VS Code extension causes intermittent high CPU in window renderer on Fedora 43

Summary

The OpenAI Codex / ChatGPT VS Code extension appears to cause intermittent high CPU usage in the VS Code window renderer.

This is not the Go app in the workspace, not gopls, and not the GPU path.

Environment

• VS Code: 1.115.0
• VS Code commit: 41dd792b5e652393e7787322889ed5fdc58bd75b
• Extension: openai.chatgpt-26.409.20454-linux-x64
• OS: Fedora 43
• Kernel: 6.19.11-200.fc43.x86_64
• CPU: AMD Ryzen 7 5800HS with Radeon Graphics

Symptoms

• intermittent CPU spikes in the VS Code window renderer
• spikes happen even when the project itself is mostly idle
• the hot process is the VS Code window/renderer process, not the extension host
• disabling GPU does not help
• disabling extensions fixes the issue
• re-enabling the Codex extension appears to bring it back

What I Observed

From code --status:

CPU %   Mem MB     PID  Process
    4   143739525896      6534  window [1] (settings.json - wcs-core - Visual Studio Code)
    0   114991620717      6638  extension-host [1]
    0   17248743108       6658  file-watcher [1]

From process inspection:

/usr/share/code/code --type=zygote

From sampled CPU data:

02:20:00 AM  1000      6534         -  123.76    6.93    0.00    0.99  130.69     0  code
02:20:00 AM  1000         -      6534   22.77    3.96    0.00    0.99   26.73     0  |__code
02:20:00 AM  1000         -      6542   12.87    0.99    0.00    0.00   13.86     2  |__ThreadPoolForeg
02:20:00 AM  1000         -      6544   14.85    0.00    0.00    0.00   14.85    11  |__ThreadPoolForeg
02:20:00 AM  1000         -      6610   14.85    0.00    0.00    0.00   14.85     9  |__ThreadPoolForeg
02:20:00 AM  1000         -      6611   14.85    0.00    0.00    0.00   14.85     1  |__ThreadPoolForeg
02:20:00 AM  1000         -      6612   13.86    0.00    0.00    0.00   13.86    15  |__ThreadPoolForeg
02:20:00 AM  1000         -      6614   13.86    0.00    0.00    0.99   13.86     3  |__ThreadPoolForeg

This looks like renderer-side work spread across multiple Chromium/Electron worker threads.

What I Tried

• ran the noisy Python job outside the VS Code integrated terminal
• set terminal scrollback lower
• reduced watcher/search/Git churn in workspace settings
• ran code --disable-gpu
• ran code --disable-extensions

Results

• moving Python out of the integrated terminal reduced one trigger, but did not fully solve it
• code --disable-gpu did not change the issue
• code --disable-extensions made the problem go away
• the issue appears to return when the Codex extension is enabled again

Expected Behavior

The extension should not cause intermittent high CPU in the VS Code window renderer during normal use or low-activity periods.

Actual Behavior

With the extension enabled, the VS Code window renderer intermittently uses high CPU across multiple worker threads.

Additional Notes

• this looks more like renderer/UI/webview/decorations/terminal integration work than GPU or backend work
• the extension host itself was not the hot process during the captures

Attachments

I also collected a more detailed local report with:

• code --status
• ps, top -H, pidstat
• process tree and /proc snapshots