WPF to run AppDomain (Application.RunInternal, XamlReader.LoadBaml)

Question

I have a relatively simple application, but the warm (second, etc.) startup time is terrible 3-5 seconds. The profiler (VS2010, processor fetch) shows that more than 80% of the time is spent on the Application.RunInternal (~ 40%) and XamlRader.LoadBaml (~ 40%) functions.

The root of the problem is that Window is created in a non-standard AppDomain. If I move on to creating a window in AppDomain by default or grant Unlimited AppDomain permission, everything will be as fast as expected.

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I am testing:

• Windows Seven x64
• .Net 4.0
• 4Gb RAM
• GeForce 9800GT 1Gb.

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I create an appdomain this way

var permissionSet = new PermissionSet(null); permissionSet.AddPermission(new SecurityPermission(SecurityPermissionFlag.Execution | SecurityPermissionFlag.SerializationFormatter | SecurityPermissionFlag.UnmanagedCode)); permissionSet.AddPermission(new ReflectionPermission(PermissionState.Unrestricted)); permissionSet.AddPermission(new UIPermission(PermissionState.Unrestricted)); permissionSet.AddPermission(new MediaPermission(PermissionState.Unrestricted)); permissionSet.AddPermission(new FileDialogPermission(PermissionState.Unrestricted)); var appDomainSetup = new AppDomainSetup { ApplicationBase = AppDomain.CurrentDomain.SetupInformation.ApplicationBase, ApplicationName = AppDomain.CurrentDomain.SetupInformation.ApplicationName, DisallowApplicationBaseProbing = false, DisallowBindingRedirects = true, DisallowCodeDownload = true, DisallowPublisherPolicy = true, LoaderOptimization = LoaderOptimization.MultiDomainHost }; _appDomain = AppDomain.CreateDomain( name, null, appDomainSetup, permissionSet, new[] { // a few types I need typeof(...).Assembly.Evidence.GetHostEvidence<StrongName>(), }); 

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The behavior remains unchanged even if I delete XAML in an empty window

 <Window x:Class="Rosmurta.Extensibility.WpfUI.RosmurtaWindow" x:ClassModifier="internal" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Title="Test" Height="480" Width="640" WindowStyle="SingleBorderWindow"> <Grid> </Grid> </Window> 

Not too much to understand with XamlRader.LoadBaml, but it spends more than 30% of the startup time for an empty window.

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I tried (and it did not help)

• Adding <generatePublisherEvidence enabled = "false" /> to App.config.
• Adding the [LoaderOptimization (LoaderOptimization.MultiDomainHost)] attribute to the Main method.
• Adding signatures to all assemblies.

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What else can be done?