Scrolling (and rendering in general) is extremely slow

[zareami10]

Ever since the release of the new jupyter version, the performance of the extension has dropped dramatically. Scrolling is laggy, rendering outputs eats the CPU and even the progress bar can be 10fps per second with any notebook larger than a couple of cells.

And this is not corner case issue, I have had this problem on many different machines and even different OSes.

In comparison jupyter on a browser is at least 20 times faster/smoother.

[rebornix]

@zareami10 thanks for your feedback. It would be great if we can get more information to troubleshoot this issue. It seems there are multiple issues:

• Scrolling is laggy. This is very likely due to the nature of virtualization.
• rendering outputs eats the CPU and even the progress bar can be 10fps per second with any notebook larger than a couple of cells. This is interesting and currently I don't have any clue how is that happening. Would it be fine that when you run into the same issue again, share the notebook and a recording of what you are seeing with us?

[zareami10]

This is very likely due to the nature of virtualization.

I'm not really aware of the internals of the extension, can you please elaborate? Because it's bad enough to hinder working with any medium-sized notebooks, and I end up switching to the browser.

Would it be fine that when you run into the same issue again, share the notebook and a recording of what you are seeing with us?

Sure, but about the very high CPU-usage, I believe it mostly happens when there are outputs being shown/updated as the notebook runs.

[rebornix]

@zareami10

I'm not really aware of the internals of the extension, can you please elaborate? Because it's bad enough to hinder working with any medium-sized notebooks, and I end up switching to the browser.

Do you mind running following commands to help collect logs for the slowness you are seeing?

• Menu -> Help -> Toggle Developer Tools
• Open Performance Page from the Developer Tools
• Click the first round icon to start recording
• Scrolling in the editor
• Hit the round icon again to stop recording
• Click the 5th icon to download the log and share with us

Sure, but about the very high CPU-usage, I believe it mostly happens when there are outputs being shown/updated as the notebook runs

Does the CPU go high when you are using the browser or it only happens with VS Code? Any pattern of the code you are running?

[zareami10]

@zareami10

I'm not really aware of the internals of the extension, can you please elaborate? Because it's bad enough to hinder working with any medium-sized notebooks, and I end up switching to the browser.

Do you mind running following commands to help collect logs for the slowness you are seeing?

* Menu -> Help -> Toggle Developer Tools

* Open Performance Page from the Developer Tools

* Click the first round icon to start recording

* Scrolling in the editor

* Hit the round icon again to stop recording

* Click the 5th icon to download the log and share with us

Sure, but about the very high CPU
-usage, I believe it mostly happens when there are outputs being shown/updated as the notebook runs

Does the CPU go high when you are using the browser or it only happens with VS Code? Any pattern of the code you are running?

@rebornix

I have attached a profile on a kinda low-end hardware. But the situation is the same on stronger machines. Will profile on another machine with a dGPU too.

Profile-20220423T212859.json.zip

[zareami10]

This is the other profilng:

Profile-20220423T223925.zip

Also no it only happens in Code. And my notebooks aren't really anything specific.

[vscodenpa]

This issue has been closed automatically because it needs more information and has not had recent activity. See also our issue reporting guidelines.

Happy Coding!