1943848 - Testcase generating 150K custome elements (with Shadow DOM)

Status: RESOLVED WORKSFORME

(Core :: DOM: Core & HTML, enhancement)

Description

[Mayank Bansal]

Attachment: custom elements - shadow DOM.HTML

Open attached testcase
Enter 5000. Click generate

Nightly: https://share.firefox.dev/4hy2WPp (45s)
Chrome: https://share.firefox.dev/42vkfMN (10s)

I suspect that the large time in Nightly is all in reflow for this testcase, and not necessarily generating custom elements.

Testcase was generated using chatpgpt.

Comment 1

[Emilio Cobos Álvarez [:emilio]]

That's just because we're extending <video> and <audio>, would be better to ignore those because of bug 1943629. With those removed it's probably better

Comment 2

[Mayank Bansal]

Attachment: custom elements - shadow DOM_NO AV.HTML

Same testcase as above, without audio and video.

150000 elements
Nightly: https://share.firefox.dev/4jy227t (16s)
Chrome: Couldnt capture profile

Reload: https://share.firefox.dev/40LYgjz
Delete elements: https://share.firefox.dev/42tu8dS

Comment 3

[Mayank Bansal]

For the second testcase:
N=300000
Firefox: https://share.firefox.dev/44BvD9E (7s in DOM, 5s in Style, rest in layout)
Chrome: https://share.firefox.dev/44pHVBI

this bug focusses on DOM and maybe style perf. I think we are much better than Chrome here.
Closing this as WFM.