Performance regression with maximized window on 2.0.0-canary.9

• I am on the latest Hyper.app version
• I have searched the issues of this repo and believe that this is not a duplicate

• OS version and name: macOS Sierra (10.12.6 (16G29))
• Hyper.app version: 2.0.0-canary.9

Issue

We have a huge perf regression with xterm3 with a big/maximized window (using vi for example)

xterm2 (2.0.0-canary.8)

xterm3 (2.0.0-canary.9)

Performance recording with xterm3

Try with last 1.8.2-beta.3 Electron version and no change.

I have same performance issue with VSCode

cc @Tyriar

[bgw]

@Tyriar I need an ordered map implementation for the LRU cache, so I’m relying on the ES6 Map implementation, which guarantees insertion order iteration. We’ll either need to pull in a polyfill, or I’ll need to write a minimal ordered map implementation myself. Alternatively, we can try relying on the iteration order of objects in JS, but that’s also a fairly new addition to the spec, though every major browser does implement it.

Regarding the space characters: I use powerline, and that screenshot is from the demo page which doesn’t use the right font, so I’m guessing it’s just a couple of characters that didn’t render quite right.

The diff isn’t ready for review yet, I just wanted to let people know that I’m working on it, so that nobody else starts to work on the same thing.

[bgw]

FYI: Even with the dynamic char atlas patch set, drawing characters with a background is slower than without, since we make a new call to fillRect for each character (even when adjacent characters are the same color), which ends up being expensive (it takes up nearly half the render time for me).

I’m hoping to tackle that problem next, but you might still want to stick with the :hi Normal ctermbg=none hack for now.

EDIT: Oh, and let me know if you encounter any issues with the new atlas!