F# on Visual Studio 2022 very slow

Question

This only applies to Visual Studio 2022. I had uninstalled VS2019 and Preview where F# worked absolutely fine (F# 5.0). I am using VS2022 to use F# 6.0 and do not want to go back to F# 5.0.

The issue is specific to F#. I also use C# and I have no issues running the latest C# under VS2022.

There are near continual DevEnv processes running consuming anywhere from 1 to 4 of my CPU's 4 Hyperthreads. I have switched off all experimental options I can find in F# settings.

Sometimes there are 2 or more background processes running, sometimes paused and sometimes none - there appears to be no correlation between this and the background CPU consumption

Sometimes I have a pop up Dialog about waiting to complete an editor process or a compile process.

When devenev.exe is consuming CPU cycles under the properties I see there is always one clr.dllCoUnInitializeEE+0x6790 that is the culprit. I though this was meant to be a short-lived process? Sometimes there are two or three of these consuming most of a HyperThread (There are identical others but with very low or no CPU consumption). The stack on the guilty thread is as follows:

1, Microsoft.FSharp.Collections.SeqModule+Zip@633[[System.__Canon, mscorlib],[System.__Canon, mscorlib]].Invoke(System.__Canon, System.__Canon) + 0x50 <-- FSharp.Core.ni.dll+0x83f430
2, Microsoft.FSharp.Collections.Internal+IEnumerator+map2@103[[System.__Canon, mscorlib],[System.__Canon, mscorlib],[System.__Canon, mscorlib]].DoMoveNext(System.__Canon ByRef) + 0xca <-- FSharp.Core.ni.dll+0x8476ba
3, Microsoft.FSharp.Collections.Internal+IEnumerator+MapEnumerator`1[[System.__Canon, mscorlib]].System.Collections.IEnumerator.MoveNext() + 0x40 <-- FSharp.Core.ni.dll+0x847270
4, Microsoft.FSharp.Collections.SeqModule.ForAll[[System.__Canon, mscorlib]](Microsoft.FSharp.Core.FSharpFunc`2<System.__Canon,Boolean>, System.Collections.Generic.IEnumerable`1<System.__Canon>) + 0x76 <-- FSharp.Core.ni.dll+0x753466
5, FSharp.Compiler.Symbols.SymbolHelpers+ItemDisplayPartialEquality@485.System.Collections.Generic.IEqualityComparer<FSharp.Compiler.NameResolution.Item>.Equals(Item, Item) + 0x24 <-- FSharp.Compiler.Service.ni.dll+0x2900294
6, System.Collections.Generic.Dictionary`2[[System.__Canon, mscorlib],[System.__Canon, mscorlib]].Insert(System.__Canon, System.__Canon, Boolean) + 0x200 <-- mscorlib.ni.dll+0x57bea0
7, Internal.Utilities.Library.IPartialEqualityComparer+partialDistinctBy@1001[[System.__Canon, mscorlib]].Invoke(System.__Canon) + 0xb0 <-- FSharp.Compiler.Service.ni.dll+0x2bc9540
8, Microsoft.FSharp.Primitives.Basics.List.filterToFreshConsTail[[System.__Canon, mscorlib]](Microsoft.FSharp.Collections.FSharpList`1<System.__Canon>, Microsoft.FSharp.Core.FSharpFunc`2<System.__Canon,Boolean>, Microsoft.FSharp.Collections.FSharpList`1<System.__Canon>) + 0x4e <-- FSharp.Core.ni.dll+0x76060e
9, Microsoft.FSharp.Primitives.Basics.List.filter[[System.__Canon, mscorlib]](Microsoft.FSharp.Core.FSharpFunc`2<System.__Canon,Boolean>, Microsoft.FSharp.Collections.FSharpList`1<System.__Canon>) + 0xe7 <-- FSharp.Core.ni.dll+0x760747
10, FSharp.Compiler.EditorServices.DeclarationListInfo.Create(InfoReader, AccessorDomain, FSharp.Compiler.Text.Range, DisplayEnv, Microsoft.FSharp.Core.FSharpFunc`2<Item,FSharp.Compiler.Symbols.FSharpAccessibility>, Microsoft.FSharp.Collections.FSharpList`1<FSharp.Compiler.EditorServices.CompletionItem>, Microsoft.FSharp.Core.FSharpOption`1<System.String[]>, Boolean) + 0x2a0 <-- FSharp.Compiler.Service.ni.dll+0x274a830
