Terminal canvas renderer can be slow sometimes

[dzg]

Issue Type: Performance Issue

Since a few days ago VS Code is EXTREMELY sluggish, to the point of not being useable.
I tried disabling ALL extensions (except builtin) but did not help.
I also deleted all support files/folders in ~/Library. Did not help.

This is even with just 1 single editor open.

Help!!!
UPDATE After some testing, it seems to happen when I open a terminal panel in VS Code. If I close the terminal panel, it returns to normal speed.

VS Code version: Code 1.33.1 (51b0b28, 2019-04-11T08:22:55.268Z)
OS version: Darwin x64 15.6.0

System Info

Item	Value
CPUs	Intel(R) Core(TM) i7-4790K CPU @ 4.00GHz (8 x 4000)
GPU Status	2d_canvas: unavailable_software checker_imaging: disabled_off flash_3d: enabled flash_stage3d: enabled flash_stage3d_baseline: enabled gpu_compositing: enabled multiple_raster_threads: enabled_on native_gpu_memory_buffers: enabled rasterization: unavailable_off surface_synchronization: enabled_on video_decode: enabled webgl: enabled webgl2: enabled
Load (avg)	4, 4, 4
Memory (System)	32.00GB (14.88GB free)
Process Argv
Screen Reader	no
VM	0%

Process Info

CPU %	Mem MB	   PID	Process
   14	    98	  2545	code main
    0	    66	  2546	   gpu-process
    0	   492	  2547	   window (fox-server2.js — portal (Workspace))
    0	     0	  2573	     /bin/bash -l
    0	    98	  2601	     extensionHost
    0	   131	  2608	       electron_node tsserver.js 
    0	    66	  2621	         electron_node typingsInstaller.js typesMap.js 
    0	    66	  2665	       /Users/dang/Applications/Visual Studio Code.app/Contents/Frameworks/Code Helper.app/Contents/MacOS/Code Helper /Users/dang/Applications/Visual Studio Code.app/Contents/Resources/app/extensions/json-language-features/server/dist/jsonServerMain --node-ipc --clientProcessId=2601
    0	    33	  2602	     watcherService
    0	    33	  2692	     /Users/dang/Applications/Visual Studio Code.app/Contents/Frameworks/Code Helper.app/Contents/MacOS/Code Helper /Users/dang/Applications/Visual Studio Code.app/Contents/Resources/app/out/bootstrap-fork ms-vscode.node2 {"common.vscodemachineid":"18c4dcf0f0ffbc117ed7b3bcba62025922b56fc996bd3556cbaacb019f69358e","common.vscodesessionid":"7689dc4a-a274-4861-b55f-447b3bedd3e21555577571247"} AIF-d9b70cd4-b9f9-4d70-929b-a071c400b217
    0	    66	  2618	   shared-process
    0	    98	  2802	   window (Issue Reporter)
    0	     0	  2806	   /bin/ps -ax -o pid=,ppid=,pcpu=,pmem=,command=

Workspace Info

|  Window (fox-server2.js — portal (Workspace))
|    Folder (portal): 3033 files
|      File types: js(2382) html(401) css(94) png(52) json(51) DS_Store(24)
|                  jsx(9) vue(6) txt(4) gitignore(2)
|      Conf files: package.json(3) launch.json(1);

Extensions: none

[Antisunny]

Have you compare the loading speed of native Terminal.app and VScode Terminal panel?

[dzg]

Have you compare the loading speed of native Terminal.app and VScode Terminal panel?

Yes, normal Terminal is "normal" speed. If I close the terminal panel, VSC returns to normal speed.

Note that it's not just the terminal panel in VSC that is slow ... it's the entire app, including any editor panels.

I noticed same behavior on 3 separate machines.

[koenpunt]

I see extreme slowness without having a terminal panel open. For now I downgraded to 1.32.3, and disabled auto update to make VSCode usable again.

[Tyriar]

@dzg does this setting fix the problem?

"terminal.integrated.rendererType": "dom"

See https://github.com/Microsoft/vscode/wiki/Performance-Issues for diagnosing performance issues.

[dzg]

@dzg does this setting fix the problem?

"terminal.integrated.rendererType": "dom"

Yes, seems that it does! Thanks!

[Tyriar]

You're probably hitting one of the issues that the canvas renderer just can't handle very well, such as:

• GPU doesn't like rendering Chromium's canvas
• Chromium disables GPU acceleration
• The terminal renders lots of colors, particularly in background
• The terminal renders lots of non-ascii characters

The workaround for this is to use the DOM renderer, which typically will degrade performance in some focuses cases, but it should have better overall performance:

"terminal.integrated.rendererType": "dom"

The end fix here is to bring xterm.js' WebGL renderer into VS Code xtermjs/xterm.js#2033

[clankill3r]

Even when I set it to dom it is still unbearable slow. (this is with colors etc.).
I estimate around 10fps.

This is what scrolling in 1987 looked like:
https://www.youtube.com/watch?v=L41oIvre9K0

[Tyriar]

@clankill3r the DOM being too slow for a huge highly dynamic buffer is exactly why I pursued the canvas implementation, but there are issues with a 2d rendering context that we simply cannot overcome without going lower level which is why I put together the WebGL renderer.

Since your hardware seems to have issues with both, you can try it out if you want and let me know if it solves the perf issue. To try it out clone the xterm.js repo, launch the demo and hit the Enable WebGL Renderer button down the bottom: https://github.com/xtermjs/xterm.js/wiki/Contributing#linux-or-macos

[Tyriar]

This isn't actionable outside of electron updates improving GPU support, new hardware or xtermjs/xterm.js#2033

[vscodebot]

Thanks for creating this issue! We figured it's covering the same as another one we already have. Thus, we closed this one as a duplicate. You can search for existing issues here. See also our issue reporting guidelines.

Happy Coding!