[webkit-dev] setTimeout as browser speed throttle

[David Hyatt]

On Sep 30, 2008, at 3:41 PM, Peter Kasting wrote:

> On Tue, Sep 30, 2008 at 1:35 PM, Brady Eidson <beidson at apple.com>  
> wrote:
> If we add a new well specified API that all browser vendors agree  
> on, everybody wins.
>
> No; everybody who's willing and able to change wins.
>
> Everyone else wins or loses depending on whether the new behavior is  
> better or worse for them.  My argument is that this makes life  
> better for nearly all pages affected.  The entire reason to change  
> setTimeout() is precisely _because_ not everyone will change their  
> web pages.
>
> (Furthermore, I claim the number of people who will realize they  
> could get something better, and change their code to get it, is  
> lower than the number of people who will see that something is wrong  
> and fix it.)
>
> negates the need to introduce new incompatibilities into the already  
> published web by changing setTimeout().
>
> This still implies there is a meaningful compatibility hit to making  
> this change.  I have not yet seen any reason to agree that is the  
> case (in the sense of "CPU usage is not a web compatibility  
> issue").  There is _already_ no compatibility here.  Browsers do  
> completely different things, of an equivalent magnitude (6 ms) to  
> the suggested change of 10 ms -> 3 or 4 ms.  Firefox is even  
> different based on whether Flash happens to be running!  How can  
> there be compatibility problems introduced by this proposal that  
> don't already exist?
>

This is purely theoretical (as I said before, I think lowering the  
clamp value is reasonable), but one could imagine JS games that have a  
"reasonable" speed variance because of current browser clamps.  In  
other words the game remains playable because of the reasonable clamp  
limits.  Going from 10ms to 1ms is a gigantic boost in "frame rate"  
for a naively coded game that is just using 0 timeouts.  Lowering to  
1ms could cause the game to become so fast that it would no longer be  
playable.

As someone said before, the difference between 10ms and 15ms is not a  
wide variance compared to 10ms and 1ms.

dave
(hyatt at apple.com)

-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.webkit.org/pipermail/webkit-dev/attachments/20080930/26ddf2f9/attachment.html