Perf Improvement Ideas for `DomBackend`

[benoitlx]

Note: I will edit this post further in the future

Ideas

• use textContent instead of innerHtml for modifying cell content (textContent does not parse html and is not prone to xss attacks)
• defining common style classes and disable/enable them on cell depending of new content style
• Batch update of new content using fragment ?

Metrics to test

• fps
• surely more

Let me know if you have any though on this !

[orhun]

Thanks for creating this issue! I think making these changes overall would be great.

One unrelated question that has been lingering in my mind is, should we support some way of controlling the FPS? Right now everything renders at the highest FPS possible and I'm afraid this might not be optimal for all the uses cases out there (e.g. games)

[junkdog]

Ideas

could all be worth looking into. i don't think any of it has been explored before.

Metrics to test

i took a screenshot of one profiled frame. it takes about 60ms for ratzilla to do its thing. most of the time is spent in the dombackend. since a lot of cells are replaced, this triggers a re-layout (~16ms). i don't understand why the "Paint" task is so slow at almost two frames. (maybe textContent can help with this?).

the yellow stuff under "Layout" is the GC - not sure if this is from the old html or all the string allocations.

One unrelated question that has been lingering in my mind is, should we support some way of controlling the FPS?

could maybe cap it at e.g. 30 or 60, as a simple way of limiting cpu usage w/o any other underlying changes to the app.

(e.g. games)

hmm, the only way i could see this happening if the game internally uses ms resolution, but then runs on a 244hz display - could possibly mess up some of the math esp if updates don't happen on a fixed time-step, but in practice i don't think it's a problem. most games are structured around some for of game loop which can deal with variable delta time.

capping at a preset fps is a pretty easy way of limiting cpu usage - worst case scenario, 244hz means 4x more cpu compared to a 60hz displays.