My post on autoConfig triggered and interesting discussion with my colleague Cenk about which is the real effect of this setting; one of his customers asked what to do if they needed to adjust only one or two values and not all the ones discussed in Contention, poor performance, and deadlocks when you make Web service requests from ASP.NET applications, they wanted to be sure they could change only what they needed to fine tune and forget about the rest. The short answer is: you can change only what you need to and leave he rest as is, since we have default values hardcoded to improve performance so you’re safe (provided the values you’re changing make sense in the context, of course).
If we have a look at System.Web.Configuration.ProcessModelSection with Windbg, we can see all the properties we have in <processModel> and _defaultValue corresponds to the defaults we have in machine.config.comments:
0:000> !do 06904868 Name: System.Web.Configuration.ProcessModelSection MethodTable: 6638dcb0 EEClass: 663a0604 Size: 64(0x40) bytes (C:\Windows\assembly\GAC_32\System.Web\2.0.0.0__b03f5f7f11d50a3a\System.Web.dll) Fields: MT Field Offset Type VT Attr Value Name 7910be50 400014d 30 System.Boolean 1 instance 0 _bDataToWrite 7910be50 400014e 31 System.Boolean 1 instance 0 _bModified 7910be50 400014f 32 System.Boolean 1 instance 1 _bReadOnly 7910be50 4000150 33 System.Boolean 1 instance 0 _bElementPresent 7910be50 4000151 34 System.Boolean 1 instance 1 _bInited 648eff64 4000152 4 ...ionLockCollection 0 instance 00000000 _lockedAttributesList 648eff64 4000153 8 ...ionLockCollection 0 instance 00000000 _lockedAllExceptAttributesList 648eff64 4000154 c ...ionLockCollection 0 instance 00000000 _lockedElementsList 648eff64 4000155 10 ...ionLockCollection 0 instance 00000000 _lockedAllExceptElementsList 648ea704 4000156 14 ...nfigurationValues 0 instance 069048a8 _values 790fd8c4 4000157 18 System.String 0 instance 00000000 _elementTagName 648f032c 4000158 1c ...lementInformation 0 instance 00000000 _evaluationElement 648eee30 4000159 20 ...onElementProperty 0 instance 068fce20 _elementProperty 648f53d0 400015a 2c System.Int32 1 instance 0 _fItemLocked 648f0a48 400015b 24 ...ontextInformation 0 instance 00000000 _evalContext 648eda8c 400015c 28 ...nfigurationRecord 0 instance 028bea78 _configRecord 7912d8f8 4000148 8 System.Object[] 0 shared static s_lockAttributeNames >> Domain:Value 023d04b0:NotInit 024169d0:068fcd1c << 79101fe4 4000149 c ...ections.Hashtable 0 shared static s_propertyBags >> Domain:Value 023d04b0:NotInit 024169d0:068fcd40 << 00000000 400014a 10 0 shared static s_perTypeValidators >> Domain:Value 023d04b0:NotInit 024169d0:00000000 << 790fd0f0 400014b 14 System.Object 0 shared static s_nullPropertyValue >> Domain:Value 023d04b0:NotInit 024169d0:068fce08 << 648eee30 400014c 18 ...onElementProperty 0 shared static s_ElementProperty >> Domain:Value 023d04b0:NotInit 024169d0:068fce20 << 648eee84 400015d 38 ...ectionInformation 0 instance 069049b8 _section 648eee30 4001928 74c ...onElementProperty 0 shared static s_elemProperty >> Domain:Value 023d04b0:NotInit 024169d0:06903da8 << 7911228c 4001929 748 System.TimeSpan 1 shared static DefaultClientConnectedCheck >> Domain:Value 023d04b0:NotInit 024169d0:06903850 << 648ef118 400192a 750 ...ropertyCollection 0 shared static _properties >> Domain:Value 023d04b0:NotInit 024169d0:06904714 << 648ef05c 400192b 754 ...igurationProperty 0 shared static _propEnable >> Domain:Value 023d04b0:NotInit 024169d0:06903db4 << 648ef05c 400192c 758 ...igurationProperty 0 shared static _propTimeout >> Domain:Value 023d04b0:NotInit 024169d0:06903df4 << 648ef05c 400192d 75c ...igurationProperty 0 shared static _propIdleTimeout >> Domain:Value 023d04b0:NotInit 024169d0:06903e38 << 648ef05c 400192e 760 ...igurationProperty 0 shared static _propShutdownTimeout >> Domain:Value 023d04b0:NotInit 024169d0:06903e7c << 648ef05c 400192f 764 ...igurationProperty 0 shared static _propRequestLimit >> Domain:Value 023d04b0:NotInit 024169d0:06903ed8 << 648ef05c 4001930 768 ...igurationProperty 0 shared static _propRequestQueueLimit >> Domain:Value 