High CPU usage with VSConfig nRF Kconfig extension

[Florian Zierer]

The  VSCode nRF Kconfig extension has very high cpu usage (2 cores at 100%)

When disabling the extension, the cpu usage drops back to normal.

I see the following in the VSCode Window Output

2025-05-19 23:22:36.399 [info] [Views] Added views:workbench.scm.repositories in workbench.view.scm
2025-05-19 23:22:36.405 [info] [Views] Added views:workbench.scm.history in workbench.view.scm
2025-05-19 23:22:36.433 [info] [Views] Added views:nrf-connect.allAppsView in workbench.view.extension.nrf-connect
2025-05-19 23:22:38.844 [error] [Window] TreeError [DebugRepl] Tree input not set: Error: TreeError [DebugRepl] Tree input not set
    at Gf.C (vscode-file://vscode-app/usr/share/code/resources/app/out/vs/workbench/workbench.desktop.main.js:417:29043)
    at Gf.updateChildren (vscode-file://vscode-app/usr/share/code/resources/app/out/vs/workbench/workbench.desktop.main.js:417:28950)
    at Wne.value (vscode-file://vscode-app/usr/share/code/resources/app/out/vs/workbench/workbench.desktop.main.js:2092:33670)
    at E.B (vscode-file://vscode-app/usr/share/code/resources/app/out/vs/workbench/workbench.desktop.main.js:29:2392)
    at E.C (vscode-file://vscode-app/usr/share/code/resources/app/out/vs/workbench/workbench.desktop.main.js:29:2462)
    at E.fire (vscode-file://vscode-app/usr/share/code/resources/app/out/vs/workbench/workbench.desktop.main.js:29:2680)
    at x1e.setVisible (vscode-file://vscode-app/usr/share/code/resources/app/out/vs/workbench/workbench.desktop.main.js:680:2727)
    at vscode-file://vscode-app/usr/share/code/resources/app/out/vs/workbench/workbench.desktop.main.js:1308:11769
    at Array.map (<anonymous>)
    at ju.setVisible (vscode-file://vscode-app/usr/share/code/resources/app/out/vs/workbench/workbench.desktop.main.js:1308:11760)
2025-05-19 23:22:39.892 [info] [Views] Added views:nrf-connect.detailsView,nrf-connect.actionsView in workbench.view.extension.nrf-connect
2025-05-19 23:25:09.829 [error] [Window] Extension host (LocalProcess pid: 26218) terminated unexpectedly. The following extensions were running: vscode.github-authentication, vscode.emmet, nordic-semiconductor.nrf-kconfig, vscode.git-base, mhutchie.git-graph, nordic-semiconductor.nrf-connect-extension-pack, nordic-semiconductor.nrf-terminal, vscode.configuration-editing, vscode.json-language-features, vscode.typescript-language-features, yzhang.markdown-all-in-one, vscode.markdown-math, vscode.git, vscode.github, nordic-semiconductor.nrf-connect, nordic-semiconductor.nrf-devicetree, ms-vscode.cpptools, vscode.debug-auto-launch, vscode.merge-conflict
2025-05-19 23:25:09.829 [info] [Window] Automatically restarting the extension host.
2025-05-19 23:25:09.856 [info] [Views] Removed views:workbench.scm.history from workbench.view.scm
2025-05-19 23:25:09.858 [info] [Views] Removed views:workbench.scm.repositories from workbench.view.scm
2025-05-19 23:25:09.901 [info] [Window] Started local extension host with pid 28275.
2025-05-19 23:25:10.128 [info] [Views] Removed views:workbench.panel.repl.view from workbench.panel.repl
2025-05-19 23:25:10.134 [info] [Views] Removed views:workbench.debug.callStackView,workbench.debug.watchExpressionsView,workbench.debug.variablesView from workbench.view.debug

Ubuntu 24.10

VSCode 1.100.2,

Extension: 

  - nordic-semiconductor.nrf-connect 2025.5.92

 -nordic-semiconductor.nrf-kconfig, 2025.4.26

[23:46:19] =========== Toolchain validation report for nRF Connect SDK Toolchain v3.0.1 ===========

 Using the nRF Connect SDK v3.0.1 at /home/xxx/ncs/v3.0.1

No issues were detected with the toolchain.

[Charlie]

Hi Florian,

Thanks for checking with us about this issue.

According to the official documentation, Ubuntu 24.10 is not officially supported at the moment. Would you have a chance to test on Ubuntu 24.04 x64 instead?

It's also not clear whether the high CPU usage is caused by the nRF Connect for VS Code extension itself or by the installed NCS v3.0.1. Could you try checking the CPU usage when only the nRF Connect extension is installed, without installing NCS?

Best regards,
Charlie

[pzaremba]

Same here with Ubuntu 22.04.  That extension caused me hours of frustration before I stumbled upon these threads.

[Charlie]

Hi pzaremba,

Thanks for reporting this issue.

Does the high CPU usage occur when only the nRF Connect extension is installed, without any NCS version installed?
Have you also tested with previous versions of the extension to see if the issue persists?

We would appreciate any additional details you can share, such as your system specs, extension version, and a log or screenshot, to help us investigate and address the issue more effectively.

Best regards,
Charlie

[Florian Zierer]

It is a bit strange and seems not to be related to the Ubuntu Version.

I tested it on another PC with Ubuntu 22.04 (I don't have 24.04 available) as pzaremba but there I don't see the high CPU usage.

I am now using ncs v3.0.1 and toolchain v3.0.2

The issue persists on Ubuntu 24.10 with these versions.

[Charlie]

Maybe you can share you PC HW details or PC model to see if anyone get the same issue with this specific PC/Laptop.