High CPU usage in WSL after last update

[Salmondx]

After recent update of VSCode, a CPU usage of a node process from vscode-remote extension is incredibly high. This process constantly consumes 30-40% of CPU.

VSCode version: 1.54.1
vscode-remote extension version: 0.54.2
WSL 1
Ubuntu 18.04

I tried to run vscode's developer tools to check resources usage and to collect performance profile, it doesn't show anything. Also disabling all other extensions doesn't help. Obviously it works ok only when I run vscode natively in windows, not from WSL.

Any ideas why it is happening and what info I can provide to you to help with debugging?

[Salmondx]

Rolling back to the previous version of extension (1.54.0) also didn't help. Looks like the problem is again with WSL? Any suggestions how to debug what is causing node to consume so much CPU in idle?

[Salmondx]

microsoft/WSL#4898

I tried to follow this issue, but my libc version is 2.27-3ubuntu1.4, not >=2.30

[aeschli]

Can you check the Process Explorer (Help > Open Process Explorer) and scroll to the bottom to the WSL processes? Would be interesting to see which process is busy.

[Salmondx]

Thanks for a response! Looks like process explorer shows that wsl processes doesn't consume any resources:

But at the same time this is what I see in windows task manager:

And if I open file location of this process, it opens folder with vscode-remote extension:

[telecasterer]

I have the exact same issue

[aeschli]

Can you set "remote.WSL.fileWatcher.polling": false and see if the problem goes away?

[telecasterer]

Can you set "remote.WSL.fileWatcher.polling": false and see if the problem goes away?

Thanks but that doesn't fix it for me.

[Salmondx]

@aeschli tried to disable polling and it helped. So something is broken with file polling in a new vscode release/WSL?

[Piroro-hs]

I have the same issue and disabling the polling helped (CPU usage by node process 50% -> 1%).
VSCode: 1.54.1
Remote - WSL: 0.54.3
Windows: 10.0.19042
WSL: 1
Ubuntu: 18.04

[aeschli]

watching by file polling is CPU costly by nature. It's basically scanning the open folder every 5 seconds (Can be configured by remote.WSL.fileWatcher.pollingInterval).

But polling is currently the only way to get reliable file events when on a /mnt/...

[Salmondx]

I'm using WSL and vscode-remote extension since it was released, and I never had such problem until recent vscode release. In the exact same environment, without any changes it was working fine until ~week ago.

Maybe they changed a default polling interval or something else?

[aeschli]

I have now disabled polling by default. Published ms-vscode-remote.remote-wsl@0.54.5