Long running encodedSemanticClassifications-full request with @discordjs/voice

[Laci0503]

Issue Type: Performance Issue

JavaScript autocomplete becomes very slow and uses a lot of cpu.
Steps to reproduce:
I am using the Discord.JS library, and the VoiceConnection object uses events which are not named with strings but objects.
For example:
(method) TypedEmitter.on<VoiceConnectionStatus.Disconnected>(event: VoiceConnectionStatus.Disconnected, listener: (oldState: VoiceConnectionState, newState: (VoiceConnectionDisconnectedOtherState & {
...;
}) | (VoiceConnectionDisconnectedWebSocketState & {
...;
})) => Awaited<...>): VoiceConnection

It seems to me that if I bind an event to this emitter, the autocomplete becomes slow.
Example:
this.voice_connection.on(VoiceConnectionStatus.Disconnected, (old_state, new_state)=>{
if(this.state=="PLAYING"){
this.pause();
}
});
However if I comment this out it stops lagging.
I reproduced this with extensions disabled.

VS Code version: Code 1.66.2 (dfd34e8260c270da74b5c2d86d61aee4b6d56977, 2022-04-11T07:46:01.075Z)
OS version: Windows_NT x64 10.0.19043
Restricted Mode: No

System Info

Item	Value
CPUs	AMD Ryzen 5 2600X Six-Core Processor (12 x 3593)
GPU Status	2d_canvas: enabled canvas_oop_rasterization: disabled_off direct_rendering_display_compositor: disabled_off_ok gpu_compositing: enabled multiple_raster_threads: enabled_on oop_rasterization: enabled opengl: enabled_on rasterization: enabled raw_draw: disabled_off_ok skia_renderer: enabled_on video_decode: enabled video_encode: enabled vulkan: disabled_off webgl: enabled webgl2: enabled
Load (avg)	undefined
Memory (System)	15.95GB (8.38GB free)
Process Argv	--crash-reporter-id 47a451dd-9d7e-42a4-85ae-b917b84d9992
Screen Reader	no
VM	0%

Process Info

CPU %	Mem MB	   PID	Process
    0	    95	 13412	code main
    0	   121	  7776	   extensionHost
    0	   703	  8776	     "C:\Program Files\Microsoft VS Code\Code.exe" --ms-enable-electron-run-as-node --max-old-space-size=3072 "c:\Program Files\Microsoft VS Code\resources\app\extensions\node_modules\typescript\lib\tsserver.js" --useInferredProjectPerProjectRoot --enableTelemetry --cancellationPipeName C:\Users\kecsk\AppData\Local\Temp\vscode-typescript\a1f96df8b23d1affac48\tscancellation-c5c1e941f078bbe6e437.tmp* --locale en --noGetErrOnBackgroundUpdate --validateDefaultNpmLocation --useNodeIpc
    0	    94	  9872	       "C:\Program Files\Microsoft VS Code\Code.exe" --ms-enable-electron-run-as-node "c:/Program Files/Microsoft VS Code/resources/app/extensions/node_modules/typescript/lib/typingsInstaller.js" --globalTypingsCacheLocation C:/Users/kecsk/AppData/Local/Microsoft/TypeScript/4.6 --enableTelemetry --typesMapLocation "c:/Program Files/Microsoft VS Code/resources/app/extensions/node_modules/typescript/lib/typesMap.json" --validateDefaultNpmLocation
    0	   121	 22200	     "C:\Program Files\Microsoft VS Code\Code.exe" --ms-enable-electron-run-as-node --max-old-space-size=3072 "c:\Program Files\Microsoft VS Code\resources\app\extensions\node_modules\typescript\lib\tsserver.js" --serverMode partialSemantic --useInferredProjectPerProjectRoot --disableAutomaticTypingAcquisition --cancellationPipeName C:\Users\kecsk\AppData\Local\Temp\vscode-typescript\a1f96df8b23d1affac48\tscancellation-4b1f8abb5201e1af6356.tmp* --locale en --noGetErrOnBackgroundUpdate --validateDefaultNpmLocation --useNodeIpc
    0	   101	 16984	   shared-process
    0	    81	 14868	     fileWatcher
    0	    76	 18272	     ptyHost
    0	    69	 14368	       C:\Windows\System32\WindowsPowerShell\v1.0\powershell.exe
    0	     6	 24380	       console-window-host (Windows internal process)
    0	   126	 19692	   gpu-process
    0	    38	 20580	   utility-network-service
    0	    88	 21564	   issue-reporter
    0	    26	 22972	   crashpad-handler
    0	   221	 23236	   window (audio_cache.ts - bot - Visual Studio Code)

