF_COUNTER_RAWCOUNT"
                    Case 65792
                        strType = "PERF_COUNTER_LARGE_RAWCOUNT"
                    Case 6620416
                        strType = "PERF_COUNTER_OBJ_TIME_QUELEN_TYPE"
                    Case 805438464
                        strType = "PERF_AVERAGE_TIMER"
                    Case 807666944
                        strType = "PERF_ELAPSED_TIME"
                    Case 557909248
                        strType = "PERF_COUNTER_TIMER_INV"
                    Case Else
                        strType = "无法确定计数器类型。"
                    End Select
                End If
            Next
            WScript.Echo strClass & "." & objClassProperty.Name & "," & strType
        Next
    End If
Next
    [wangjy17908]
    添加时间：2010-04-08
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