On Thu, Sep 20, 2018 at 7:25 AM smaug <sm...@welho.com> wrote: > On 09/20/2018 04:21 PM, Mike Hommey wrote: > > On Thu, Sep 20, 2018 at 12:18:49PM +0300, smaug wrote: > >> On 09/19/2018 08:34 PM, Nicholas Alexander wrote: > >>> 2. > >>> > >>> Making the main browser window be an HTML document with (mostly) > HTML > >>> DOM elements instead of a XUL document with (mostly) XUL DOM > elements. > >> > >> It is still mystery to me how the performance can be anywhere close to > XUL when > >> starting browser or opening a new window. > >> XUL's prototype cache was explicitly added because of performance long > ago. > >> That is why we need to only load already parsed document in a binary > format, > >> or in case of new window, just clone from the prototype. > >> Last time I heard, moving to use HTML document does cause significant > regressions. > > > > I'm reminded of https://bugzilla.mozilla.org/show_bug.cgi?id=618912 but > > IIRC there were similar experiments back then on desktop, and basic html > > chrome was significantly faster than basic xul chrome. > That bug seems to be more about the layout. > > > https://screenshotscdn.firefoxusercontent.com/images/d1753829-3ebd-4c42-a757-14757051accf.png > is > the latest numbers I've seen. That isn't pgo, so may or many not be very > accurate, but the regression is > very significant. >
I'm not expert in these areas, so I hope the experts chime in, but I think there are lots of trade offs here. I believe that you are correct: the XUL prototype cache and similar mechanisms significantly impact browser startup and related metrics. But there is a general belief, which I do not have references for, that the HTML widget set is either faster than or will be faster than the XUL widget set. Certainly folks believe that effort should be put into optimizing core Web Platform technologies (rather than Mozilla-specific extensions). In any case, I do not personally know enough to put the regressions you're highlighting into context, so I'll leave that for others. Let me leave with an honest question: why can't we do the equivalent of the XUL prototype cache for the browser HTML document window? Best, Nick _______________________________________________ dev-platform mailing list dev-platform@lists.mozilla.org https://lists.mozilla.org/listinfo/dev-platform
