I ran into a huge problem since a couple of weeks. I use an asp.net application hosted under IIS7 (W2008 SP1), and every couple of hours it starts to consume about 50% of the processor when there are probably no users. This is understandable since we use Quartz.net to create some applications, but we have not yet been able to reproduce the problem.
Here is a trace with JetBrains dotTrace 3.1 while the processor was high: http://mycenter.info/tmp/DotTraceSnapshot.zip
Usually the process spent on the processor is w3wp.exe, but over the past couple of days sqlserver (2008) and memcached (1.2.1 and updated on Monday to version 1.2.4 beta) also killed the processor. It is strange that several times memcached starts to consume 100%, and its statistics show that it is quiet, however it works fine when the request is made.
Here's the crash dump (or stack trace dump) w3wp using WinDbg: (based on this guide: http://blogs.technet.com/marcelofartura/archive/2006/09/15/troubleshooting-iis-100-cpu-issues- step-by-step-intermediary.aspx )
0:000> ~ . 0 Id: 1be4.1d3c Suspend: 1 Teb: 7ffdf000 Unfrozen 1 Id: 1be4.b1c Suspend: 1 Teb: 7ffde000 Unfrozen 2 Id: 1be4.12a0 Suspend: 1 Teb: 7ffdd000 Unfrozen 3 Id: 1be4.19d0 Suspend: 1 Teb: 7ffdc000 Unfrozen 4 Id: 1be4.1714 Suspend: 1 Teb: 7ffd7000 Unfrozen 5 Id: 1be4.1a18 Suspend: 1 Teb: 7ffd6000 Unfrozen 6 Id: 1be4.12ac Suspend: 1 Teb: 7ffd5000 Unfrozen 7 Id: 1be4.dec Suspend: 1 Teb: 7ffd4000 Unfrozen 8 Id: 1be4.1e48 Suspend: 1 Teb: 7ffd8000 Unfrozen 9 Id: 1be4.1ca8 Suspend: 1 Teb: 7ffd3000 Unfrozen 10 Id: 1be4.1508 Suspend: 1 Teb: 7ffaf000 Unfrozen 11 Id: 1be4.1bc0 Suspend: 1 Teb: 7ffae000 Unfrozen 12 Id: 1be4.1f48 Suspend: 1 Teb: 7ffad000 Unfrozen 13 Id: 1be4.1994 Suspend: 1 Teb: 7ffac000 Unfrozen 14 Id: 1be4.1a48 Suspend: 1 Teb: 7ffab000 Unfrozen 15 Id: 1be4.12c8 Suspend: 1 Teb: 7ffa8000 Unfrozen 16 Id: 1be4.e44 Suspend: 1 Teb: 7ffa7000 Unfrozen 17 Id: 1be4.19e0 Suspend: 1 Teb: 7ffa6000 Unfrozen 18 Id: 1be4.19b0 Suspend: 1 Teb: 7ffa2000 Unfrozen 19 Id: 1be4.1b30 Suspend: 1 Teb: 7ffd9000 Unfrozen 20 Id: 1be4.1bfc Suspend: 1 Teb: 7ffa3000 Unfrozen 21 Id: 1be4.1be8 Suspend: 1 Teb: 7ffa1000 Unfrozen 22 Id: 1be4.1a54 Suspend: 1 Teb: 7ffa5000 Unfrozen 23 Id: 1be4.b74 Suspend: 1 Teb: 7ff3d000 Unfrozen 24 Id: 1be4.19b4 Suspend: 1 Teb: 7ff3c000 Unfrozen 25 Id: 1be4.1460 Suspend: 1 Teb: 7ffdb000 Unfrozen 26 Id: 1be4.1eac Suspend: 1 Teb: 7ffaa000 Unfrozen 27 Id: 1be4.1b90 Suspend: 1 Teb: 7ffa4000 Unfrozen 0:023> #23s Search address set to 77dc9a94 *** WARNING: Unable to verify checksum for SMDiagnostics.ni.dll *** WARNING: Unable to verify checksum for System.Data.ni.dll *** ERROR: Module load completed but symbols could not be loaded for Microsoft.Web.Services3.DLL *** WARNING: Unable to verify checksum for System.Windows.Forms.ni.dll *** WARNING: Unable to verify checksum for System.Web.ni.dll *** WARNING: Unable to verify checksum for Ademy.UI.Web.DLL *** ERROR: Module load completed but symbols could not be loaded for AjaxControlToolkit.DLL *** ERROR: Module load completed but symbols could not be loaded for 7zSharp.DLL *** WARNING: Unable to verify checksum for mscorlib.ni.dll *** ERROR: Module load completed but symbols could not be loaded for Iesi.Collections.DLL *** WARNING: Unable to verify checksum for System.Design.ni.dll *** WARNING: Unable to verify checksum for System.Core.ni.dll *** WARNING: Unable to verify checksum for Ademy.Event.DLL *** WARNING: Unable to verify checksum for System.ServiceModel.ni.dll *** ERROR: Module load completed but symbols could not be loaded for System.ServiceModel.ni.dll *** WARNING: Unable to verify checksum for App_Theme_Ocean.wgubmrqt.dll *** WARNING: Unable to verify checksum for NHibernate.Burrow.AppBlock.DLL *** ERROR: Module load completed but symbols could not be loaded for NHibernate.Burrow.AppBlock.DLL *** WARNING: Unable to verify checksum for NHibernate.Caches.SysCache2.DLL *** ERROR: Module load completed but symbols could not be loaded for NHibernate.Caches.SysCache2.DLL *** WARNING: