Potential memory leak with Ionide F# Extension

[gatinha96]

Version

7.29.0

Dotnet Info

.NET SDK:
Version: 9.0.200
Commit: 90e8b202f2
Workload version: 9.0.200-manifests.b4a8049f
MSBuild version: 17.13.8+cbc39bea8

Runtime Environment:
OS Name: Windows
OS Version: 10.0.26100
OS Platform: Windows
RID: win-x64
Base Path: C:\Program Files\dotnet\sdk\9.0.200\

.NET workloads installed:
There are no installed workloads to display.
Configured to use loose manifests when installing new manifests.

Host:
Version: 9.0.2
Architecture: x64
Commit: 80aa709f5d

.NET SDKs installed:
9.0.200 [C:\Program Files\dotnet\sdk]

.NET runtimes installed:
Microsoft.AspNetCore.App 9.0.2 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.NETCore.App 9.0.2 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.WindowsDesktop.App 9.0.2 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]

Other architectures found:
None

Environment variables:
Not set

global.json file:
Not found

Steps to reproduce

• Have the Ionide F# Extension enabled
• Open VS Code

Details

A .net host process originated from F# slowly climbs in memory usage until around 95% of total memory in usage.

Expected behavior

Relatively stable memory usage on all processes.

Actual behavior

Observed a .net host process climbing up in memory usage, until around 95% total memory is being consumed.

Known workarounds

Disable Ionide F# extension.

Related information

I have first posted this issue on the C# extension github, then got redirected here as the process in question originates from F#.

