Visual Studio constantly consumes ~50 - 90% CPU after opening a large project

[davkean]

After fixing: #2383 which makes VS much more responsive - but Visual Studio still consumes 50% - 90% CPU after opening a large project.

1. Apply the fix from [Regression] Visual Studio becomes unresponsive for a long time after opening a large project trying to populate Dependency node #2383
2. git clone https://github.com/aarnott/pinvoke
3. cd pinvoke
4. git checkout c5642c29ddd
5. src\pinvoke.sln

Expected: After init has finished and we've processed design-time builds for CPU to be around or close to 0%.
Actual: CPU is constantly pegged for 50% - 90%, looking at dumps lots of dependency node code still runnning.

[davkean]

I suspect this only occurs for cross-targeting projects.

[abpiskunov]

When you say DT builds are processed - what did you mean? Dependencies are processing them when new data comes, if code is still around DT builds are not processed yet.. Or processed and sent tree update requests which could be pending/in progress by tree provider.

[davkean]

I don't know yet as I haven't dug into the details - but if I leave the project for 20 minutes we're still consuming lots of CPU.

[davkean]

I'm seeing lots of CPU usage also in Roslyn.sln.

[davkean]

I'm seeing part of the problem - looks like Test Window is doing a IsDocumentInProject on all projects - which is walking into every single dependency node:

