That's a good idea. Filed bug 1092320.
On Fri, Oct 31, 2014 at 3:48 PM, Ehsan Akhgari <ehsan.akhg...@gmail.com> wrote: > Can we make sure to log something to the web console when we choose to > dishonor will-change? That will help web developers to be able to reason > about why will-change doesn't give them the performance benefits that they > expect. > > > On 2014-10-31 3:36 PM, Benoit Girard wrote: >> >> Yes, it's implemented in part 1-4 of my patch queue in bug 961871. >> >> Here's how it works -but is subject to change at any time-: >> - The following are all in untransformed CSS pixel unit. This makes >> the implementation *much* simpler[1] and more predicable for web >> authors[2]. >> - We look at the scrollport area (the bounds of the visible area) of >> the document that will-change is used within to set the budget. This >> is multiplied by some constant which is currently 3 times but I'll >> open a discussion to change that to perhaps as high as 9 times within >> the Firefox 36 time-frame. >> - When a frame is seen that uses will-change the area of the frame is >> added to the budget for that document. >> - If the total usage for that document is in budget then all >> will-change optimizations are performed. Otherwise none are performed. >> >> [1] We need to decide the will-change budget at the end of the display >> list phase which is too early to know the will-change costs in layer >> pixel which happens in the follow layer building phase. Using CSS >> pixels prevents us from requiring a second pass in some cases to >> properly implement the will-change budget in terms of layer pixels. >> [2] If layer pixel were used an author could lose their will-change >> optimizations because we decided to re-rasterize a scaled layer at a >> higher resolution. This happens seemingly unpredictably from an >> author' point of view. >> >> >> On Fri, Oct 31, 2014 at 3:10 PM, L. David Baron <dba...@dbaron.org> wrote: >>> >>> On Friday 2014-10-31 14:17 -0400, Benoit Girard wrote: >>>> >>>> As of next week I intend to turn will-change on by default on all >>>> platform. It has been developed behind the >>>> layout.css.will-change.enabled;true preference since Firefox 31 and >>>> has been enabled for certified FirefoxOS apps since 1.4[1] [2]. Blink >>>> has already shipped this [3], IE lists the feature as >>>> 'under-consideration [4] with 163 votes [5]. >>> >>> >>> Have we implemented protections to deal with overuse of will-change >>> (e.g., just ignoring all will-change uses in a document that uses it >>> too much, for some definition of too much)? >>> >>> -David >>> >>> -- >>> 𝄞 L. David Baron http://dbaron.org/ 𝄂 >>> 𝄢 Mozilla https://www.mozilla.org/ 𝄂 >>> Before I built a wall I'd ask to know >>> What I was walling in or walling out, >>> And to whom I was like to give offense. >>> - Robert Frost, Mending Wall (1914) >> >> _______________________________________________ >> dev-platform mailing list >> dev-platform@lists.mozilla.org >> https://lists.mozilla.org/listinfo/dev-platform >> > _______________________________________________ dev-platform mailing list dev-platform@lists.mozilla.org https://lists.mozilla.org/listinfo/dev-platform
