rustdoc: Some sort of rendering optimization is needed for large source files

[tgross35]

This is a link to a source page that is ~30k lines of code, with a 2.6 MB HTML file:

https://doc.rust-lang.org/src/core/stdarch/crates/core_arch/src/aarch64/neon/generated.rs.html

On my Firefox on Windows, loading that page hangs the entire browser (other tabs) and slows down the whole OS for almost a full minute. Why this isn't better contained to a single tab I have no idea, but it seems like there is room for improvement here.

Maybe source could be rendered as plain text without colors when they exceed a complexity limit?

[tgross35]

Amusingly, firefox seems to call this ~40s paint time a bit "jank" 😄

[tgross35]

It seems like there has to be an issue for this somewhere already, but I haven't been able to find one.

[tgross35]

Hm, maybe it's a Firefox Windows bug - FF 139.0.1 loads the page without a problem on my mac.

[yotamofek]

Couldn't reproduce on FF for Windows, nor for Android (Samsung Galaxy S23 Ultra), both at version 139.0.1.
The source page loads pretty much instantly on both.

[lolbinarycat]

Unable to reproduce on Arch Linux firefox.

[tgross35]

I can't reproduce this anymore either on 139.0.4. That was a really terrible fluke then, but at least it's not on our side.