Servo VS profiler

> Is there any easy to use/hack HTML layouting engine where I could experiment with custom CSS attributes and bridge that gap? Would anything from Servo be suitable?

Servo could be used for this. You'd want to add support for parsing the CSS properties themselves to the style crate in https://github.com/servo/stylo and then the layout implementation to the layout2020 crate in https://github.com/servo/servo. You do effectively get a whole browser though.

I'm currently working on building a lighter weight / hackable layout engine based on a combination of https://github.com/servo/stylo (for css parsing and selector resolution), https://github.com/DioxusLabs/taffy (for box-level layout) and https://github.com/pop-os/cosmic-text (for flow/inline layout). I expect to have something decent in around 6 months

Neither of these setups currently have any support for pagination though.

Great to see some competition still alive in browser engine development. See also Servo (previously part of Mozilla) https://servo.org/ - that and Ladybird are still very underdeveloped compared to every day browsers.

It's a huge shame that there are no nightly builds of ladybird to try out but I assume that's because they just don't want the bug reports (if everything doesn't work it's pointless getting random bugs filed).

I haven't messed with it yet but from looking into it, this should absolutely work.

https://github.com/servo/servo/wiki/Building-on-ARM-desktop-...

don't know, there was a downtime in 2021 and 22 but since 2023, contributions look back to where it was before .. https://github.com/servo/servo/graphs/contributors

The world has moved on though to opinionated tools, and Rust isn't even the furthest in that direction (That would be Go). The equivalent of those two lines in Cargo.toml would be this example of a basic configuration from the jacoco-maven-plugin: https://www.jacoco.org/jacoco/trunk/doc/examples/build/pom.x... - That's 40 lines in the section to do the "defaults".

Yes, you could add a load of config for files to include/exclude from coverage and so on, but the idea that that's a norm is way more common in Java projects than other languages. Like here's some example Cargo.toml files from complicated Rust projects:

Servo: https://github.com/servo/servo/blob/main/Cargo.toml

rust-gdext: https://github.com/godot-rust/gdext/blob/master/godot-core/C...

ripgrep: https://github.com/BurntSushi/ripgrep/blob/master/Cargo.toml

socketio: https://github.com/1c3t3a/rust-socketio/blob/main/socketio/C...

1. Servo

It won't don't worry. There already are forks, for the worst case scenario. And Servo is on its way. Not yet ready, but it will be. Originally, from Mozilla kitchen.

To pain broad strokes, the layout phase (~= take the HTML, take the CSS, determine the position and size of boxes) is largely sequential in production browser engine today. Selector matching (~= what CSS applies to what element) is parallel in Firefox today, via the Stylo Rust crate originally developed in the research browser engine Servo. Servo can do parallel layout in some capacity (but doesn't implement everything), https://github.com/servo/servo/wiki/Servo-Layout-Engines-Rep... is an interesting and recent document on the matter.

Parallel layout is generally considered to be a complex engineering problem by domain experts.

https://hacks.mozilla.org/2017/08/inside-a-super-fast-css-en... is a really cool article that is related, that is a few years old but what it says is largely correct today.

[Article author/submitter here]

I can only tell you that it is not what this is about, inasmuch as I was at the talk and there was not a single mention of Firefox Reality or Wolvic in the talk.

Wolvic might use Servo – but I think if it did they would mention it, right?

The talk didn't and the word "Wolvic" does not occur anywhere on https://servo.org

So I am guessing not, no.

Igalia has -- or rather is because it's a co-op -- about 100 developers. They are not all working on the same thing.

Probably your best bet is to use the Firefox Profiler once it starts hogging the CPU to try to see what it's doing. I'd be happy to take a look at the result although I don't have a lot of experience at diagnosing performance problems; hopefully the profile will make it obvious what's going on.

I tried using the https://profiler.firefox.com/ and running with:

You can try to reproduce while taking a profile using the Firefox profiler, then share it in the #perf:mozilla.org room on Mozilla's Matrix instance.

Run a profiling session for ~30 sec when you notice something is running slower than you expect, see https://profiler.firefox.com/. Share results here if you want help interpreting them.

Next time, send a SIGABRT to the main process (kill -6 $(pidof firefox)) and use the resulting backtrace (you will find a link to the crash report in about:crashes) to file a bug. A performance profile could be useful, but you'll need to know first what to capture. This seems like a graphics issue, so try the Graphics preset. Share a link to your report.

https://profiler.firefox.com will be useful if you can capture and share it to developers.

If you can reproduce it in safe mode and a clean profile, capture a performance profile using the clean profile while trying to load a problematic webpage, don't remove any information from it, and share it here (although it's typically not easy for users to analyse them), or file a bug with it attached.

Next time, capture a performance profile using the Graphics preset, and kill the browser by entering kill -6 $(pidof firefox) in a shell. This will create a bug report (unless debian disables the crash reporter) that would indicate where Firefox is stuck at. You might need to use an official build to get useful results.