VS2010 Debug entry very slow

Question

When I start debugging my web application either from Start with Debugging (F5) or attaching to the ASP.NET worker process it will load the assemblies from the application very slowly that I can individual read the names of them as they scroll through the status bar of VS2010.

When I start debugging I see that MSVSMON.exe uses 50% CPU and locks at 50% clearly filling up a full core. Also seeing that this is described as Visual Studio Remote Debugging Monitor, I'm confused if this should even be used since I'm debugging everything local to my machine.

I am running my environment virtually connected by RDP if that could be related to this.

Host Machine: Server 2008 Enterprise R2 Dualcore Xeon 2.53ghz

Virtual Instance: Win7 Enterprise 6gb ram full processor allocation

Does this seem normal? Should MSVSMON even be running if I'm debugging locally?

Answer 1

Yes, msvsmon.exe will be used when you debug a 64-bit program. Since Visual Studio is completely 32-bit, the remote debugger is needed to bridge the divide.

There isn't any reason to assume that the slowdown is caused by it being a remote debugger. Working mightily to find and load the .pdb files would be likely. Or accidentally having the mixed-mode debugging option turned on so the debugger is also seeing all unmanaged DLL loads and finding symbols for them. These are just guesses of course.

Answer 2

Menu.Debug.DeleteAllBreakpoints

Worked for me.

Answer 3

Searching for symbols is often very slow at the start of debug, particularly if you have one of the remote symbol options configured, and have not set 'ignores' on the various DLLs which will not have symbols on MS servers.

These can be not only things like 3rd party components of your code, but also hooks DLLs injected by, for example, graphics drivers, so it's worth keeping an eye on what's trying to load.

Running Fiddler ( http://www.fiddler2.com/fiddler2/ ) while starting debugging will show you if symbols are being fetched remotely.

Even if VS is not explicitly set (In tools->options-debug) for remote symbol fetch, it will still follow the _NT_SYMBOL_PATH environment variable - check if that's set, and what it points to.