`autoTestDiscoverOnSaveEnabled` setting causing significant decreases in VS Code performance

[mudit2812]

Type: Bug

I ran extension bisect to figure out which extension was causing trouble with the performance of VS Code on my machine. Extension Bisect led to detecting vscode-python (and associated extensions pylint, isort, pylance) to be the problem causers. The troubles I commonly encounter include:

• Using the built-in source control to stage changes, commit, push, pull changes, etc. can take over 10 minutes
• Built in debugger takes over 10 minutes to start execution and sometimes gets stuck while stepping over/into lines after a break point
• Copy/pasting, deleting, creating files/folders using the file explorer takes a very long time
• Can't create new lines in code so I need to resort to copy-pasting new lines since the Enter key doesn't do anything.

The only way I can fix performance is by reloading the window, which I have to do over 10 times a day because the slowdowns are very consistent. This is a big headache for me as I code almost exclusively in Python.

Extension version: 2023.10.1 VS Code version: Code 1.79.0 (Universal) (b380da4ef1ee00e224a15c1d4d9793e27c2b6302, 2023-06-07T14:29:00.206Z) OS version: Darwin arm64 22.5.0 Modes:

System Info

|Item|Value| |---|---| |CPUs|Apple M1 (8 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
video_decode: enabled
video_encode: enabled
vulkan: disabled_off
webgl: enabled
webgl2: enabled
webgpu: enabled| |Load (avg)|3, 2, 2| |Memory (System)|16.00GB (0.15GB free)| |Process Argv|--crash-reporter-id 0bdbd0bc-c581-437f-8eff-d3312dcce3ec| |Screen Reader|no| |VM|0%|

