Extension causes high CPU usage

[lonelyteapot]

Type: Performance Issue

When I type quickly in Python files, it starts to noticeably lag. CPU usage spikes to 100%, the causing process being extensionHost.

It happens with an empty file, in a fresh project with default configuration.

Maybe the issue is that Ruff gets called too frequently (after every character input) and either my CPU or my HDD(?) can't handle the load.

Maybe an option to limit this frequency can be added?

---

Extension version: 2023.4.0
VS Code version: Code 1.74.3 (97dec172d3256f8ca4bfb2143f3f76b503ca0534, 2023-01-09T16:59:02.252Z)
OS version: Windows_NT x64 10.0.22621
Modes:
Sandboxed: No

System Info

Item	Value
CPUs	Intel(R) Core(TM) i5-4690 CPU @ 3.50GHz (4 x 3500)
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 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 webgpu: disabled_off
Load (avg)	undefined
Memory (System)	11.90GB (2.28GB free)
Process Argv	--open-url --crash-reporter-id 53a40992-7e18-460e-913a-446086054188 -- vscode:extension/VisualStudioExptTeam.vscodeintellicode
Screen Reader	no
VM	0%

Process Info

CPU %	Mem MB	   PID	Process
    2	   144	 11000	code main
    7	   119	  2988	   shared-process
    0	    80	  7012	     ptyHost
    0	    66	  1692	       C:\WINDOWS\System32\WindowsPowerShell\v1.0\powershell.exe -noexit -command "try { . \"c:\Users\lonelyteapot\AppData\Local\Programs\Microsoft VS Code\resources\app\out\vs\workbench\contrib\terminal\browser\media\shellIntegration.ps1\" } catch {}"
    0	     6	  5348	       console-window-host (Windows internal process)
    0	     6	  5656	       console-window-host (Windows internal process)
    0	    62	 11044	       C:\WINDOWS\System32\WindowsPowerShell\v1.0\powershell.exe -noexit -command "try { . \"c:\Users\lonelyteapot\AppData\Local\Programs\Microsoft VS Code\resources\app\out\vs\workbench\contrib\terminal\browser\media\shellIntegration.ps1\" } catch {}"
    0	    96	 17468	     fileWatcher
    0	    42	  5208	   utility-network-service
    0	    26	  8784	   crashpad-handler
    2	   134	  9328	   gpu-process
    0	   102	 13112	   process-explorer
    0	     6	 15100	   "C:\Program Files\Google\Drive File Stream\68.0.2.0\crashpad_handler.exe" --database=C:\Users\lonelyteapot\AppData\Local\Google\DriveFS\Crashpad --url=https://clients2.google.com/cr/report --annotation=application=Code.exe --annotation=prod=DriveFS --annotation=ver=68.0.2.0 --initial-client-data=0x1074,0x15f4,0x15f8,0x15f0,0x15fc,0x7ffbdc5357f0,0x7ffbdc535800,0x7ffbdc535810
    0	   557	 16804	   extensionHost
    0	     3	   508	     d:\Development\lonelyteapot\Python\Transit-at-Hand-Backend\.venv\Scripts\python.exe c:\Users\lonelyteapot\.vscode\extensions\ms-python.isort-2022.9.13271012\bundled\tool\server.py
    0	     6	 10460	       console-window-host (Windows internal process)
    0	    27	 16572	       "G:\Devkits\Python311\python.exe" c:\Users\lonelyteapot\.vscode\extensions\ms-python.isort-2022.9.13271012\bundled\tool\server.py
