3 ms·

For that last one: it's much faster in many cases, because Chrome's engine is not parallelized. Back when I was last measuring this, stylo's single-thread perf

For that last one: it's much faster in many cases, because Chrome's engine is not parallelized. Back when I was last measuring this, stylo's single-thread performance was comparable to Chrome's or a bit faster in some cases. Parallelized performance was much better. That said, actual hardware in the wild has a surprisingly low level of hardware parallelism in practice. https://data.firefox.com/dashboard/hardware https://data.firefox.com/dashboard/hardware shows that for the Firefox user base as of end of Jan 2021 54% of users had 2 cores and 34% had 4 cores.

oblio 6y ago
> That said, actual hardware in the wild has a surprisingly low level of hardware parallelism in practice. https://data.firefox.com/dashboard/hardware https://data.firefox.com/dashboard/hardware shows that for the Firefox user base as of end of Jan 2021 54% of users had 2 cores and 34% had 4 cores. True, but that's probably about to change soon. Look at the ARM stuff about to enter the arena. I wouldn't bet on us using just 2-4 cores 10 years from now. And we need to plan for that.
- bzbarsky 6y ago
  Well, right, that's why the Firefox CSS implementation actually aims to be parallelized and has been for years. I'm just saying that the wins from that on current hardware are not as large as one would hope. And that the increase in number of cores has not been increasing nearly as fast as one would like, in devices that most people actually own.
  - oblio 6y ago
    Yeah, it's a chicken and egg problem. Old software doesn't use many cores, and even new, single threaded one doesn't (Javascript, Python, Ruby, etc.). Because software doesn't really need many cores, no need to create CPUs with many, many cores. I imagine the cycle's going to break at some point, after all we can only ignore having many cores for so long. Especially that now even mobile devices routinely have at least 4 cores.
    - bzbarsky 6y ago
      Mobile devices in the field typically have _more_ cores that desktop devices. The Firefox hardware report is strongly influenced by there being a lot more desktop than mobile Firefox users. As you note, the modal number of cores on mobile has been 4-6 for a while now.
h_anna_h 6y ago
I remember reading that Chromium's engine is slower sometimes because it follows the standard more strictly. https://codeberg.org/teddit/teddit/issues/24#issuecomment-160523 https://codeberg.org/teddit/teddit/issues/24#issuecomment-16...
- bzbarsky 6y ago
  Fwiw, I've seen a number of cases of the other way around: the WebKit/Chrome CSS implementation had some shortcuts for performance reasons that caused them to not follow the spec, where Firefox did. The link you posted just indicates that Firefox rendered the page faster than Chrome; did it render it _wrong_? One other note: the linked issue here is layout, not the CSS system per se; this part is not parallelized in Gecko and is still in C++, not in Rust.

oblio 6y ago

> That said, actual hardware in the wild has a surprisingly low level of hardware parallelism in practice. https://data.firefox.com/dashboard/hardware https://data.firefox.com/dashboard/hardware shows that for the Firefox user base as of end of Jan 2021 54% of users had 2 cores and 34% had 4 cores. True, but that's probably about to change soon. Look at the ARM stuff about to enter the arena. I wouldn't bet on us using just 2-4 cores 10 years from now. And we need to plan for that.

bzbarsky 6y ago
Well, right, that's why the Firefox CSS implementation actually aims to be parallelized and has been for years. I'm just saying that the wins from that on current hardware are not as large as one would hope. And that the increase in number of cores has not been increasing nearly as fast as one would like, in devices that most people actually own.
- oblio 6y ago
  Yeah, it's a chicken and egg problem. Old software doesn't use many cores, and even new, single threaded one doesn't (Javascript, Python, Ruby, etc.). Because software doesn't really need many cores, no need to create CPUs with many, many cores. I imagine the cycle's going to break at some point, after all we can only ignore having many cores for so long. Especially that now even mobile devices routinely have at least 4 cores.
  - bzbarsky 6y ago
    Mobile devices in the field typically have _more_ cores that desktop devices. The Firefox hardware report is strongly influenced by there being a lot more desktop than mobile Firefox users. As you note, the modal number of cores on mobile has been 4-6 for a while now.

h_anna_h 6y ago

I remember reading that Chromium's engine is slower sometimes because it follows the standard more strictly. https://codeberg.org/teddit/teddit/issues/24#issuecomment-160523 https://codeberg.org/teddit/teddit/issues/24#issuecomment-16...

bzbarsky 6y ago
Fwiw, I've seen a number of cases of the other way around: the WebKit/Chrome CSS implementation had some shortcuts for performance reasons that caused them to not follow the spec, where Firefox did. The link you posted just indicates that Firefox rendered the page faster than Chrome; did it render it _wrong_? One other note: the linked issue here is layout, not the CSS system per se; this part is not parallelized in Gecko and is still in C++, not in Rust.