VSCode freezes when moving between files

[mrleemurray]

Does this issue occur when all extensions are disabled?: No

Version: 1.102.0-insider (Universal)
Commit: ed787a5
Date: 2025-06-16T18:16:54.725Z
Electron: 35.5.1
ElectronBuildId: 11727614
Chromium: 134.0.6998.205
Node.js: 22.15.1
V8: 13.4.114.21-electron.0
OS: Darwin arm64 24.5.0

Steps to Reproduce:

1. Add a project
2. Find a property / class / variable, right click on it & choose Go to Definition
3. The UI will freeze for up to 30 seconds

vscode.freezing.2025-06-17.11-22-26.mov

The console was returning this error repeatedly:

[deepak1556]

Can you follow the steps from https://github.com/microsoft/vscode/wiki/Runtime-debugging#cpu-profiling-unresponsive-window-via-tracing and attach the trace file to this issue. Thanks!

[deepak1556]

@mrleemurray next time you hit this can you also capture an extension host cpu profile following the steps , difference from the above is that it avoids a restart of the application.

1. Run the command node -e "process.kill($pid, 'SIGUSR1')"; lsof -i TCP | grep -E "\b$pid\b"; from terminal. Replace $pid with the pid of the extension host you want to debug
2. Open localhost:<port>/json from any chromium based browser, replace with the value that got printed in the above command
3. Copy the value of devtoolsFrontendUrl from the resulting web page and open a new tab in the browser with that url
4. You will now have a devtools session connected to the extension host process, visit the performance tab and start profiling. Stop the profile after a 10-20s or if the window becomes responsive again.

[deepak1556]

We have a built-in sampler for the workbench that kicks in during the unresponsive event, the following were the stacks that got captured for the OP scenario which matches the error related to tokenizer https://gist.github.com/deepak1556/28438d7d37cf8518b3ac31c96312e9ec.

/cc @hediet can you take a look, don't think we have a full picture here since some activity from the extension host contributed to the issue and we don't have info on it. But incase anything jumps to you from the workbench samples and any additional logs you can follow-up on.

[hediet]

In the past, this has caused freezes of the bracket pair colorization algorithm that are mostly consistent with the video (but we fixed that).
It wouldn't explain the extension host freeze though.

In any case, freezing bracket pair colorization is only a symptom and not the root cause.
We need to figure out what the root cause is.
Did you turn on tree sitter?

[mrleemurray]

@deepak1556 how do I get the pid of the extensionhost?

[mrleemurray]

@hediet these are my current settings:

Should I disable tree sitter?

[hediet]

Should I disable tree sitter?

If you can reproduce without tree sitter, it would increase the importance of a quick bug fix significantly!

[deepak1556]

how do I get the pid of the extensionhost?

from Help -> Open Process explorer