Re: [frame-timing] Processing model proposal

On 3/20/15 3:59 PM, Michael Blain wrote:
> Hi Web Perf,
> Here's what we have currently. Would love to hear thoughts/comments?
> This would go in a new section of

I'd like to understand exactly what step 3 means here and what it's 
really assuming about what a "frame" is.

For example, image decoding is an async operation running on a different 
thread from JS execution.  So is layout, conceptually (and in practice 
in servo).  So is rasterization.

So for example, you could have layout start due to DOM modification from 
a timer, and more timers fire while that layout pass is still running. 
It's possible to have multiple presents to screen while that layout pass 
is running, for that matter.

In general, it seems to me like there's a mental model here of what a 
"frame" is that doesn't match all current UAs, much less future UAs, and 
it would be a good idea to clearly write down what that mental model is, 
so we can reason about it and adjust it as needed so that it does not 
overconstrain UA implementations and reflects reality in all UAs.


Received on Monday, 23 March 2015 16:01:57 UTC