    0	     3	   676	     d:\Development\lonelyteapot\Python\Transit-at-Hand-Backend\.venv\Scripts\python.exe c:\Users\lonelyteapot\.vscode\extensions\ms-python.black-formatter-2022.6.0\bundled\tool\server.py
    0	    24	  2560	       "G:\Devkits\Python311\python.exe" c:\Users\lonelyteapot\.vscode\extensions\ms-python.black-formatter-2022.6.0\bundled\tool\server.py
    0	     6	  5124	       console-window-host (Windows internal process)
    0	    87	  8728	     "C:\Users\lonelyteapot\AppData\Local\Programs\Microsoft VS Code\Code.exe" --ms-enable-electron-run-as-node c:\Users\lonelyteapot\.vscode\extensions\visualstudioexptteam.intellicode-api-usage-examples-0.2.6\dist\server\server.js --node-ipc --clientProcessId=16804
    0	   109	 12356	     "C:\Users\lonelyteapot\AppData\Local\Programs\Microsoft VS Code\Code.exe" --ms-enable-electron-run-as-node c:\Users\lonelyteapot\.vscode\extensions\vue.volar-1.0.24-win32-x64\server.js --node-ipc --clientProcessId=16804
    0	   107	 13048	     "C:\Users\lonelyteapot\AppData\Local\Programs\Microsoft VS Code\Code.exe" --ms-enable-electron-run-as-node c:\Users\lonelyteapot\.vscode\extensions\vue.volar-1.0.24-win32-x64\server.js --node-ipc --clientProcessId=16804
    0	     3	 17008	     d:\Development\lonelyteapot\Python\Transit-at-Hand-Backend\.venv\Scripts\python.exe c:\Users\lonelyteapot\.vscode\extensions\charliermarsh.ruff-2023.4.0-win32-x64\bundled\tool\server.py
    0	    41	  8080	       "G:\Devkits\Python311\python.exe" c:\Users\lonelyteapot\.vscode\extensions\charliermarsh.ruff-2023.4.0-win32-x64\bundled\tool\server.py
    0	    10	 10904	       console-window-host (Windows internal process)
    0	    85	 17932	     "C:\Users\lonelyteapot\AppData\Local\Programs\Microsoft VS Code\Code.exe" --ms-enable-electron-run-as-node c:\Users\lonelyteapot\.vscode\extensions\bungcip.better-toml-0.3.2\node_modules\vscode-languageclient\lib\utils\electronForkStart c:\Users\lonelyteapot\.vscode\extensions\bungcip.better-toml-0.3.2\out\server\tomlServerMain.js --node-ipc
    0	   258	 18760	     "C:\Users\lonelyteapot\AppData\Local\Programs\Microsoft VS Code\Code.exe" --ms-enable-electron-run-as-node c:\Users\lonelyteapot\.vscode\extensions\ms-python.vscode-pylance-2023.1.21\dist\server.bundle.js --cancellationReceive=file:1c85c832ff92a9af06e7f9426a8a31ed909c07f6ef --node-ipc --clientProcessId=16804
    0	    80	 19088	     "C:\Users\lonelyteapot\AppData\Local\Programs\Microsoft VS Code\Code.exe" --ms-enable-electron-run-as-node c:\Users\lonelyteapot\.vscode\extensions\stylelint.vscode-stylelint-1.2.3\dist\start-server.js --stdio --clientProcessId=16804
    0	   304	 17012	   window (● __init__.py - Transit-at-Hand-Backend - Visual Studio Code)
    1	    98	 18840	   issue-reporter
    0	   567	 18880	   extensionHost
