4 ms·

Are multiple cores being used to draw a webpage? If so, do typical webpages need this level of performance for a satisfactory user experience?

simcop2387 12y ago
Yes multiple cores are being used. It's not that typical webpages need this level of performance, but by doing this you can actually save battery life and power usage on things like mobile devices and laptops. Since you can render the page 2-3x faster (numbers pulled out of donkey) you can use a burst of more cores at a lower speed to accomplish the same thing.
- higherpurpose 12y ago
  > Since you can render the page 2-3x faster (numbers pulled out of donkey) 2-3x faster seems about right for 4 cores: http://www.phoronix.com/scan.php?page=news_item&px=MTgzNDA http://www.phoronix.com/scan.php?page=news_item&px=MTgzNDA 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). https://events.linuxfoundation.org/sites/events/files/slides/LinuxConEU2014.pdf https://events.linuxfoundation.org/sites/events/files/slides...
  - simcop2387 12y ago
    Perfect. I thought that's what I remembered reading but couldn't even come close to finding it when I wrote that. That's the kind of research they've been intending to do with it for a while now and it's honestly huge enough that I won't be too surprised if Servo starts replacing Gecko on Firefox OS and the Firefox Mobile browsers. All it's going to take is to really get it working on 90% of websites and then I think it'll be a clear contender for replacing Gecko in a lot of places. I'd love to also see a JS engine in Rust but I know with a JIT and all you end up with none of the safety you get from Rust anyway. With the browser chrome being done in HTML with the mozbrowser extensions it looks like it might be possible to start doing a lot of the same things that XUL does in firefox which opens the door to a lot of stuff being ported to the new browser.
pcwalton 12y ago
> Are multiple cores being used to draw a webpage? 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.
- smtucker 12y ago
  Do you know of any resources that go in depth into how different layouts affect parallelism?
  - pcwalton 12y ago
    I have a blog post from last year on the topic: http://pcwalton.github.io/blog/2014/02/25/revamped-parallel-layout-in-servo/ http://pcwalton.github.io/blog/2014/02/25/revamped-parallel-...
- haberman 12y ago
  It would be extremely interesting to see any numbers that compare single-core layout (in Servo) with multi-core layout (in Servo).
  - kibwen 12y ago
    Here's a draft of an experience report regarding Servo that was submitted to this year's ICFP: http://kmcallister.github.io/papers/2015-servo-experience-report-draft1.pdf http://kmcallister.github.io/papers/2015-servo-experience-re... 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 are better. Given the promising numbers here, I feel like the following bold quote from a Servo-related job opening at Mozilla is relevant: "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." http://careers.mozilla.org/en-US/position/ollA0fw0 http://careers.mozilla.org/en-US/position/ollA0fw0
ufo 12y ago
According to some tests it does help. Since the page can only "start rendering" after it finishes calculating layout so a parallel layout algorithm lets you start showing the page sooner, which may feel snappier. This is even if the page ends up taking the same amount of time to render in the end (current browsers already try to parallelize some stuff).
wmf 12y ago
do typical webpages need this level of performance for a satisfactory user experience? It's needed because low-end phones have 8 slow cores instead of 2 fast cores.
- ori_b 12y ago
  Low end phones have 1 slow core, as far as I'm aware. I'm not aware of very many 8 core phones, let alone low end ones.
  - fabrice_d 12y ago
    quad cores will be low end by the time servo is ready!
  - qznc 12y ago
    A few slow cores can do the work of one fast core in the same time with less energy. At least sometimes, depending on the parallelisation/synchronisation overhead. This is an important consideration for future mobile architectures.
  - Symmetry 12y ago
    GP meant low end smartphones. The first 64 bit android phone was one with 8 A53s coming out in China. Before that using 8 A7s was very popular. Small cores are very small compared to higher end cores. Part of this is 8 being a lucky number.
  - anonbanker 12y ago
    bought a knock-off Lenovo S850p (which is decidedly not lenovo) off Aliexpress a few months back [1]. unit legitimately has 8-cores (Mediatek 6595 Processor), and 4GB of ram. Other than the abysmal viewing angle, it's an incredible piece of hardware, especially for $100. 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. 1. http://www.aliexpress.com/item/Original-lenovo-s850c-Max-4G-RAM-MTK-Octa-Core-4G-LTE-FDD-2-5GHz-20-0MP/32288041771.html http://www.aliexpress.com/item/Original-lenovo-s850c-Max-4G-...
JohnBooty 12y ago
> If so, do typical webpages need this level of > performance for a satisfactory user experience? Servo on desktop is certainly interesting, but a primary use case is mobile devices and other devices that have multiple CPU cores that aren't very powerful individually. > draw a webpage Drawing a webpage on your screen entails a few different primary tasks. 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.

