meta: VS Code Vim becomes very very slow

[trusktr]

Many people report this plugin slows down.

For me it becomes unbearably slow after a while (f.e. 1 key stroke per second, and they all get backed up while other VS Code actions can happen mid-way causing jumbled results).

Possibly related:

• Intermittent: Lag With Sticky Scroll After Prolonged Use #9708
• Vim slowing coding down #8924
• Slow line movement #8557
• vim is tooooooooooo slow #8517
• Significant Performance Degradation on Large File #8115
• slows down typing and vscode #7898
• acctually your vim extention is great and i love it but there is a small problem, its pretty slow sometimes it lags please solve this problem #7804
• Super Slow Typing in Insert Mode #7546
• Keystroke lag in TypeScript #7415
• Performance problems of vscode-vim can cause delayed typing #7274
• maybe Vim extension takes slowly when used to edit docs and files #6628
• Navigation unresponsive on large files #6589
• My VS Code Vim becomes super slow after messing up the macros (maybe?) #5339
• Inserting text makes VS Code unusably slow #4728
• VSCodeVim makes quick suggestions slow (includes video demonstration) #4598 (comment)
• undo/redo search and replace operations is non-atomic and slow #4293
• When typing too fast, Vim keystrokes ignored, VS Code does other things #4283
• Vim gets very slow, the longer VSCode seems to be open #3957
• Extremely slow when typing (limited to a special row) #3508
• Very Slow Text Editing #8887
• Text entry lag and lost keypresses on v1.26.0 #8573
• I may give up vscode because of the performance problems caused by the plug-in #7301
• Moving up and down the line using <number>j or <number>k is not instantaneous #6830 (still a problem)
• HUGE performance toll on VS Code, whole WIN 10 system WHEN combined with "Git for Windows"< 2.30- extension/VSC unusable  #6169
• << substantially slower than >> #5188 (still problematic)
• Lag exiting insert mode: normal mode keystrokes are getting entered as text after ESC #4941 (still problematic)
• Scrolling with <C-e> and <C-y> is very laggy #4309
• ViM extension makes VSCode super slow, typing is almost impossible. #4088
• Very slow on big files. #3924
• catastrophic performance #3654

(I went to page 2 only, for both open and closed issues, searching "slow")

Related:

• Insert mode keystrokes are sometimes dropped since 1.26.0 #8603

It might be "Microsoft's" fault for the extension API design? From #4598 (comment):

FWIW, I just tried amVim and it has the same issue. Perhaps the Extension Host is to blame for this? I would not be surprised, I think the Extension Host is garbage, and causes way more problems than it was intended to solve. (VSCodeVim commands do have to run in the separate extension host process right? It's pretty ridiculous for every key press to be doing IPC roundtrips, which is why I hate the Extension Host architecture for giving you no other option...)

I switched to Simple Vim

and it is a lot smoother.

In insert mode, it's just native VS Code, and the plugin listens only for Escape to go back to Normal mode. It's not as full featured, but enough for me to get productive without slowdowns, and to save my sanity.

Simple Vim still suffers from the same issues (seems like Extension Host), but it's doing a lot less so the issues aren't as pronounced.

[teslae1]

Agreed this is a problem - I am currently awaiting a review on a pr that reduces a tiny bit of overhead foreach keypress #9874

[orkansama]

+1

[ckingdon]

+1
It's bordering on unusable for me now.

[trusktr]

I couldn't withstand the slowness anymore.

I switched to Simple Vim

and it is a lot smoother.

In insert mode, it's just native VS Code, and the plugin listens only for Escape to go back to Normal mode. It's not as full featured, but enough for me to get productive without slowdowns, and to save my sanity.

Normal mode can still slow down, but it is nowhere near as bad as Insert mode in VSCodeVim. It seems the Extension Host is an overall problem all extensions face. But at least Insert in Simple Vim mode is vanilla VS Code, which really helps, because writing was grinding to a halt.

Problem with VS Code Vim

The worst slowness is while typing in Insert mode. Typing a 7-word sentence takes 7+ seconds after VS Code has been open for a while (I think it's indirectly related to that, and other apps, taking up system memory).

I recorded a profile, and during insert mode (typing a 7-word sentence) the doGetNextEditWithSelection function takes up most of the time:

[trusktr]

Upstream issue:

• Extensions using the "type" command (for ex. Vim) have poor performance due to being single-threaded with other extensions microsoft/vscode#75627