Logs

Ionide

[10:02:55 DEBUG] [LanguageService] FSAC (NETCORE): 'c:\Users\user.vscode\extensions\ionide.ionide-fsharp-7.29.0\bin\net9.0\fsautocomplete.dll'
[10:02:55 DEBUG] [LanguageService] F# language server options: % {
command: 'C:\Program Files\dotnet\dotnet.exe',
args: [
'c:\Users\user\.vscode\extensions\ionide.ionide-fsharp-7.29.0\bin\net9.0\fsautocomplete.dll',
'--state-directory',
'c:\Users\user\AppData\Roaming\Code\User\workspaceStorage\266cf77dd7a1ef7ddfb4ac365b9c3288\Ionide.Ionide-fsharp'
],
options: {
env: {
ALLUSERSPROFILE: 'C:\ProgramData',
APPDATA: 'C:\Users\user\AppData\Roaming',
CHROME_CRASHPAD_PIPE_NAME: '\\.\pipe\crashpad_27896_TTSPWBZDFFQUHNJU',
CommonPropertyBagPath: 'C:\Users\user\AppData\Local\Temp\csdevkit\035a05c3.json',
CommonPropertyBagWithConfigPath: 'C:\Users\user\AppData\Local\Temp\csdevkit\f510f4d3fe4d1764756173087.json',
COMPUTERNAME: 'CVIG-AM',
ComSpec: 'C:\WINDOWS\system32\cmd.exe',
CommonProgramFiles: 'C:\Program Files\Common Files',
'CommonProgramFiles(x86)': 'C:\Program Files (x86)\Common Files',
CommonProgramW6432: 'C:\Program Files\Common Files',
DADIR: 'C:\Program Files (x86)\CheckPoint\Endpoint Security\Endpoint Common',
DriverData: 'C:\Windows\System32\Drivers\DriverData',
EFC_13664_1262719628: '1',
EFC_13664_1592913036: '1',
EFC_13664_2283032206: '1',
EFC_13664_2775293581: '1',
EFC_13664_3789132940: '1',
ELECTRON_RUN_AS_NODE: '1',
FPS_BROWSER_APP_PROFILE_STRING: 'Internet Explorer',
FPS_BROWSER_USER_PROFILE_STRING: 'Default',
HOMEDRIVE: 'C:',
HOMEPATH: '\Users\user',
IGCCSVC_DB: 'AQAAANCMnd8BFdERjHoAwE/Cl+sBAAAAcACg2HckyEyCXwgdnQYbWQQAAAACAAAAAAAQZgAAAAEAACAAAACtDIVEpuGgVq2sbi6nWvpRprjqTjeoNg1wW3D6RH4EuQAAAAAOgAAAAAIAACAAAABhFXsilDPacREFjyQtLv89+IhUfh6TIl37w8n0MLDkGmAAAACkMKZnel9KAxcj1xWVqVmHYmhNcet8ge1OymZsk1LOzdX+KdYjmYz0Zb53FVbDi2F2C0wKGk6wGuwjwIbjcyQ7GkRqwBlyVxureEM9GxwEuWAVdh2FyphIf+ANkm/RrApAAAAAeWyYCWXioooV8LldseEP5gUE9Y+pE9cq3ekKzEhiRWBvcAUW3RydYBLioWhPRUAm/feYQdPHLgTAIoI6HcTY5g==',
LOCALAPPDATA: 'C:\Users\user\AppData\Local',
LOGONSERVER: '\\DC2',
NUMBER_OF_PROCESSORS: '32',
ORIGINAL_XDG_CURRENT_DESKTOP: 'undefined',
OS: 'Windows_NT',
OneDrive: 'C:\Users\user\OneDrive - Instituto CCG ZGDV',
OneDriveCommercial: 'C:\Users\user\OneDrive - Instituto CCG ZGDV',
PATHEXT: '.COM;.EXE;.BAT;.CMD;.VBS;.VBE;.JS;.JSE;.WSF;.WSH;.MSC',
PROCESSOR_ARCHITECTURE: 'AMD64',
PROCESSOR_IDENTIFIER: 'Intel64 Family 6 Model 183 Stepping 1, GenuineIntel',
PROCESSOR_LEVEL: '6',
PROCESSOR_REVISION: 'b701',
PSModulePath: 'C:\Program Files\WindowsPowerShell\Modules;C:\WINDOWS\system32\WindowsPowerShell\v1.0\Modules',
PUBLIC: 'C:\Users\Public',
Path: 'C:\WINDOWS\system32;C:\WINDOWS;C:\WINDOWS\System32\Wbem;C:\WINDOWS\System32\WindowsPowerShell\v1.0\;C:\WINDOWS\System32\OpenSSH\;C:\Program Files\NVIDIA Corporation\NVIDIA app\NvDLISR;C:\Program Files (x86)\NVIDIA Corporation\PhysX\Common;C:\Program Files (x86)\CheckPoint\Endpoint Security\Endpoint Common\bin;C:\Program Files\dotnet\;C:\Program Files\dotnet;C:\Program Files\dotnet\sdk-manifests\9.0.100;C:\Program Files\dotnet\sdk-manifests\8.0.100;C:\Users\user\AppData\Local\Microsoft\WindowsApps;C:\Users\user\AppData\Local\Programs\Microsoft VS Code\bin;C:\Users\user\.dotnet\tools;C:\Users\user\AppData\Local\Programs\Git\cmd',
ProgramData: 'C:\ProgramData',
ProgramFiles: 'C:\Program Files',
'ProgramFiles(x86)': 'C:\Program Files (x86)',
ProgramW6432: 'C:\Program Files',
SESSIONNAME: 'Console',
SystemDrive: 'C:',
SystemRoot: 'C:\WINDOWS',
TEMP: 'C:\Users\ANDREI1.MEN\AppData\Local\Temp',
TMP: 'C:\Users\ANDREI1.MEN\AppData\Local\Temp',
USERDNSDOMAIN: 'CCG.LOCAL',
USERDOMAIN: 'CCG',
USERDOMAIN_ROAMINGPROFILE: 'CCG',
USERNAME: 'user',
USERPROFILE: 'C:\Users\user',
VSCODE_CODE_CACHE_PATH: 'C:\Users\user\AppData\Roaming\Code\CachedData\bf9252a2fb45be6893dd8870c0bf37e2e1766d61',
VSCODE_CRASH_REPORTER_PROCESS_TYPE: 'extensionHost',
VSCODE_CWD: 'C:\Users\user\AppData\Local\Programs\Microsoft VS Code',
VSCODE_DOTNET_INSTALL_TOOL_ORIGINAL_HOME: 'undefined',
VSCODE_ESM_ENTRYPOINT: 'vs/workbench/api/node/extensionHostProcess',
VSCODE_HANDLES_UNCAUGHT_ERRORS: 'true',
VSCODE_IPC_HOOK: '\\.\pipe\bb357d2a-1.106.3-main-sock',
VSCODE_NLS_CONFIG: '{"userLocale":"en-us","osLocale":"en-gb","resolvedLanguage":"en","defaultMessagesFile":"C:\\Users\\user\\AppData\\Local\\Programs\\Microsoft VS Code\\resources\\app\\out\\nls.messages.json","locale":"en-us","availableLanguages":{}}',
VSCODE_PID: '27896',
ZES_ENABLE_SYSMAN: '1',
__COMPAT_LAYER: 'DetectorsAppHealth',
tvdumpflags: '8',
windir: 'C:\WINDOWS',
DOTNET_GCNoAffinitize: 0,
DOTNET_GCHeapCount: '0',
DOTNET_GCConserveMemory: 0,
DOTNET_GCServer: 1
}
}
}
[10:02:57 DEBUG] [Main] Activating features