11, <StartupCode$FSharp-Compiler-Service>.$FSharpCheckerResults+GetDeclarations@1088.Invoke(Microsoft.FSharp.Core.Unit) + 0x2a0 <-- FSharp.Compiler.Service.ni.dll+0x289c0b0
12, FSharp.Compiler.Diagnostics.ErrorScope.Protect[[System.__Canon, mscorlib]](FSharp.Compiler.Text.Range, Microsoft.FSharp.Core.FSharpFunc`2<Microsoft.FSharp.Core.Unit,System.__Canon>, Microsoft.FSharp.Core.FSharpFunc`2<System.String,System.__Canon>) + 0x58 <-- FSharp.Compiler.Service.ni.dll+0x24a7d28
13, FSharp.Compiler.CodeAnalysis.TypeCheckInfo.GetDeclarations(Microsoft.FSharp.Core.FSharpOption`1<FSharp.Compiler.CodeAnalysis.FSharpParseFileResults>, Int32, System.String, FSharp.Compiler.EditorServices.PartialLongName, Microsoft.FSharp.Core.FSharpFunc`2<Microsoft.FSharp.Core.Unit,Microsoft.FSharp.Collections.FSharpList`1<FSharp.Compiler.EditorServices.AssemblySymbol>>) + 0x101 <-- FSharp.Compiler.Service.ni.dll+0x27b3831
14, <StartupCode$FSharp-Compiler-Service>.$FSharpCheckerResults+GetDeclarationListInfo@1953-1.Invoke(FSharp.Compiler.CodeAnalysis.TypeCheckInfo) + 0x31 <-- FSharp.Compiler.Service.ni.dll+0x28a33d1
15, <StartupCode$FSharp-Editor>.$CompletionProvider+ProvideCompletionsAsyncAux@110-6.Invoke(Microsoft.CodeAnalysis.Text.SourceText) + 0x143 <-- 0x7ffdb4beacd3
16, Microsoft.FSharp.Control.AsyncPrimitives.CallThenInvokeNoHijackCheck[[System.__Canon, mscorlib],[System.__Canon, mscorlib]](Microsoft.FSharp.Control.AsyncActivation`1<System.__Canon>, System.__Canon, Microsoft.FSharp.Core.FSharpFunc`2<System.__Canon,Microsoft.FSharp.Control.FSharpAsync`1<System.__Canon>>) + 0x3e <-- FSharp.Core.ni.dll+0x7c756e
17, clr.dll+0x42b6
18, Microsoft.FSharp.Control.Trampoline.Execute(Microsoft.FSharp.Core.FSharpFunc`2<Microsoft.FSharp.Core.Unit,Microsoft.FSharp.Control.AsyncReturn>) + 0x60 <-- FSharp.Core.ni.dll+0x7c5420
19, <StartupCode$FSharp-Core>.$Async+AwaitWaitHandle@1661-3.Invoke(System.Object, Boolean) + 0xc5 <-- FSharp.Core.ni.dll+0x824265
20, System.Threading.ExecutionContext.RunInternal(System.Threading.ExecutionContext, System.Threading.ContextCallback, System.Object, Boolean) + 0x172 <-- mscorlib.ni.dll+0x58df12
21, System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext, System.Threading.ContextCallback, System.Object, Boolean) + 0x15 <-- mscorlib.ni.dll+0x58dd95
22, System.Threading._ThreadPoolWaitOrTimerCallback.PerformWaitOrTimerCallback(System.Object, Boolean) + 0xed <-- mscorlib.ni.dll+0xf3676d
23, clr.dll!CoUninitializeEE+0x1b73
24, clr.dll!CoUninitializeEE+0x1a88
25, clr.dll!DllRegisterServerInternal+0x19f43
26, clr.dll!TranslateSecurityAttributes+0x298b3
27, clr.dll!CoUninitializeEE+0x2f30
28, clr.dll!CoUninitializeEE+0x2ea3
29, clr.dll!CoUninitializeEE+0x2de2
30, clr.dll!CoUninitializeEE+0x2fc7
31, clr.dll!TranslateSecurityAttributes+0x296ff
32, clr.dll!ReOpenMetaDataWithMemoryEx+0x1252
33, clr.dll!ReOpenMetaDataWithMemoryEx+0x4090
34, clr.dll!GetMetaDataPublicInterfaceFromInternal+0x1bde5
35, clr.dll!CoUninitializeEE+0x6815
36, kernel32.dll!BaseThreadInitThunk+0x14
37, ntdll.dll!RtlUserThreadStart+0x21

I have reinstalled VS2022 just for windows C# and F# projects and nothing else.

