Re: Please help troubleshoot high CPU in classic ASP

lextm — Wed, 10 Jun 2009 10:50:54 GMT

DebugDiag did find something useful in the dump, but it cannot tell you the whole story.

I think you need to manually analyze the dump to gain more insights of the problem. Or if you need assistance, you can open a case via http://support.microsoft.com

Please help troubleshoot high CPU in classic ASP

artisticcheese — Tue, 09 Jun 2009 21:56:34 GMT

My server is quad-proc, for whatever reason only 1 CPU is used to process ASP page. I see 100 CPU utilization on 1 processor and others are idle.

I run DebugDiag and it come up with

Detected possible blocking or leaked critical section at 0x03391ef4 owned by thread 74 in dllhost.exe__IIS Out-Of-Process Pooled Applications__PID__4132__Date__06_09_2009__Time_01_03_50PM__953__Manual Dump.dmp

Impact of this lock

78.57% of threads blocked

(Threads 16 17 18 19 20 21 22 23 24 25 26 29 30 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118)

The following functions are trying to enter this critical section
ASP!CHitObj::ViperAsyncCallback+11c

The following module(s) are involved with this critical section
C:\WINNT\system32\inetsrv\ASP.DLL from Microsoft Corporation

Stack for thread 74 is below

Thread 74 - System ID 3664

Entry point	comsvcs!STAThread::STAThreadWorker
Create time	6/8/2009 3:18:01 PM
Time spent in user mode	0 Days 00:02:27.375
Time spent in kernel mode	0 Days 00:01:38.421

Function	Source
vbscript!rtConcatBstr+51
vbscript!VbsVarConcat+76
vbscript!CScriptRuntime::Run+1795
vbscript!CScriptEntryPoint::Call+5c
vbscript!CScriptRuntime::Run+1f08
vbscript!CScriptEntryPoint::Call+5c
vbscript!CScriptRuntime::Run+1f08
vbscript!CScriptEntryPoint::Call+5c
vbscript!CSession::Execute+b4
vbscript!COleScript::ExecutePendingScripts+13e
vbscript!COleScript::SetScriptState+150
ASP!CActiveScriptEngine::TryCall+15
ASP!CActiveScriptEngine::Call+4d
ASP!CallScriptFunctionOfEngine+48
ASP!ExecuteRequest+19e
ASP!Execute+17e
ASP!CHitObj::ViperAsyncCallback+452
ASP!CViperAsyncRequest::OnCall+3f
comsvcs!STAActivityWorkHelper+a
OLE32!EnterForCallback+6a
OLE32!SwitchForCallback+12f
OLE32!PerformCallback+50
OLE32!CObjectContext::InternalContextCallback+10d
OLE32!CObjectContext::DoCallback+1a
comsvcs!STAActivityWork::DoWork+75
comsvcs!STAThread::STAThreadWorker+423
KERNEL32!BaseThreadStart+52

ASP request executing on thread	74
GET request for	/MC/PTB/V7/Agent/myMain.asp
Request alive for	00:01:34
QueryString	Mode
Request mapped to	D:\M\MC\PTB\V7\AGENT\MYMAIN.ASP
ASP Application	/LM/W3SVC/1/Root
ASP Template	D:\M\MC\PTB\V7\AGENT\MYMAIN.ASP

Function Scope	Line Of Code	Source File	Line Number
AddBase64Chars	strOutput = strOutput & Mid( strAlphabet, iChar + 1, 1 )	D:\MVS\MC\PTB\BASE64.ASP	25
Base64Encode	AddBase64Chars strOutput, accum, cAccumulated	D:\MVS\MC\PTB\BASE64.ASP	51
Global Scope	Base64Encode ssv_policyXML, ssv_EncodedXML	D:\M\MC\PTB\V7\AGENT\MYMAIN.ASP	884

2 issues:

1. Why would requests be serialized to single thread?

2. What is causing this high CPU utilization. Source code for Base64 is below?

Thanks,

<%
'//////////////////////////////////////////////////////////////
'// Base64 Encode function
'//

Function AddBase64Chars( ByRef strOutput, ByVal accum, ByVal cAccumulated )
    ' The Base64 alphabet lookup table
    Dim strAlphabet
    strAlphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZ" & _
                  "abcdefghijklmnopqrstuvwxyz" & _
                  "0123456789+/"

Dim i, cToOutput

' Output characters is always input characters plus one
cToOutput = cAccumulated + 1

    For i = 1 To cToOutput
        ' Extract 6 bits of the accumulator at the appropriate position
        Dim iChar
        iChar = (accum \ (64 ^ (4 - i))) And 63

        ' Add Base64 character to output
        strOutput = strOutput & Mid( strAlphabet, iChar + 1, 1 )
    Next
    ' Add padding
    For i = 1 To 4 - cToOutput
        strOutput = strOutput & "="
    Next
End function

Function Base64Encode( ByVal strInput, ByRef strOutput )

strOutput = ""

    Dim i
    Dim accum, cAccumulated
    accum = 0
    cAccumulated = 0
    For i = 1 To LenB( strInput )
        ' Shift ASCII of input character up appropriate # of places and OR
        ' into the accumulator
        Dim ch
        ch = AscB( MidB( strInput, i, 1 ) )
        ch = ch * (256 ^ (2 - cAccumulated))
        accum = accum Or ch
        cAccumulated = cAccumulated + 1

        If cAccumulated = 3 Then
            AddBase64Chars strOutput, accum, cAccumulated
            cAccumulated = 0
            accum = 0
        End If
    Next
    If cAccumulated > 0 Then
        AddBase64Chars strOutput, accum, cAccumulated
    End If

End function
%>

Classic ASP

Re: Please help troubleshoot high CPU in classic ASP

Please help troubleshoot high CPU in classic ASP

Thread 74 - System ID 3664