023d04b0:NotInit 024169d0:06903f74 << 648ef05c 4001931 76c ...igurationProperty 0 shared static _propRestartQueueLimit >> Domain:Value 023d04b0:NotInit 024169d0:06903ff8 << 648ef05c 4001932 770 ...igurationProperty 0 shared static _propMemoryLimit >> Domain:Value 023d04b0:NotInit 024169d0:06904064 << 648ef05c 4001933 774 ...igurationProperty 0 shared static _propWebGarden >> Domain:Value 023d04b0:NotInit 024169d0:069040a4 << 648ef05c 4001934 778 ...igurationProperty 0 shared static _propCpuMask >> Domain:Value 023d04b0:NotInit 024169d0:069040e4 << 648ef05c 4001935 77c ...igurationProperty 0 shared static _propUserName >> Domain:Value 023d04b0:NotInit 024169d0:06904118 << 648ef05c 4001936 780 ...igurationProperty 0 shared static _propPassword >> Domain:Value 023d04b0:NotInit 024169d0:0690414c << 648ef05c 4001937 784 ...igurationProperty 0 shared static _propLogLevel >> Domain:Value 023d04b0:NotInit 024169d0:06904180 << 648ef05c 4001938 788 ...igurationProperty 0 shared static _propClientConnectedCheck >> Domain:Value 023d04b0:NotInit 024169d0:069041d4 << 648ef05c 4001939 78c ...igurationProperty 0 shared static _propComAuthenticationLevel >> Domain:Value 023d04b0:NotInit 024169d0:06904218 << 648ef05c 400193a 790 ...igurationProperty 0 shared static _propComImpersonationLevel >> Domain:Value 023d04b0:NotInit 024169d0:0690426c << 648ef05c 400193b 794 ...igurationProperty 0 shared static _propResponseDeadlockInterval >> Domain:Value 023d04b0:NotInit 024169d0:069042c0 << 648ef05c 400193c 798 ...igurationProperty 0 shared static _propResponseRestartDeadlockInterval >> Domain:Value 023d04b0:NotInit 024169d0:06904304 << 648ef05c 400193d 79c ...igurationProperty 0 shared static _propAutoConfig >> Domain:Value 023d04b0:NotInit 024169d0:06904348 << 648ef05c 400193e 7a0 ...igurationProperty 0 shared static _propMaxWorkerThreads >> Domain:Value 023d04b0:NotInit 024169d0:069043ac << 648ef05c 400193f 7a4 ...igurationProperty 0 shared static _propMaxIOThreads >> Domain:Value 023d04b0:NotInit 024169d0:0690443c << 648ef05c 4001940 7a8 ...igurationProperty 0 shared static _propMinWorkerThreads >> Domain:Value 023d04b0:NotInit 024169d0:069044cc << 648ef05c 4001941 7ac ...igurationProperty 0 shared static _propMinIOThreads >> Domain:Value 023d04b0:NotInit 024169d0:0690455c << 648ef05c 4001942 7b0 ...igurationProperty 0 shared static _propServerErrorMessageFile >> Domain:Value 023d04b0:NotInit 024169d0:069045c8 << 648ef05c 4001943 7b4 ...igurationProperty 0 shared static _propPingFrequency >> Domain:Value 023d04b0:NotInit 024169d0:069045fc << 648ef05c 4001944 7b8 ...igurationProperty 0 shared static _propPingTimeout >> Domain:Value 023d04b0:NotInit 024169d0:06904640 << 648ef05c 4001945 7bc ...igurationProperty 0 shared static _propMaxAppDomains >> Domain:Value 023d04b0:NotInit 024169d0:069046a8 << 79102290 4001946 938 System.Int32 1 shared static cpuCount >> Domain:Value 023d04b0:NotInit 024169d0:2 <<
0:000> !do 0690443c
Name: System.Configuration.ConfigurationProperty
MethodTable: 648ef05c
EEClass: 648eefec
Size: 52(0x34) bytes
(C:\Windows\assembly\GAC_MSIL\System.Configuration\2.0.0.0__b03f5f7f11d50a3a\System.Configuration.dll)
Fields:
MT Field Offset Type VT Attr Value Name
790fd8c4 4000277 4 System.String 0 instance 06903c08 _name
790fd8c4 4000278 8 System.String 0 instance 06903c08 _providedName
790fd8c4 4000279 c System.String 0 instance 00000000 _description
79106894 400027a 10 System.Type 0 instance 068b7554 _type
790fd0f0 400027b 14 System.Object 0 instance 06904430 _defaultValue
7a7588dc 400027c 18 …del.TypeConverter 0 instance 00000000 _converter
648ef1a0 400027d 2c System.Int32 1 instance 0 _options
648f022c 400027e 1c …tionValidatorBase 0 instance 06904418 _validator
790fd8c4 400027f 20 System.String 0 instance 00000000 _addElementName
790fd8c4 4000280 24 System.String 0 instance 00000000 _removeElementName
790fd8c4 4000281 28 System.String 0 instance 00000000 _clearElementName
648f022c 4000274 68 …tionValidatorBase 0 shared static NonEmptyStringValidator
>> Domain:Value 023d04b0:NotInit 024169d0:068fcc00 <<
648f022c 4000275 6c …tionValidatorBase 0 shared static DefaultValidatorInstance