    0	     3	  2408	     d:\Development\lonelyteapot\Python\Transit-at-Hand-Backend\.venv\Scripts\python.exe c:\Users\lonelyteapot\.vscode\extensions\ms-python.isort-2022.9.13271012\bundled\tool\server.py
    0	    11	 17720	       console-window-host (Windows internal process)
    0	    35	 19000	       "G:\Devkits\Python311\python.exe" c:\Users\lonelyteapot\.vscode\extensions\ms-python.isort-2022.9.13271012\bundled\tool\server.py
    0	    91	  4256	     "C:\Users\lonelyteapot\AppData\Local\Programs\Microsoft VS Code\Code.exe" --ms-enable-electron-run-as-node c:\Users\lonelyteapot\.vscode\extensions\stylelint.vscode-stylelint-1.2.3\dist\start-server.js --stdio --clientProcessId=18880
    0	    90	  4852	     "C:\Users\lonelyteapot\AppData\Local\Programs\Microsoft VS Code\Code.exe" --ms-enable-electron-run-as-node "c:\Users\lonelyteapot\AppData\Local\Programs\Microsoft VS Code\resources\app\extensions\json-language-features\server\dist\node\jsonServerMain" --node-ipc --clientProcessId=18880
    0	   117	  5204	     "C:\Users\lonelyteapot\AppData\Local\Programs\Microsoft VS Code\Code.exe" --ms-enable-electron-run-as-node c:\Users\lonelyteapot\.vscode\extensions\visualstudioexptteam.intellicode-api-usage-examples-0.2.6\dist\server\server.js --node-ipc --clientProcessId=18880
    0	   124	 11768	     "C:\Users\lonelyteapot\AppData\Local\Programs\Microsoft VS Code\Code.exe" --ms-enable-electron-run-as-node c:\Users\lonelyteapot\.vscode\extensions\vue.volar-1.0.24-win32-x64\server.js --node-ipc --clientProcessId=18880
    0	     3	 16544	     d:\Development\lonelyteapot\Python\Transit-at-Hand-Backend\.venv\Scripts\python.exe c:\Users\lonelyteapot\.vscode\extensions\charliermarsh.ruff-2023.4.0-win32-x64\bundled\tool\server.py
    0	    10	  5772	       console-window-host (Windows internal process)
    0	    42	 15476	       "G:\Devkits\Python311\python.exe" c:\Users\lonelyteapot\.vscode\extensions\charliermarsh.ruff-2023.4.0-win32-x64\bundled\tool\server.py
    0	     3	 16860	     d:\Development\lonelyteapot\Python\Transit-at-Hand-Backend\.venv\Scripts\python.exe c:\Users\lonelyteapot\.vscode\extensions\ms-python.black-formatter-2022.6.0\bundled\tool\server.py
    0	    37	  8916	       "G:\Devkits\Python311\python.exe" c:\Users\lonelyteapot\.vscode\extensions\ms-python.black-formatter-2022.6.0\bundled\tool\server.py
    0	    11	 18436	       console-window-host (Windows internal process)
    0	   298	 17788	     "C:\Users\lonelyteapot\AppData\Local\Programs\Microsoft VS Code\Code.exe" --ms-enable-electron-run-as-node c:\Users\lonelyteapot\.vscode\extensions\ms-python.vscode-pylance-2023.1.21\dist\server.bundle.js --cancellationReceive=file:caca6b18c4ac87a5720746b3863d197025bee20874 --node-ipc --clientProcessId=18880
    0	   124	 18628	     "C:\Users\lonelyteapot\AppData\Local\Programs\Microsoft VS Code\Code.exe" --ms-enable-electron-run-as-node c:\Users\lonelyteapot\.vscode\extensions\vue.volar-1.0.24-win32-x64\server.js --node-ipc --clientProcessId=18880