simcop2387 12y ago

Yes multiple cores are being used. It's not that typical webpages need this level of performance, but by doing this you can actually save battery life and power usage on things like mobile devices and laptops. Since you can render the page 2-3x faster (numbers pulled out of donkey) you can use a burst of more cores at a lower speed to accomplish the same thing.

higherpurpose 12y ago
> Since you can render the page 2-3x faster (numbers pulled out of donkey) 2-3x faster seems about right for 4 cores: http://www.phoronix.com/scan.php?page=news_item&px=MTgzNDA http://www.phoronix.com/scan.php?page=news_item&px=MTgzNDA 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). https://events.linuxfoundation.org/sites/events/files/slides/LinuxConEU2014.pdf https://events.linuxfoundation.org/sites/events/files/slides...
- simcop2387 12y ago
  Perfect. I thought that's what I remembered reading but couldn't even come close to finding it when I wrote that. That's the kind of research they've been intending to do with it for a while now and it's honestly huge enough that I won't be too surprised if Servo starts replacing Gecko on Firefox OS and the Firefox Mobile browsers. All it's going to take is to really get it working on 90% of websites and then I think it'll be a clear contender for replacing Gecko in a lot of places. I'd love to also see a JS engine in Rust but I know with a JIT and all you end up with none of the safety you get from Rust anyway. With the browser chrome being done in HTML with the mozbrowser extensions it looks like it might be possible to start doing a lot of the same things that XUL does in firefox which opens the door to a lot of stuff being ported to the new browser.

pcwalton 12y ago

> Are multiple cores being used to draw a webpage? 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.

smtucker 12y ago
Do you know of any resources that go in depth into how different layouts affect parallelism?
- pcwalton 12y ago
  I have a blog post from last year on the topic: http://pcwalton.github.io/blog/2014/02/25/revamped-parallel-layout-in-servo/ http://pcwalton.github.io/blog/2014/02/25/revamped-parallel-...
haberman 12y ago
It would be extremely interesting to see any numbers that compare single-core layout (in Servo) with multi-core layout (in Servo).
- kibwen 12y ago
  Here's a draft of an experience report regarding Servo that was submitted to this year's ICFP: http://kmcallister.github.io/papers/2015-servo-experience-report-draft1.pdf http://kmcallister.github.io/papers/2015-servo-experience-re... 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 are better. Given the promising numbers here, I feel like the following bold quote from a Servo-related job opening at Mozilla is relevant: "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." http://careers.mozilla.org/en-US/position/ollA0fw0 http://careers.mozilla.org/en-US/position/ollA0fw0

ufo 12y ago

According to some tests it does help. Since the page can only "start rendering" after it finishes calculating layout so a parallel layout algorithm lets you start showing the page sooner, which may feel snappier. This is even if the page ends up taking the same amount of time to render in the end (current browsers already try to parallelize some stuff).

wmf 12y ago

do typical webpages need this level of performance for a satisfactory user experience? It's needed because low-end phones have 8 slow cores instead of 2 fast cores.

ori_b 12y ago
Low end phones have 1 slow core, as far as I'm aware. I'm not aware of very many 8 core phones, let alone low end ones.
- fabrice_d 12y ago
  quad cores will be low end by the time servo is ready!
- qznc 12y ago
  A few slow cores can do the work of one fast core in the same time with less energy. At least sometimes, depending on the parallelisation/synchronisation overhead. This is an important consideration for future mobile architectures.
- Symmetry 12y ago
  GP meant low end smartphones. The first 64 bit android phone was one with 8 A53s coming out in China. Before that using 8 A7s was very popular. Small cores are very small compared to higher end cores. Part of this is 8 being a lucky number.
- anonbanker 12y ago
  bought a knock-off Lenovo S850p (which is decidedly not lenovo) off Aliexpress a few months back [1]. unit legitimately has 8-cores (Mediatek 6595 Processor), and 4GB of ram. Other than the abysmal viewing angle, it's an incredible piece of hardware, especially for $100. 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. 1. http://www.aliexpress.com/item/Original-lenovo-s850c-Max-4G-RAM-MTK-Octa-Core-4G-LTE-FDD-2-5GHz-20-0MP/32288041771.html http://www.aliexpress.com/item/Original-lenovo-s850c-Max-4G-...

JohnBooty 12y ago

> If so, do typical webpages need this level of > performance for a satisfactory user experience? Servo on desktop is certainly interesting, but a primary use case is mobile devices and other devices that have multiple CPU cores that aren't very powerful individually. > draw a webpage Drawing a webpage on your screen entails a few different primary tasks. 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.