>> Domain:Value 023d04b0:NotInit 024169d0:068fcc14 <<
790fd8c4 4000276 70 System.String 0 shared static DefaultCollectionPropertyName
>> Domain:Value 023d04b0:NotInit 024169d0:068fcbec <<
0:000> !do 06904430
Name: System.Int32
MethodTable: 79102290
EEClass: 79102218
Size: 12(0xc) bytes
(C:\Windows\assembly\GAC_32\mscorlib\2.0.0.0__b77a5c561934e089\mscorlib.dll)
Fields:
MT Field Offset Type VT Attr Value Name
79102290 40003e9 4 System.Int32 1 instance 20 m_value
<processModel enable = "true" [true|false] timeout = "10675199.02:48:05.4775807" [HH:MM:SS] idleTimeout = "10675199.02:48:05.4775807" [HH:MM:SS] shutdownTimeout = "00:00:05" [HH:MM:SS] requestLimit = "2147483647" [number] requestQueueLimit = "5000" [number] restartQueueLimit = "10" [number] memoryLimit = "60" [number] webGarden = "false" [true|false] cpuMask = "0xffffffff" [number] userName = "machine" [String] password = "AutoGenerate" [String] logLevel = "Errors" [None | All | Errors] clientConnectedCheck = "00:00:05" [HH:MM:SS] comAuthenticationLevel = "Connect" [None | Call | Connect | Default | Pkt | PktIntegrity | PktPrivacy] comImpersonationLevel = "Impersonate" [Default | Anonymous | Delegate | Identify | Impersonate] responseDeadlockInterval = "00:03:00" [HH:MM:SS] responseRestartDeadlockInterval = "00:03:00" [HH:MM:SS] autoConfig = "false" [true|false] maxWorkerThreads = "20" [number] maxIoThreads = "20" [number] minWorkerThreads = "1" [number] minIoThreads = "1" [number] serverErrorMessageFile = "" [String] pingFrequency = "10675199.02:48:05.4775807" [HH:MM:SS] pingTimeout = "10675199.02:48:05.4775807" [HH:MM:SS] maxAppDomains = "2000" [number] />
Internally to debug managed code we use a Windbg extension which works well with private symbols and has some additional commands the public sos.dll does not have and one of those shows the ThreadPool configuration, very useful to have a quick report of those configuration values.
After the discussion I found myself thinking how to extract those values from a dump using only public symbols and the public sos extension everyone has access to; two of them are quite easy to find out (you can get a full list of members of ThreadpoolMgr class running mscorwks!ThreadpoolMgr*):
0:000> ?poi(mscorwks!ThreadpoolMgr::NumberOfProcessors) Evaluate expression: 2 = 00000002 0:000> ?poi(mscorwks!ThreadpoolMgr::MaxLimitTotalWorkerThreads) Evaluate expression: 200 = 000000c8
From System.Web.RequestQueue we can get _minLocalFreeThreads, _minExternFreeThreads and _queueLimit (RequestQueueLimit):
Name: System.Web.RequestQueue
MethodTable: 663aebf0
EEClass: 663aeb80
Size: 64(0x40) bytes
(C:\Windows\assembly\GAC_32\System.Web\2.0.0.0__b03f5f7f11d50a3a\System.Web.dll)
Fields:
MT Field Offset Type VT Attr Value Name
79102290 4001203 14 System.Int32 1 instance 176 _minExternFreeThreads
79102290 4001204 18 System.Int32 1 instance 152 _minLocalFreeThreads
79102290 4001205 1c System.Int32 1 instance 5000 _queueLimit
7911228c 4001206 2c System.TimeSpan 1 instance 0691da2c _clientConnectedTime
7910be50 4001207 28 System.Boolean 1 instance 1 _iis6
791087cc 4001208 4 ...Collections.Queue 0 instance 0691da40 _localQueue
791087cc 4001209 8 ...Collections.Queue 0 instance 0691daf4 _externQueue
79102290 400120a 20 System.Int32 1 instance 0 _count
791186fc 400120b c ...ding.WaitCallback 0 instance 0691dba8 _workItemCallback
79102290 400120c 24 System.Int32 1 instance 0 _workItemCount
7910be50 400120d 29 System.Boolean 1 instance 0 _draining
7911228c 400120e 34 System.TimeSpan 1 instance 0691da34 _timerPeriod
791127fc 400120f 10 ...m.Threading.Timer 0 instance 0691dbe8 _timer
I was trying to find a convenient way to get the remaining three values (autoConfig, maxConnection and Number of timers) when I found this post from Tom, and now my quest is over: !DumpThreadConfig is the same command we have in the internal Windbg extension I mentioned and also the output is the same… so apparently you just have to be patient and wait for the next Debugging Tools release ?
Carlo
Quote of the day:
There is nothing new under the sun but there are lots of old things we don’t know. – Ambrose Bierce