Jittery cursor motion related to performance

[Peluko]

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BUG REPORT

Environment:

• VSCode Version: 1.12.1
• VsCodeVim Version: 0.7.1
• OS: Windows 10

What happened:

Motion by keeping pressed a key is jittery with random back jumps. For example, I've recorded the motion while scrolling a file from bottom to top. At the start of the video I press and hold cursor up key and I don't release it until the end of the video:

This happens with any motion command (cursor keys, hjkl, ebw...). Note the last jump, from line 1 to line 50 and then back to line 1 and jump again to line 48.

This effect is somewhat related to performance. It happens when the CPU has some work load. I've observed that it;s only noticeable when global CPU load is over 50/60%, more noticeable as the CPU load increases. Disabling VSCodeVim and moving with cursor keys works fine even when CPU is at 100% (not very responsive due to cpu load, but no jittering).

While scrolling with VsCodeVim enabled, I can see two VSCode processes with 20/25% CPU load each one. While scrolling with VsCodeVim disabled, VSCode only goes to 10/15% CPU.

I've observed this behaviour also on OSX.

[jpoon]

Sounds similar to #1154. Can you try https://github.com/VSCodeVim/Vim#mac-setup and see if that helps?

[xconverge]

I dont think mac-setup will help, especially since he is on windows ;)

@johnfn I suspect the task queue still, I really do... I have seen this type of behavior every once in awhile still as well

[Peluko]

No, mac-setup definitely won't work for Windows 10 ;)

[Chillee]

I've been looking at this issue intermittently, and I suspect that this piece of code might be the cause (the issue is related too): #1340 (comment)

[Peluko]

During the last weeks I've noticed that I didn't had any problem with this issue. Code is running smoothly with VSCodeVim enabled. I was curious and looking for what might have changed during this time I've found this: #1842
Well this could have been the cause for all my problems, as they have vanished now.

Closing this issue.

[Chillee]

Very possible. I'm very sorry that we made such a stupid mistake that screwed up our performance so badly :p