A/B Experiments

``` vsliv368:30146709 vsreu685:30147344 python383cf:30185419 vspor879:30202332 vspor708:30202333 vspor363:30204092 vswsl492:30256859 vslsvsres303:30308271 vserr242cf:30382550 pythontb:30283811 vsjup518:30340749 pythonptprofiler:30281270 vshan820:30294714 vstes263cf:30335440 vscoreces:30445986 vscod805cf:30301675 binariesv615:30325510 bridge0708:30335490 bridge0723:30353136 vsaa593cf:30376535 pythonvs932:30410667 vsclangdf:30486550 c4g48928:30535728 dsvsc012:30540252 pynewext54:30695312 azure-dev_surveyone:30548225 3biah626:30602489 pyind779:30671433 f6dab269:30613381 pythonsymbol12:30671437 a9j8j154:30646983 showlangstatbar:30737416 vsctsb:30748421 pythonms35:30701012 03d35959:30757346 pythonfmttext:30731395 pythoncmv:30756943 fixshowwlkth:30730052 showindicator:30766890 pythongtdpath:30739704 i26e3531:30763805 dh2dc718:30763024 ```

[karthiknadig]

This might be due to file system watching, can you enable these logs to see if it is being triggered to often. Would it be possible for you to provide a minimal repro or a repository that we can use to repro this.

Logging (local) !!! This is ONLY when you open a local workspace, for remote see below !!! We provide logging for file events when you enable verbose logging. Steps are:

• open VSCode on the local workspace that shows the issue
• select View | Command Palette...
• select Developer - Set Log Level...
• pick Trace
• select Help | Toggle Developer Tools
• select Console
• filter the output by typing File Watcher into the filter box
• attach the output when doing the operation that exhibits the issue

Logging (remote) !!! This is ONLY when you open a remote workspace (WSL, Docker, SSH), for local see above !!! We provide logging for file events when you enable verbose logging. Steps are:

• open VSCode on the remote workspace that shows the issue
• select View | Command Palette...
• select Developer - Set Log Level...
• pick Trace
• select View | Output
• select Log (Remote Server) from the dropdown
• attach the output when doing the operation that exhibits the issue

[mudit2812]

I set the

"python.testing.autoTestDiscoverOnSaveEnabled": true

setting to false and the slowdown disappeared completely. I will enable it and attach the file watcher output once I'm able to replicate the error.

Would it be possible for you to provide a minimal repro or a repository that we can use to repro this.

I'm working on the PennyLane repository. There are a lot of tests, which could be why this setting being enabled impacts performance so much.

[mudit2812]

Here's a snippet of the file watcher when I was noticing the performance degradation. The two major things I noticed were:

• Not being able to create new lines
• Git extension would not let me stage/commit changes

log.ts:401 TRACE [File Watcher (parcel)] [DELETED] /Users/mudit.pandey/repos/braket-plugin-fork/.tox/unit-tests/log/2-commands[0].log
log.ts:401 TRACE [File Watcher (parcel)]  >> normalized [DELETED] /Users/mudit.pandey/repos/braket-plugin-fork/.tox/unit-tests/log/2-commands[0].log
log.ts:401 TRACE [File Watcher (parcel)]  >> normalized [CHANGED] /Users/mudit.pandey/repos/braket-plugin-fork/.tox/unit-tests/log/1-install_package.log
log.ts:401 TRACE [File Watcher (parcel)] [ADDED] /Users/mudit.pandey/repos/braket-plugin-fork/test/unit_tests/__pycache__/test_translation.cpython-310-pytest-7.4.0.pyc
log.ts:401 TRACE [File Watcher (parcel)] [DELETED] /Users/mudit.pandey/repos/braket-plugin-fork/test/unit_tests/__pycache__/test_translation.cpython-310-pytest-7.4.0.pyc.83295
log.ts:401 TRACE [File Watcher (parcel)] [DELETED] /Users/mudit.pandey/repos/braket-plugin-fork/test/unit_tests/__pycache__/test_translation.cpython-310-pytest-7.4.0.pyc.83298
