Yes. There is coarse-grained parallelism (e.g. script, layout, painting can all happen simultaneously) and fine-grained parallelism (e.g. every render object is restyled and laid out concurrently).
> If so, do typical webpages need this level of performance for a satisfactory user experience?
It depends on the site, of course, but preliminary results show that multicore style recalc and layout result in large improvements in many areas that feel slow today. Examples are loading new items on "infinite-scroll" pages and CSS transitions that require layout (e.g. "top", "left", "margin-right"). In particular, Web developers frequently write animations that require layout, so large improvements there have the potential to benefit apps a lot.
And as a Firefox fanboy, I'm sad to report that Firefox is on the latter end of the continuum. What you describe is my experience exactly -- except that it's not quite limited to mobile.
I do all my primary development against Firefox. I'm content to optimize for Gecko, and I've learned what it handles well and what it doesn't . In cases where I've really doubled down to optimize some transitions, I can get almost-butter from Firefox, where Chrome and Safari are pure pleasure, seemingly no matter what I throw at them. Hell, even IE 11 is better when it comes to transitions.
That said, I think Gecko looks the most beautiful for static rendering. This is less true since Chrome 38, which supports proper web font rendering for Windows, but I'll maintain that Gecko's compositor output still has a certain je ne sais quoi compared to everything else.
Still, as a developer who "wants the web to win,"  it's troubling to me that the vendors with native platforms are still outperforming in the browser space, and I hope that Servo is the dark horse that will change all that.
 For instance, I've read this thread one too many times: https://bugzilla.mozilla.org/show_bug.cgi?id=524925
 Quoting http://jlongster.com/Radical-Statements-about-the-Mobile-Web
Table 1 seems to give some relevant data:
Site | Gecko | Servo 1 thread | Servo 4 threads
Reddit | 250 | 100 | 55
CNN | 105 | 50 | 35
Table 1. Performance of Servo against Mozilla's Gecko
rendering engine on the layout portion of some common
sites. Times are in milliseconds, where lower numbers
"Our goal is nothing less than building the fastest and most secure browser engine, and we aim to succeed by miles, not inches. We aim for double the performance of current engines, with no crashes."
It's needed because low-end phones have 8 slow cores instead of 2 fast cores.
I install Xiaomi's latest MIUI on them (and Play Store), and then resell them locally for $300 each. and people tell me they're stealing them from me at that price.
> If so, do typical webpages need this level of
> performance for a satisfactory user experience?
> draw a webpage
Some things like alpha blending and animation can be offloaded to the GPU quite well and this is already being done extensively today on various mobile OSs.
Other things like layout, DOM manipulation, and scripting involve a lot of branching logic and need to be handled by the CPU. That's where Servo comes in - the goal is to better spread that stuff out across multiple CPU cores.
2-3x faster seems about right for 4 cores:
I think that was on 4 ARM cores/threads, so the increase in performance may be even bigger for 4 cores/8 thread chips.
From the PDF link it also seems that if the 4 cores work "at the same performance" level as 1 core, power consumption can drop down to 40% (page 23).
Sounds interesting. Do you have more information on that? Any links?
IIRC its built with Rust and maybe some unsafe C/C++ code (unsafe in terms of Rust) for things such as the JS engine.
More info about Rust at http://www.rust-lang.org/
More info about Servo at https://github.com/servo/servo#the-servo-parallel-browser-pr...
And you don't need to be a Rust expert to contribute (not least because essentially nobody in the world fits that description)! It's totally common for initial commits to be the first serious lines of Rust a contributor has ever written ( https://twitter.com/chimeracoder/status/583755185899626496 ).
I remember asking for advice years ago where to cut my teeth on C++ and getting suggested WebKit by several — and people who weren't trying to lead me massively into a pit of doom. (Admittedly, I've still practically never contributed to WebKit, and I ended up doing my first larger bits of C++ on Presto. But hey, I've still read plenty of WebKit code over the years.)
I'll attribute this to a couple of things:
We actively maintain a list of [easy bugs](https://github.com/servo/servo/labels/E-easy). This also means holding off on fixing minor things. For example, if I'm working on a feature I might notice some things which can be fixed, or have some portions of the feature that are easy to implement but can be excluded from the main pull request without losing out on much. I'll file E-Easy issues and land the basic pr, and those small changes will be something a hopeful new contributor can pick up and work on. Resisting that itch to fix all the things gets us a good crop of easy bugs. We don't have many string substitution easy bugs unlike projects like Firefox, but most of the easy bugs can be worked on in an hour or two given a Servo build and basic Rust knowledge. Usually less than that.
Additionally, we do easy bugs right. There's almost always enough information to help a newbie get started; with links to the relevant code and/or spec. Of course, there's a lot we can improve on here, but we're still ahead of the curve on this.
We also mentor newbies -- if you leave a comment on an issue asking for help (or drop in on IRC), someone's bound to help you.
We consciously consider newbie onboarding, too -- "will this affect newbies?" is a common issue that springs up in discussions. It helps that many of the core contributors (including me) are volunteers themselves.
Our code generally isn't too complicated. Most of the areas which newbies flock to (eg the DOM) are well documented and we don't have much usage of advanced, confusing looking Rust features. I've seen open source code heavy with template metaprogramming and all sorts of strange macros --- whilst our code does use macros and syntax extensions, it looks pretty clean and to the most part the strangeness is innocuous (eg the annotations and other strangeness look ignorable). To be fair, this is probably highly subjective, but to me Rust code is generally quite readable, even when it uses advanced features -- it was this way when I started, too.
Also, we have Josh :) He is behind most of the mentoring system in Firefox and is in general very interested in easing the way for new contributors -- most of the stuff above probably was largely his initiative. If you want ideas on how to improve newbie onboarding on a project you're interesting, you might want to have a discussion with him (or Ms2ger) in IRC.
: I'm really fond of such bugs because they make for a very smooth transition for those trying out open source. For the first bug you do some easy thing like editing a string or deleting a comment or renaming a function, and get used to the version control system, issue tracker, and the workflow. For the second bug, try something more substantial; you can focus on the code this time without worrying about other things.
There's probably still time for this. We could create a nightly distribution of Servo in a day or so; but at the moment I don't think we see a need of this, especially given that there are still a couple of things (like everything needed for jQuery support) which we should get working first so that sites actually work in Servo. Perhaps this quarter we'll get all these features done.
(FWIW we have a nightly android apk distribution, but at the moment it's broken due to openssl strangeness)
I like these competition jokes :)
That wasn't intentionally a joke (I wrote that bit), but I can see how it sounds like one. "chrome" is a term for the stuff that's part of a browser but not the browser engine (the rest of the UI).
I did realize that that term could be misinterpreted (damn you Google) and thoought of alternative ways of putting it, but I couldn't come up with anything. "GUI" and "shell" both sounded wrong.
When I said "another" I was referring to MiniServo and the CEF port.