 	System.dll!System.Uri.CreateUriInfo(System.Uri.Flags cF)	Unknown
 	System.dll!System.Uri.EnsureUriInfo()	Unknown
 	System.dll!System.Uri.ParseRemaining()	Unknown
 	System.dll!System.Uri.GetLocalPath()	Unknown
 	System.dll!System.Uri.LocalPath.get()	Unknown
 	Microsoft.VisualStudio.ProjectSystem.Implementation.dll!Microsoft.VisualStudio.ProjectSystem.UnconfiguredProjectImpl.Microsoft.VisualStudio.ProjectSystem.UnconfiguredProjectInternal.MakeRooted(string path) Line 1160	C#
 	Microsoft.VisualStudio.ProjectSystem.dll!Microsoft.VisualStudio.ProjectSystem.PathHelper.MakeRooted(Microsoft.VisualStudio.ProjectSystem.UnconfiguredProject unconfiguredProject, string path) Line 373	C#
 	Microsoft.VisualStudio.ProjectSystem.Implementation.dll!Microsoft.VisualStudio.ProjectSystem.Designers.UnattachedProjectItemTreeNode.FilePath.get() Line 75	C#
 	Microsoft.VisualStudio.ProjectSystem.Implementation.dll!Microsoft.VisualStudio.ProjectSystem.Designers.ProjectTree.FilePath.get() Line 108	C#
 	Microsoft.VisualStudio.ProjectSystem.Managed.VS.dll!Microsoft.VisualStudio.ProjectSystem.VS.IProjectTreeExtensions.FindNodeByPath.AnonymousMethod__2_0(Microsoft.VisualStudio.ProjectSystem.IProjectTree child) Line 77	C#
 	Microsoft.VisualStudio.ProjectSystem.Managed.VS.dll!Microsoft.VisualStudio.ProjectSystem.VS.IProjectTreeExtensions.FindNodeHelper.AnonymousMethod__0(Microsoft.VisualStudio.ProjectSystem.IProjectTree child) Line 98	C#
 	System.Core.dll!System.Linq.Enumerable.FirstOrDefault<Microsoft.VisualStudio.ProjectSystem.IProjectTree>(System.Collections.Generic.IEnumerable<Microsoft.VisualStudio.ProjectSystem.IProjectTree> source, System.Func<Microsoft.VisualStudio.ProjectSystem.IProjectTree, bool> predicate)	Unknown
>	Microsoft.VisualStudio.ProjectSystem.Managed.VS.dll!Microsoft.VisualStudio.ProjectSystem.VS.IProjectTreeExtensions.FindNodeHelper(Microsoft.VisualStudio.ProjectSystem.IProjectTree tree, string itemToFind, System.Func<Microsoft.VisualStudio.ProjectSystem.IProjectTree, string> childPropertyFunction) Line 97	C#
 	Microsoft.VisualStudio.ProjectSystem.Managed.VS.dll!Microsoft.VisualStudio.ProjectSystem.VS.IProjectTreeExtensions.FindNodeByPath(Microsoft.VisualStudio.ProjectSystem.IProjectTree tree, string itemPath) Line 77	C#
 	Microsoft.VisualStudio.ProjectSystem.Managed.VS.dll!Microsoft.VisualStudio.ProjectSystem.VS.Tree.Dependencies.GroupedByTargetTreeViewProvider.FindByPathInternal(Microsoft.VisualStudio.ProjectSystem.IProjectTree root, string path) Line 170	C#
 	Microsoft.VisualStudio.ProjectSystem.Managed.VS.dll!Microsoft.VisualStudio.ProjectSystem.VS.Tree.Dependencies.GroupedByTargetTreeViewProvider.FindByPath(Microsoft.VisualStudio.ProjectSystem.IProjectTree root, string path) Line 153	C#
 	Microsoft.VisualStudio.ProjectSystem.Managed.VS.dll!Microsoft.VisualStudio.ProjectSystem.VS.Tree.Dependencies.DependenciesProjectTreeProvider.FindByPath(Microsoft.VisualStudio.ProjectSystem.IProjectTree root, string path) Line 291	C#
 	Microsoft.VisualStudio.ProjectSystem.Implementation.dll!Microsoft.VisualStudio.ProjectSystem.Designers.PhysicalProjectTreeProvider.FindByPath(Microsoft.VisualStudio.ProjectSystem.IProjectTree root, string path, System.StringComparison comparisonType, bool definitelyNotOutsideProjectDirectory) Line 2109	C#
 	Microsoft.VisualStudio.ProjectSystem.Implementation.dll!Microsoft.VisualStudio.ProjectSystem.Designers.PhysicalProjectTreeProvider.FindByPath(Microsoft.VisualStudio.ProjectSystem.IProjectTree root, string path) Line 267	C#
 	Microsoft.VisualStudio.ProjectSystem.VS.Implementation.dll!Microsoft.VisualStudio.ProjectSystem.VS.Implementation.Package.ProjectNode.StandardIsDocumentInProjectHandler.IsDocumentInProjectAsync(string documentMoniker) Line 6345	C#
 	Microsoft.VisualStudio.ProjectSystem.VS.Implementation.dll!Microsoft.VisualStudio.ProjectSystem.VS.Implementation.Package.ProjectNode.IsDocumentInProjectInternal.AnonymousMethod__0() Line 5772	C#
 	Microsoft.VisualStudio.Threading.dll!Microsoft.VisualStudio.Threading.JoinableTaskFactory.ExecuteJob<Microsoft.VisualStudio.Threading.EmptyStruct>(System.Func<System.Threading.Tasks.Task> asyncMethod, Microsoft.VisualStudio.Threading.JoinableTask job)	Unknown
 	Microsoft.VisualStudio.Threading.dll!Microsoft.VisualStudio.Threading.JoinableTaskFactory.RunAsync(System.Func<System.Threading.Tasks.Task> asyncMethod, bool synchronouslyBlocking, Microsoft.VisualStudio.Threading.JoinableTaskCreationOptions creationOptions, System.Delegate entrypointOverride)	Unknown
 	Microsoft.VisualStudio.ProjectSystem.Implementation.dll!Microsoft.VisualStudio.ProjectSystem.ProjectMultiThreadedService.ExecuteSynchronously(System.Func<System.Threading.Tasks.Task> asyncAction) Line 127	C#
 	Microsoft.VisualStudio.ProjectSystem.VS.Implementation.dll!Microsoft.VisualStudio.ProjectSystem.VS.Implementation.Package.ProjectNode.HrInvoke.AnonymousMethod__0() Line 3750	C#
 	Microsoft.VisualStudio.ProjectSystem.VS.dll!Microsoft.VisualStudio.ProjectSystem.VS.HResult.Invoke.AnonymousMethod__0() Line 294	C#
 	Microsoft.VisualStudio.ProjectSystem.VS.dll!Microsoft.VisualStudio.ProjectSystem.VS.HResult.Invoke(System.Func<Microsoft.VisualStudio.ProjectSystem.VS.HResult> action, System.IServiceProvider vsShellServiceProvider, Microsoft.VisualStudio.ProjectSystem.IProjectFaultHandlerService projectFaultHandlerService, Microsoft.VisualStudio.ProjectSystem.UnconfiguredProject project) Line 313	C#
 	Microsoft.VisualStudio.ProjectSystem.VS.Implementation.dll!Microsoft.VisualStudio.ProjectSystem.VS.Implementation.Package.ProjectNode.HrInvoke(System.Func<System.Threading.Tasks.Task> asyncAction, bool registerProjectFaultHandlerService) Line 3746	C#
 	Microsoft.VisualStudio.ProjectSystem.VS.Implementation.dll!Microsoft.VisualStudio.ProjectSystem.VS.Implementation.Package.ProjectNode.IsDocumentInProjectInternal(string mkDoc, bool useDocumentPriority2, out int found, out int pri, out uint itemId) Line 5769	C#
 	Microsoft.VisualStudio.ProjectSystem.VS.Implementation.dll!Microsoft.VisualStudio.ProjectSystem.VS.Implementation.Package.ProjectNode.IsDocumentInProject(string mkDoc, out int found, Microsoft.VisualStudio.Shell.Interop.VSDOCUMENTPRIORITY[] pri, out uint itemId) Line 1885	C#
 	Microsoft.VisualStudio.ProjectSystem.VS.Implementation.dll!Microsoft.VisualStudio.ProjectSystem.VS.Implementation.Package.ProjectNodeWrapper.IsDocumentInProject(string pszMkDocument, out int pfFound, Microsoft.VisualStudio.Shell.Interop.VSDOCUMENTPRIORITY[] pdwPriority, out uint pitemid) Line 140	C#

