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The web at maximum FPS: How WebRender gets rid of jank

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Re: The web at maximum FPS: How WebRender gets rid of jank

#31

Post by TylerE »

kibwen wrote: post #22
pohl wrote: post #13

Now that this is closer to shipping, I'm curious what impact this would have on battery life. On the one hand, this is lighting up more silicon; on the other hand: a faster race to sleep, perhaps? Have there been any measurements on what the end result is on a typical modern laptop?

Despite the huge fans and heatsinks on modern desktop GPUs, I presume that a GPU would still use less energy than a CPU for the same workload, yes? Do mobile GPUs have a sleep mode comparable to mobile CPUs? Completely agreed that some measurements would be nice.

A modern high-end GPU can draw upwards of 200w.

Edit: Not sure why I'm being downvoted for stating a simple fact. The top-of-the-line AMD and NVidia cards have TDPs of 200-250w.

Re: The web at maximum FPS: How WebRender gets rid of jank

#33

Post by pohl »

kibwen wrote: post #22
pohl wrote: post #13

Now that this is closer to shipping, I'm curious what impact this would have on battery life. On the one hand, this is lighting up more silicon; on the other hand: a faster race to sleep, perhaps? Have there been any measurements on what the end result is on a typical modern laptop?

Despite the huge fans and heatsinks on modern desktop GPUs, I presume that a GPU would still use less energy than a CPU for the same workload, yes? Do mobile GPUs have a sleep mode comparable to mobile CPUs? Completely agreed that some measurements would be nice.

The Radeon Pro 560 on my MacBook Pro can draw "up to 75W". I don't know anything about how it manages power, but I do recall that Apple recommended in a WWDC session on writing energy-efficient apps that one should be careful to not trigger the discrete GPU when the integrated Intel GPU is sufficient. So that leads to another question: on my machine, which GPU would Webrender be using? I suppose I could find out experimentally, but I thought I'd ask in case someone here knows.

Re: The web at maximum FPS: How WebRender gets rid of jank

#36

Post by epmaybe »

pohl wrote: post #33
kibwen wrote: post #22

Earlier quoted context omitted.

Despite the huge fans and heatsinks on modern desktop GPUs, I presume that a GPU would still use less energy than a CPU for the same workload, yes? Do mobile GPUs have a sleep mode comparable to mobile CPUs? Completely agreed that some measurements would be nice.

The Radeon Pro 560 on my MacBook Pro can draw "up to 75W". I don't know anything about how it manages power, but I do recall that Apple recommended in a WWDC session on writing energy-efficient apps that one should be careful to not trigger the discrete GPU when the integrated Intel GPU is sufficient. So that leads to another question: on my machine, which GPU would Webrender be using? I suppose I could find out expe…

Since the 15" MBP charger can deliver up to 87W, if you have full power draw on the MBP will you actually not be able to fully supply power over AC? I assume that the CPU also takes up around 20-30W.

Re: The web at maximum FPS: How WebRender gets rid of jank

#37

Post by nonsince »

pohl wrote: post #13

Now that this is closer to shipping, I'm curious what impact this would have on battery life. On the one hand, this is lighting up more silicon; on the other hand: a faster race to sleep, perhaps? Have there been any measurements on what the end result is on a typical modern laptop?

Your browser is doing ~60fps rendering on the GPU already, it's just doing it much less efficiently. This does less work on the CPU _and_ less work on the GPU, for the same result.

Re: The web at maximum FPS: How WebRender gets rid of jank

#38

Post by RussianCow »

nonsince wrote: post #37
pohl wrote: post #13

Now that this is closer to shipping, I'm curious what impact this would have on battery life. On the one hand, this is lighting up more silicon; on the other hand: a faster race to sleep, perhaps? Have there been any measurements on what the end result is on a typical modern laptop?

Your browser is doing ~60fps rendering on the GPU already, it's just doing it much less efficiently. This does less work on the CPU _and_ less work on the GPU, for the same result.

I don't think this is actually true. If you're looking at a static page that doesn't change in any way, isn't the browser completely idle?

Edit: To clarify, I realize that the screen gets refreshed ~60 times per second (depending on refresh rate), but I don't think any rendering actually happens if it doesn't need to.

Re: The web at maximum FPS: How WebRender gets rid of jank

#39

Post by Jasper_ »

pcwalton wrote: post #8
vvanders wrote: post #2

Good stuff. Speaking of rendering text glyphs on the GPU, there's a really clever trick(commonly called loop-blinn, from the two authors): https://developer.nvidia.com/gpugems/GPUGems3/gpugems3_ch25.... You can pretty much just use the existing bezier control points from TTF as-is which is really nice.

If only it were as simple as just using Loop-Blinn. :) The technique described there will produce unacceptably bad antialiasing for body text. Loop-Blinn is fine if you want fast rendering with medium quality antialiasing, though. (Incidentally, it's better to just use supersampling or MLAA-style antialiasing with Loop-Blinn and not try to do the fancy shader-based AA described in that article.) Additionally, the ori…

I noticed that Pathfinder went from calculating the intersection of beziers on the GPU with compute back to doing triangulation on the CPU. Any reason for this major switch in approach?

I assume you've seen other things like Slug, glyphy, etc., which use a combination of CPU pre-processing and GPU processing to make the bezier intersection as efficient as possible...

Re: The web at maximum FPS: How WebRender gets rid of jank

#40

Post by spiderfarmer »

lwansbrough wrote: post #30
pohl wrote: post #13

Now that this is closer to shipping, I'm curious what impact this would have on battery life. On the one hand, this is lighting up more silicon; on the other hand: a faster race to sleep, perhaps? Have there been any measurements on what the end result is on a typical modern laptop?

I know it’s not officially released, so I’m hoping it gets fixed, but FF57 rips through my Mac’s battery life and runs insanely hot on simple JS apps. I still use it daily because it generally works, but there are a few apps I just have to go to Chrome for.

Same here. FF has always performed poorly on my 15” 2015 rMBP, but this made it worse.
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