Hopefully this is enough information to provide clues as to what is going on.

Update

See comments for my further efforts at tidyups and have what I think are needed Framework 4.6 and 4.7 dot net dlls/runtimes and only one dot net core which I think is 6.0 but is listed as Microsoft .NET Core SDK - 2.1.202(x64) - if that is the issue.

The issue still seems to be CoUninitialize which should be a short-lived thread to unload COM objects - see https://docs.microsoft.com/en-us/windows/win32/api/combaseapi/nf-combaseapi-couninitialize . What bit of F# is using Com Objects that are failing to unload, as this does not happen when editing/compiling C# projects?

Update 2

I re-installed VS2022 again with minimal dot net libraries IIRC it needed 4.6 and 4.7 Framework for some C# and F# to be installed. Now everything is back whilst I have done nothing else including no auto-updates etc. Here is the latest dump from dotnet --info :

PS ..> dotnet --info
.NET SDK (reflecting any global.json):
 Version:   6.0.100
 Commit:    9e8b04bbff

Runtime Environment:
 OS Name:     Windows
 OS Version:  10.0.18363
 OS Platform: Windows
 RID:         win10-x64
 Base Path:   C:\Program Files\dotnet\sdk\6.0.100\

Host (useful for support):
  Version: 6.0.0
  Commit:  4822e3c3aa

.NET SDKs installed:
  2.1.202 [C:\Program Files\dotnet\sdk]
  3.1.413 [C:\Program Files\dotnet\sdk]
  5.0.302 [C:\Program Files\dotnet\sdk]
  5.0.403 [C:\Program Files\dotnet\sdk]
  6.0.100 [C:\Program Files\dotnet\sdk]

.NET runtimes installed:
  Microsoft.AspNetCore.All 2.1.28 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.All 2.1.29 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.All 2.1.30 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.App 2.1.28 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 2.1.29 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 2.1.30 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 3.1.17 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 3.1.18 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 3.1.19 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 3.1.21 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 5.0.1 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 5.0.4 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 5.0.8 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 5.0.9 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 5.0.10 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 5.0.12 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 6.0.0 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.NETCore.App 2.0.9 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.1.28 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.1.29 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.1.30 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 3.1.17 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 3.1.18 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 3.1.19 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 3.1.21 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 5.0.1 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 5.0.4 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 5.0.8 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 5.0.9 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 5.0.12 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 6.0.0 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.WindowsDesktop.App 3.1.17 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 3.1.18 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 3.1.19 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 5.0.1 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 5.0.4 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 5.0.8 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 5.0.9 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 5.0.12 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 6.0.0 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]

After using dotnet-core-uninstall again, some skds/runtimes magically re-appeared here it the current output:

    PS C:\WINDOWS\system32> dotnet-core-uninstall list

This tool cannot uninstall versions of the runtime or SDK that are 
    - SDKs installed using Visual Studio 2019 Update 3 or later.
    - SDKs and runtimes installed via zip/scripts.
    - Runtimes installed with SDKs (these should be removed by removing that SDK).
The versions that can be uninstalled with this tool are:

.NET Core SDKs:
  5.0.403  x64    [Used by Visual Studio. Specify individually or use --force to remove]
  2.1.202  x64    [Used by Visual Studio. Specify individually or use --force to remove]

.NET Core Runtimes:

ASP.NET Core Runtimes:
  5.0.12  x86
  5.0.10  x64
  3.1.21  x64
  2.1.30  x64

.NET Core Runtime & Hosting Bundles:

Answer 1

Please report to Microsoft either using the people app in windows or the visual studio installer.

for now, there is only one option: use visual studio 2019. or try finding alternatives. there should be somewhere around the net

I suggest using Rider IDE instead(until the devs fix the bug): Download Rider IDE

I'm not really trying to advertise here, just suggesting an IDE Too compile and run you rprogram.

Answer 2

I do not know why but I ran Chris Titus' Windows debloat and did general cleanups eg for StartUp, Services and removing old/unused programs and something in that fixed the issue. Not really an answer for anyone else but maybe this can help someone too.