log.ts:401 TRACE [File Watcher (parcel)] [DELETED] /Users/mudit.pandey/repos/braket-plugin-fork/test/unit_tests/__pycache__/test_translation.cpython-310-pytest-7.4.0.pyc.83299
log.ts:401 TRACE [File Watcher (parcel)] [DELETED] /Users/mudit.pandey/repos/braket-plugin-fork/test/unit_tests/__pycache__/test_translation.cpython-310-pytest-7.4.0.pyc.83302
log.ts:401 TRACE [File Watcher (parcel)] [DELETED] /Users/mudit.pandey/repos/braket-plugin-fork/test/unit_tests/__pycache__/test_translation.cpython-310-pytest-7.4.0.pyc.83306
log.ts:401 TRACE [File Watcher (parcel)] [DELETED] /Users/mudit.pandey/repos/braket-plugin-fork/test/unit_tests/__pycache__/test_translation.cpython-310-pytest-7.4.0.pyc.83309
log.ts:401 TRACE [File Watcher (parcel)] [ADDED] /Users/mudit.pandey/repos/braket-plugin-fork/test/unit_tests/__pycache__/test_translation.cpython-310-pytest-7.4.0.pyc
log.ts:401 TRACE [File Watcher (parcel)] [DELETED] /Users/mudit.pandey/repos/braket-plugin-fork/test/unit_tests/__pycache__/test_translation.cpython-310-pytest-7.4.0.pyc.83298
log.ts:401 TRACE [File Watcher (parcel)] [DELETED] /Users/mudit.pandey/repos/braket-plugin-fork/test/unit_tests/__pycache__/test_translation.cpython-310-pytest-7.4.0.pyc.83300
log.ts:401 TRACE [File Watcher (parcel)] [DELETED] /Users/mudit.pandey/repos/braket-plugin-fork/test/unit_tests/__pycache__/test_translation.cpython-310-pytest-7.4.0.pyc.83301
log.ts:401 TRACE [File Watcher (parcel)]  >> normalized [DELETED] /Users/mudit.pandey/repos/braket-plugin-fork/test/unit_tests/__pycache__/test_translation.cpython-310-pytest-7.4.0.pyc.83295
log.ts:401 TRACE [File Watcher (parcel)]  >> normalized [DELETED] /Users/mudit.pandey/repos/braket-plugin-fork/test/unit_tests/__pycache__/test_translation.cpython-310-pytest-7.4.0.pyc.83298
log.ts:401 TRACE [File Watcher (parcel)]  >> normalized [DELETED] /Users/mudit.pandey/repos/braket-plugin-fork/test/unit_tests/__pycache__/test_translation.cpython-310-pytest-7.4.0.pyc.83299
log.ts:401 TRACE [File Watcher (parcel)]  >> normalized [DELETED] /Users/mudit.pandey/repos/braket-plugin-fork/test/unit_tests/__pycache__/test_translation.cpython-310-pytest-7.4.0.pyc.83302
log.ts:401 TRACE [File Watcher (parcel)]  >> normalized [DELETED] /Users/mudit.pandey/repos/braket-plugin-fork/test/unit_tests/__pycache__/test_translation.cpython-310-pytest-7.4.0.pyc.83306
log.ts:401 TRACE [File Watcher (parcel)]  >> normalized [DELETED] /Users/mudit.pandey/repos/braket-plugin-fork/test/unit_tests/__pycache__/test_translation.cpython-310-pytest-7.4.0.pyc.83309
log.ts:401 TRACE [File Watcher (parcel)]  >> normalized [DELETED] /Users/mudit.pandey/repos/braket-plugin-fork/test/unit_tests/__pycache__/test_translation.cpython-310-pytest-7.4.0.pyc.83300
log.ts:401 TRACE [File Watcher (parcel)]  >> normalized [DELETED] /Users/mudit.pandey/repos/braket-plugin-fork/test/unit_tests/__pycache__/test_translation.cpython-310-pytest-7.4.0.pyc.83301
log.ts:401 TRACE [File Watcher (parcel)]  >> normalized [ADDED] /Users/mudit.pandey/repos/braket-plugin-fork/test/unit_tests/__pycache__/test_translation.cpython-310-pytest-7.4.0.pyc
log.ts:401 TRACE [File Watcher (parcel)] [ADDED] /Users/mudit.pandey/repos/braket-plugin-fork/.coverage.MacBookAir-FVFG339QQ6LR.83301.031808
log.ts:401 TRACE [File Watcher (parcel)] [ADDED] /Users/mudit.pandey/repos/braket-plugin-fork/.coverage.MacBookAir-FVFG339QQ6LR.83306.705163
log.ts:401 TRACE [File Watcher (parcel)]  >> normalized [ADDED] /Users/mudit.pandey/repos/braket-plugin-fork/.coverage.MacBookAir-FVFG339QQ6LR.83301.031808
