.NET 3.5 application High CPU usage indicated by mscorwks.dll InitializeFusion

Question

Our .NET 3.5 C# wpf client application running on a Windows 7 machine is consuming a lot of CPU and when we use process explorer to look into the process we see that a bunch of threads with the start address of mscorwks.dll!InitialzeFusion. These threads are consuming a large percentage of the cpu cycles. Any ideas how I can diagnose/debug what exactly these threads are doing?

It may be useful to note that I see 55 threads running at this point and about 20 are actively consuming CPU while the others seem to not be doing anything.

This is the stack from one of the threads:

USER32.dll!SystemParametersInfoW+0xc9

USER32.dll!IsProcessDPIAware+0x1d1

ntdll.dll!KiUserCallbackDispatcher+0x1f

USER32.dll!SfmDxSetSwapChainStats+0x1a

USER32.dll!GetMessageW+0x2a

mscorwks.dll!IEE+0xd23b

WindowsBase.ni.dll+0x11179b

WindowsBase.ni.dll+0x11e517

WindowsBase.ni.dll+0x117735

WindowsBase.ni.dll+0x1175ee

Answer 1

Is this the problem you're having? If so, the forum mentions several solutions and one of them is to apply patch Windows6.1-KB981574-v2-x64. The forum also discusses a similar case: http://social.technet.microsoft.com/Forums/en-US/ilm2/thread/0ed2ab1f-0dd3-4cbf-895d-67136a77cc96