Unable to verify checksum for Ademy.UI.Web.Controls.DLL *** WARNING: Unable to verify checksum for Microsoft.JScript.ni.dll *** WARNING: Unable to verify checksum for System.Web.Mobile.ni.dll *** WARNING: Unable to verify checksum for System.Runtime.Serialization.ni.dll ^ Memory access error in '#23s' 0:023> kb ChildEBP RetAddr Args to Child 11c6ede4 77dc8ed4 766bc622 0000038c 00000000 ntdll!KiFastSystemCallRet 11c6ede8 766bc622 0000038c 00000000 11c6ee20 ntdll!NtSetEvent+0xc 11c6edf8 011011ef 0000038c 7f52be6e 0fda4888 kernel32!SetEvent+0x10 WARNING: Frame IP not in any known module. Following frames may be wrong. 11c6ee20 71b26ffe 060c5f9c 010039b0 010628a0 0x11011ef *** WARNING: Unable to verify checksum for System.ni.dll 11c6ee4c 712c4b14 02528958 060c5f9c 11c6ee94 mscorlib_ni+0x216ffe 11c6ee5c 712c4abe 060c5fb0 02528958 060c600c System_ni+0x144b14 11c6ee94 71679260 060c5d24 7167926d 060c5d24 System_ni+0x144abe 11c6eec8 717d8373 060c5d24 11c6f3e8 712c4ce4 System_ni+0x4f9260 11c6ef14 712c4ce4 00000000 02528930 11c6ef74 System_ni+0x658373 11c6ef54 7129dbcb 098b6ac4 11c6efec 72f7eff8 System_ni+0x144ce4 11c6efa4 71b26d66 02df349c 11c6efc0 71b45681 System_ni+0x11dbcb 11c6efb0 71b45681 00000000 0dcfd2d8 11c6efd0 mscorlib_ni+0x216d66 11c6efc0 72f11b4c 766b45f1 00000000 11c6f050 mscorlib_ni+0x235681 11c6efd0 72f221f9 11c6f0a0 00000000 11c6f070 mscorwks!CallDescrWorker+0x33 11c6f050 72f36571 11c6f0a0 00000000 11c6f070 mscorwks!CallDescrWorkerWithHandler+0xa3 11c6f194 72f365a4 71a91ff0 11c6f2c8 11c6f1e8 mscorwks!MethodDesc::CallDescr+0x19c 11c6f1b0 72f365c2 71a91ff0 11c6f2c8 11c6f1e8 mscorwks!MethodDesc::CallTargetWorker+0x1f 11c6f1c8 7302a471 11c6f1e8 68e9b644 0dcfd2d8 mscorwks!MethodDescCallSite::CallWithValueTypes+0x1a 11c6f394 7302a5c6 11c6f424 68e9b194 02df34e4 mscorwks!ExecuteCodeWithGuaranteedCleanupHelper+0x9f 11c6f444 71b45577 11c6f3e8 02df17d0 01c177f8 mscorwks!ReflectionInvocation::ExecuteCodeWithGuaranteedCleanup+0x10f
Thanks in advance for any feedback!
UPDATE:
Here is a managed stack of hanging thread: I think it looks like a memcached provider, but still not sure what to do.
0:023> !clrstack OS Thread Id: 0xb74 (23) ESP EIP 11c6ee38 77dc9a94 [NDirectMethodFrameStandaloneCleanup: 11c6ee38] Microsoft.Win32.Win32Native.SetEvent(Microsoft.Win32.SafeHandles.SafeWaitHandle) 11c6ee48 71b26ffe System.Threading.EventWaitHandle.Set() 11c6ee54 712c4b14 System.Net.TimerThread.Prod() 11c6ee64 712c4abe System.Net.TimerThread+TimerQueue.CreateTimer(Callback, System.Object) 11c6eea0 71679260 System.Net.ConnectionPool.CleanupCallbackWrapper(Timer, Int32, System.Object) 11c6eed4 717d8373 System.Net.TimerThread+TimerNode.Fire() 11c6ef1c 712c4ce4 System.Net.TimerThread+TimerQueue.Fire(Int32 ByRef) 11c6ef5c 7129dbcb System.Net.TimerThread.ThreadProc() 11c6efac 71b26d66 System.Threading.ThreadHelper.ThreadStart_Context(System.Object) 11c6efb8 71b45681 System.Threading.ExecutionContext.runTryCode(System.Object) 11c6f3e8 72f11b4c [HelperMethodFrame_PROTECTOBJ: 11c6f3e8] System.Runtime.CompilerServices.RuntimeHelpers.ExecuteCodeWithGuaranteedCleanup(TryCode, CleanupCode, System.Object) 11c6f450 71b45577 System.Threading.ExecutionContext.RunInternal(System.Threading.ExecutionContext, System.Threading.ContextCallback, System.Object) 11c6f46c 71b301c5 System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext, System.Threading.ContextCallback, System.Object) 11c6f484 71b26ce4 System.Threading.ThreadHelper.ThreadStart() 11c6f6b0 72f11b4c [GCFrame: 11c6f6b0] 11c6f9a0 72f11b4c [ContextTransitionFrame: 11c6f9a0]
SOLUTION FOUND:
This happened due to an error in memcached 1.2.1 for Win32 when running on Windows 2008. I updated v1.2.6 and it worked. I assume I saw the w3wp process because the library that I use to connect to memcached has a rewrite process that hung even when memcached was still responding.
SOLUTION 2 FOUND:
If the first solution does not work, read THIS POST . I think the memcached solution just hides the real problem, which was a bug in SmtpClient.