log.ts:401 TRACE [File Watcher (parcel)]  >> normalized [ADDED] /Users/mudit.pandey/repos/braket-plugin-fork/.coverage.MacBookAir-FVFG339QQ6LR.83306.705163
log.ts:401 TRACE [File Watcher (parcel)] [ADDED] /Users/mudit.pandey/repos/braket-plugin-fork/.coverage.MacBookAir-FVFG339QQ6LR.83299.207696
log.ts:401 TRACE [File Watcher (parcel)] [ADDED] /Users/mudit.pandey/repos/braket-plugin-fork/.coverage.MacBookAir-FVFG339QQ6LR.83300.822956
log.ts:401 TRACE [File Watcher (parcel)] [CHANGED] /Users/mudit.pandey/repos/braket-plugin-fork/.coverage.MacBookAir-FVFG339QQ6LR.83301.031808
log.ts:401 TRACE [File Watcher (parcel)] [CHANGED] /Users/mudit.pandey/repos/braket-plugin-fork/.coverage.MacBookAir-FVFG339QQ6LR.83306.705163
log.ts:401 TRACE [File Watcher (parcel)]  >> normalized [ADDED] /Users/mudit.pandey/repos/braket-plugin-fork/.coverage.MacBookAir-FVFG339QQ6LR.83299.207696
log.ts:401 TRACE [File Watcher (parcel)]  >> normalized [ADDED] /Users/mudit.pandey/repos/braket-plugin-fork/.coverage.MacBookAir-FVFG339QQ6LR.83300.822956
log.ts:401 TRACE [File Watcher (parcel)]  >> normalized [CHANGED] /Users/mudit.pandey/repos/braket-plugin-fork/.coverage.MacBookAir-FVFG339QQ6LR.83301.031808
log.ts:401 TRACE [File Watcher (parcel)]  >> normalized [CHANGED] /Users/mudit.pandey/repos/braket-plugin-fork/.coverage.MacBookAir-FVFG339QQ6LR.83306.705163
log.ts:401 TRACE [File Watcher (parcel)] [ADDED] /Users/mudit.pandey/repos/braket-plugin-fork/.coverage.MacBookAir-FVFG339QQ6LR.83298.055672
log.ts:401 TRACE [File Watcher (parcel)]  >> normalized [ADDED] /Users/mudit.pandey/repos/braket-plugin-fork/.coverage.MacBookAir-FVFG339QQ6LR.83298.055672
log.ts:401 TRACE [File Watcher (parcel)] [CHANGED] /Users/mudit.pandey/repos/braket-plugin-fork/.coverage.MacBookAir-FVFG339QQ6LR.83298.055672
log.ts:401 TRACE [File Watcher (parcel)] [ADDED] /Users/mudit.pandey/repos/braket-plugin-fork/.coverage.MacBookAir-FVFG339QQ6LR.83302.070035
log.ts:401 TRACE [File Watcher (parcel)]  >> normalized [CHANGED] /Users/mudit.pandey/repos/braket-plugin-fork/.coverage.MacBookAir-FVFG339QQ6LR.83298.055672
log.ts:401 TRACE [File Watcher (parcel)]  >> normalized [ADDED] /Users/mudit.pandey/repos/braket-plugin-fork/.coverage.MacBookAir-FVFG339QQ6LR.83302.070035
log.ts:401 TRACE [File Watcher (parcel)] [ADDED] /Users/mudit.pandey/repos/braket-plugin-fork/.coverage.MacBookAir-FVFG339QQ6LR.83309.636014
log.ts:401 TRACE [File Watcher (parcel)]  >> normalized [ADDED] /Users/mudit.pandey/repos/braket-plugin-fork/.coverage.MacBookAir-FVFG339QQ6LR.83309.636014
log.ts:401 TRACE [File Watcher (parcel)] [ADDED] /Users/mudit.pandey/repos/braket-plugin-fork/.coverage
log.ts:401 TRACE [File Watcher (parcel)] [ADDED] /Users/mudit.pandey/repos/braket-plugin-fork/.coverage.MacBookAir-FVFG339QQ6LR.83295.542263
log.ts:401 TRACE [File Watcher (parcel)] [DELETED] /Users/mudit.pandey/repos/braket-plugin-fork/.coverage.MacBookAir-FVFG339QQ6LR.83299.207696
log.ts:401 TRACE [File Watcher (parcel)] [DELETED] /Users/mudit.pandey/repos/braket-plugin-fork/.coverage.MacBookAir-FVFG339QQ6LR.83300.822956
log.ts:401 TRACE [File Watcher (parcel)] [DELETED] /Users/mudit.pandey/repos/braket-plugin-fork/.coverage.MacBookAir-FVFG339QQ6LR.83302.070035
log.ts:401 

[karthiknadig]

I think there might be two different problems here:

1. I think the filtering for file watching should exclude pyc I think this might be causing the problem.
2. For the Git extension issue it might be independent of this

/cc @eleanorjboyd Could you take a look at the pattern we use for file system watching in testing to see if we get *.pyc events?

[eleanorjboyd]

closing since the fix will be the same as https://github.com/microsoft/vscode-python/issues/21014. Thanks!