Workspace Info

|  Window (audio_cache.ts - bot - Visual Studio Code)
|    Folder (bot): 48 files
|      File types: ts(20) json(3) opus(2) dockerignore(1) gitignore(1) m4a(1)
|      Conf files: dockerfile(1) package.json(1);

Extensions: none

A/B Experiments

vsliv368:30146709
vsreu685:30147344
python383:30185418
vspor879:30202332
vspor708:30202333
vspor363:30204092
vswsl492:30256859
pythonvspyl392:30443607
pythontb:30283811
pythonptprofiler:30281270
vshan820:30294714
vstes263:30335439
vscoreces:30445986
pythondataviewer:30285071
vscod805cf:30301675
pythonvspyt200:30340761
binariesv615:30325510
bridge0708:30335490
bridge0723:30353136
vsaa593cf:30376535
vsc1dst:30438360
pythonvs932:30410667
wslgetstarted:30449410
pythonvsnew555:30457759
vscscmwlcmt:30465135
cppdebug:30475216

[mjbvz]

Does this reproduce in the latest VS Code insiders build with all extensions disabled?

[Laci0503]

Yes, I am able to reproduce it in the latest insiders build as well.

[Laci0503]

This is the exact piece of code that makes it lag. However having only one this.voice_connection.on() part makes it lag just as much.
this.voice_connection is a VoiceConnection object from the @discordjs/voice library.
These are the npm packages installed:
"dependencies": {
"@discordjs/voice": "^0.9.0",
"discord.js": "^13.6.0",
"ffmpeg-static": "^4.4.1",
"googleapis": "^100.0.0",
"prism-media": "^1.3.2",
"sodium": "^3.0.2",
"tinyduration": "^3.2.2",
"ts-node": "^10.7.0",
"typescript": "^4.6.3"
}

this.voice_connection.on(VoiceConnectionStatus.Disconnected, (old_state, new_state)=>{
    if(this.state=="PLAYING"){
        this.pause();
    }
});
this.voice_connection.on(VoiceConnectionStatus.Ready, (new_state, old_state)=>{
    if(this.state=="PAUSED"){
        this.resume();
    }
});
this.voice_connection.on(VoiceConnectionStatus.Connecting, (old_state, new_state)=>{
    if(this.state=="PLAYING"){
        this.pause();
    }
});
this.voice_connection.on(VoiceConnectionStatus.Signalling, (old_state, new_state)=>{
    if(this.state=="PLAYING"){
        this.pause();
    }
});
this.voice_connection.on(VoiceConnectionStatus.Destroyed, (old_state, new_state)=>{
    if(this.state=="PLAYING" || this.state=="PAUSED"){
        this.stop();
    }
});

EDIT: The lag stops if there are 0 or 1 arguments in the handler.
For example:
this.voice_state.on(VoiceConnectionStatus.Disconnected, ()=>{})
or this.voice_state.on(VoiceConnectionStatus.Disconnected, (new_state)=>{})

[mjbvz]

Can you please share a small, self contained project that demonstrates the issue?

[Laci0503]

I could not really find out why it happens with this library, but here is an example of the problem: https://github.com/Laci0503/vscode-lag-issue-test-project.git
I have tried to recreate it without the @discordjs/voice library but there must be something in its types of source which makes it lag.

[mjbvz]

Thanks @Laci0503

With the project, I see encodedSemanticClassifications-full taking a long time

Info 239  [20:51:09.308] request:
    {
      "seq": 74,
      "type": "request",
      "command": "encodedSemanticClassifications-full",
      "arguments": {
        "file": "/workspaces/vscode-lag-issue-test-project/index.ts",
        "start": 0,
        "length": 162,
        "format": "2020"
      }
    }
Perf 240  [20:51:12.988] 74::encodedSemanticClassifications-full: elapsed time (in milliseconds) 3680.1233

Moving for TS for investigation

[Laci0503]

Thanks for your help.