Workspace Info

|  Window (● __init__.py - Transit-at-Hand-Backend - Visual Studio Code)
|    Folder (Transit-at-Hand-Backend): 3 files
|      File types: gitignore(1) md(1)
|      Conf files:;

A/B Experiments

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vsreu685:30147344
python383cf:30185419
vspor879:30202332
vspor708:30202333
vspor363:30204092
vslsvsres303:30308271
pythonvspyl392:30443607
vserr242cf:30382550
pythontb:30283811
vsjup518:30340749
pythonptprofiler:30281270
vshan820:30294714
vstes263:30335439
pythondataviewer:30285071
vscod805:30301674
binariesv615:30325510
bridge0708:30335490
bridge0723:30353136
cmake_vspar411:30581797
vsaa593:30376534
pythonvs932:30410667
cppdebug:30492333
vscaat:30438848
vsclangdc:30486549
c4g48928:30535728
dsvsc012cf:30540253
azure-dev_surveyone:30548225
vscccc:30610679
pyindex848:30577860
nodejswelcome1cf:30587006
3biah626:30602489
f6dab269:30613381
fim-prod:30623723

---

.cpuprofile: CPU-20230114T203041.375Z.cpuprofile.txt (more info here).

[charliermarsh]

Yeah right now we lint on every keystroke. We could add some debouncing to accommodate certain setups.

[Donkie]

I have this issue too, would love to see some debouncing as you mentioned. It's not just that it causes high CPU usage, but the linter lags behind. It's computing the lint of things I wrote 20 keystrokes ago, of which result is not relevant anymore.

[DetachHead]

on my machine it seems to be queueing up hundreds of runs, which takes several minutes to finish. it makes the extension pretty much unusable

the output is also being spammed with these, not sure if that's relevant:

Cancel notification for unknown message id "38"
Cancel notification for unknown message id "37"
Cancel notification for unknown message id "41"
Cancel notification for unknown message id "40"
Cancel notification for unknown message id "43"
Cancel notification for unknown message id "44"
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Cancel notification for unknown message id "39"
Cancel notification for unknown message id "42"
Cancel notification for unknown message id "53"
Cancel notification for unknown message id "54"
Cancel notification for unknown message id "55"
Cancel notification for unknown message id "52"
Cancel notification for unknown message id "57"
Cancel notification for unknown message id "56"
Cancel notification for unknown message id "59"
Cancel notification for unknown message id "61"
Cancel notification for unknown message id "60"
Cancel notification for unknown message id "58"
Cancel notification for unknown message id "64"
Cancel notification for unknown message id "65"
Cancel notification for unknown message id "62"
Cancel notification for unknown message id "67"
Cancel notification for unknown message id "68"
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Cancel notification for unknown message id "75"

[VoodaGod]

any concrete plans for solving this yet? i'd be happy with the ability to only trigger the linting on save for example, if that's easier than debouncing

[charliermarsh]

We can probably provide a setting to only lint on-save.

[bigjools]

What about doing some sort of countback so it only does it every, say, 10 keystrokes in a certain time period?

[MichaReiser]

I wonder if it would help to change the sync setting to incremental and instead maintain a file map internally in the LSP. It would avoid that vscode sends the whole document on every keystroke.

Or do we support client cancellation? If not, than adding support for it could help to filter out delayed requests

[charliermarsh]

That’s an option. I believe that’s how ruffd works.

I don’t believe we support client cancellation. How would / does that work?

[MichaReiser]

I don’t believe we support client cancellation. How would / does that work?

The LSP protocol supports a cancelRequest operation and also mentions it in their consideration section. I wasn't able to find out if pygls supports it out of the box, or only when using async handlers.

I don't remember Rome running into this problem and Rome runs the linter on onChange too without any debounce (I believe the editor already debounces requests)

[DetachHead]

since this issue has made the ruff extension unusable for me, as a workaround i created a ruff task with a problem matcher that runs on save instead:

1. disable the ruff plugin
2. install the Trigger Task on Save extension
3. add the following to your vscode config files:

   // .vscode/extensions.json
   {
     "recommendations": ["gruntfuggly.triggertaskonsave"]
   }

   // .vscode/settings.json
   {
     "triggerTaskOnSave.tasks": {
         "ruff - current file": ["**/*.py"]
     }
   }

   // .vscode/tasks.json
   {
     "version": "2.0.0",
     "tasks": [
       {
         "label": "ruff - current file",
         "type": "process",
         // this assumes your project is using poetry. if it's not you'll have to change how this runs
         "command": "poetry",
         "args": ["run", "ruff", "--fix", "--fixable=I", "${file}"],
         "problemMatcher": {
           "fileLocation": ["relative", "${workspaceFolder}"],
           "owner": "python",
           "pattern": {
             "regexp": "^([^:]+):(\\d+):(\\d+): (.*)$",
             "file": 1,
             "line": 2,
             "column": 3,
             "message": 4
           },
           "severity": "warning"
         },
         "presentation": {
           "clear": true
         }
       }
     ]
   }

[charliermarsh]

I will take a look at this soon.

[charliermarsh]

I'm going to start by making this configurable. I'm going to mirror ESLint's extension which has a setting for this. Separately, I'm also going to look into making the entire extension async to improve performance and support cancellation.