F#

[10:02:57 DEBUG] [TestExplorer] Extension Storage c:\Users\user\AppData\Roaming\Code\User\workspaceStorage\266cf77dd7a1ef7ddfb4ac365b9c3288\Ionide.Ionide-fsharp

Checklist

• I have looked through existing issues to make sure that this bug has not been reported before
• I have provided a descriptive title for this issue
• I have made sure that that this bug is reproducible on the latest version of the package
• I have provided all the information needed to reproduce this bug as efficiently as possible
• I or my company would be willing to contribute this fix

[TheAngryByrd]

Hmm, that's interesting. I'd recommend turning on verbose logging (FSharp.verboseLogging) and see if we're reprocessing anything. If I had to guess, it generates some msbuild/sln reload constantly.

---

Additionally, since we do use Server GC, it's usually pretty greedy and F# compiler has lots of Large Object Heap allocations. I'd recommend enabling FSharp.fsac.gc.conserveMemory which lets dotnet collection LOH. I personally use 9 but even 1 is effective.

[gatinha96]

@TheAngryByrd I've enabled the verbose logging, here it is:

F#.log

I have also changed the conserve memory setting to 9 as you suggested, the problem still persists however.

As a side note, i can now confirm this problem is only related to Ionide F#, not the C# extension. (More details on the last message i sent on the C# Git)

[TheAngryByrd]

The other option is to turn off Server GC and see if it's still an issue. FSharp.fsac.gc.server. The other option to try is FSharp.fsac.gc.useDatas as that tries to blend server/workstation gc modes more dynamically.

There's unfortunately nothing that points to problems in that log. You'll have to use something like dotnet dump to see what's using up memory.

[gatinha96]

@TheAngryByrd Both options seem to make no change.
Unfortunately, I'm on a company PC and it's a bit of a hassle to get permission to install new stuff, which i can't really do now :(
Are you able to replicate the problem? Or is it just happening to me?

[TheAngryByrd]

I don't have this problem with my current work project, which is a mixed C#/F# spanning 60+ projects and with 200k+ lines of F#.

Projects can be impossibly complex. Unfortunately, unless you have a project that can be shared, it's unlikely anyone can reproduce it.

[gatinha96]

@TheAngryByrd Seems like a dead end, I'll explain what i can of my set up, hopefully it can be replicated.
My project is currently a C# Unity (version 6000.2.7f2) project, i don't use F# at all (so i can disable the extension without problem).

I had it because it comes included in the .net Extension Pack, which comes with Ionide F#, C#, Polyglot Notebooks and Jupyter (Jupyter, Jupyter Cell Tags, Jupyter Keymap, Jupiter Slide Show), and their dependencies (.net install tool).
Additionally,
Unity, which depends on C# Dev Kit;
Unity Code Snippets;
ShaderLabVSCode(Free);
Omni Shader Tools For Unity;
Live Server;
Jupyter Notebook Renderers;
Git Graph V3;
CMake and CMake Tools;