extensionHost 100% CPU usage due to Prisma

[gkossakowski]

Type: Bug

Reproduce:

1. Open https://github.com/redwoodjs/redwood-tutorial in VSCode
2. Open schema.prisma
3. Watch 100% CPU usage that never goes down

Extension version: 4.1.0 VS Code version: Code 1.70.0 (da76f93349a72022ca4670c1b84860304616aaa2, 2022-08-04T04:39:20.716Z) OS version: Darwin arm64 21.6.0 Modes:

System Info

Item	Value
CPUs	Apple M1 Pro (10 x 24)
GPU Status	2d_canvas: enabled canvas_oop_rasterization: disabled_off direct_rendering_display_compositor: disabled_off_ok gpu_compositing: enabled metal: disabled_off 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 webgl: enabled webgl2: enabled
Load (avg)	10, 9, 8
Memory (System)	32.00GB (1.17GB free)
Process Argv	. --crash-reporter-id e55ceadf-1d93-4a73-8748-610272349188
Screen Reader	no
VM	0%

A/B Experiments

vsliv368cf:30146710
vsreu685:30147344
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vspor879:30202332
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vswsl492cf:30256860
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pythonvspyl392:30443607
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pythontb:30283811
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pythonptprofiler:30281270
vshan820:30294714
vstes263:30335439
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pythondataviewer:30285071
vscod805:30301674
binariesv615:30325510
bridge0708:30335490
bridge0723:30353136
vsaa593:30376534
vsc1dst:30438360
pythonvs932:30410667
wslgetstarted:30449410
vscscmwlcmt:30465135
cppdebug:30492333
vscaac:30438847
pylanb8912:30529769
vsclangdc:30486549
c4g48928:30535728
hb751961:30541207
dsvsc012:30540252

[gkossakowski]

Prisma ext was pinpointed with the Extension Bisect.

[janpio]

Is this reproducible? Does it go away if you disable the File Watcher in the Prisma Extension settings?

[gkossakowski]

It is 100% reproducible for me. Disabling File Watcher in the Prisma Extension settings makes the problem go away. Is disabling that setting safe to use as a work-around for now?

[janpio]

Definitely. It might surface a bug/problem in the Typescript server though, after you prisma generate it might not pick up the new types and hence underline some usage of prisma. in your code red. That is what the file watcher is trying to avoid by restarting the TS Server automatically, but you can also do that manually if it happens.

[gkossakowski]

Got it. Thanks for the explanation. File Watcher spinning 100% cpu indefinitely does still sound like a bug?

[janpio]

Yes, there should be multiple already.

[Jolg42]

Hi! @gkossakowski @rstrand @thgh

I created a PR to fix the file watcher issue, I'm happy to report that on my computer (macOS m1) it's now fixed. (CPU goes from ~100% previously to 0%)

Could you confirm it's also fixed for you as well?

Follow these instructions

First, confirm that the CPU usage is high using the Prisma extension from the VS Code marketplace

• Open your project using Prisma
• If you disabled the Prisma File Watcher functionality, enable it again from the command palette:
• Open the schema.prisma file from your project
• Use "Open Process Explorer" from VS Code' menu or open the OS Activity monitor
• Note / screenshot the CPU usage for the extension host above the Prisma extension process for the explorer or for the Activity Monitor, the Code Helper (Renderer) value and share it at the end

Second, confirm that with the new extension the CPU usage is low using a special build from my PR

Note: only the file watcher logic was changed.

• Uninstall any Prisma extension installed (uninstall is preferred as only disabling might interfere in some ways)
• Download https://github.com/prisma/language-tools/blob/artifacts/pull-request-artifacts/pr1243-prisma.vsix?raw=true
• Click "Install from VSIX" from this button (screenshot) or command palette and select the pr1243-prisma.vsix file
• Restart the VS Code application
• Open the schema.prisma file from your project
• Use "Open Process Explorer" from VS Code' menu or open the OS Activity monitor
• Note / screenshot the CPU usage for the extension host above the Prisma extension process for the explorer or for the Activity Monitor, the Code Helper (Renderer) value and share it at the end

Third, if you have a TypeScript project, confirm that the file watcher works and that the types are refreshed

• Open a TypeScript file from your project where you have Prisma Client queries like await prisma.user.findMany()
• Open the schema.prisma file from your project
• Both should have no errors
• Edit the schema.prisma file and delete all the models (only keep the datasource & generator blocks)
• Run npx prisma generate
• In your TypeScript file, you should now instantly see a Type Error that should look like the following
• Undo the changes in your schema.prisma
• Run npx prisma generate
• The Type Error(s) in the TypeScript file should be gone now

Please share something like the following: I tested on ... (macOS m1, Windows, Linux....)

1. Current extension: screenshot showing ~91% CPU (Note: CPU is only reported on the aggregated top line for some reason)
2. Using pr1243-prisma.vsix, screenshot after showing ~0% CPU usage 🎊
3. The typings were updated successfully after npx prisma generate, a Type Error was visible ✅

Thank you in advance 💚 Note: I'm waiting for some feedback before we switch to this new low CPU file watcher in a stable release on VS Code marketplace.

[Jolg42]

The fix is now in the latest 4.4.0 version on the marketplace https://marketplace.visualstudio.com/items?itemName=Prisma.prisma 🎊

For those who disabled the File Watcher functionality, you can enable it again.