I've got a trace, and trying to interpret it.

[davkean]

For a 10 second period I'm seeing 400 GCs (362 Gen0, 38 Gen1), that can't be normal...

[davkean]

The test delay is something else, and being tracked by another bug.

I spent more time looking into - it looks like we're constantly getting called back with "project changes" in CrossTargetRuleSubscriberBase.OnProjectChangedAsync.

[davkean]

Looks like for each ConfiguredProject, we have 6 design-time subscription links, and 6 evaluation subscriptions link, that probably doesn't help.

[davkean]

Yeah, that 6 subscriptions should be halved because we're sync'ing to the catalog source, but basically, looks like we're adding too many subscriptions - now to figure that out.

[davkean]

The subscriptions were a red herring, they are expected, as we subscribe to 2 things per configuration.

The real issue is that we're continuously resetting subscriptions. The underlying reason is because we're expecting a user written value ("TargetFramework") to be canonical, from our guidelines:

• DO NOT parse or attempt to reason about the values of properties that make up the dimensions for a project configuration; $(Configuration), $(Platform) and $(TargetFramework), and their plural counterparts; $(Configurations), $(Platforms) and $(TargetFrameworks).
  These properties are user "aliases" and should only be used for conditions, display and grouping purposes. Instead, the project system should be using their canonical equivalents; $(PlatformTarget) instead of $(Platform), and $(TargetFrameworkMoniker) instead of $(TargetFramework).

The end result is that we're comparing:

portable-net40+win8+wpa81 

against:

portable-net4+win8+wpa81 

And this fails.

[srivatsn]

Fixed by #2526

[grahamehorner]

I have VS 2017.3 Preview 3 showing the same symptoms, but I wouldn't consider it the big a large project; 1 project with approx. 30 bower packages ? very little in the way of C# code.