Hi Benoit, There's two problems that I've seen related to scrolling, and so possibly the result of APZ.
The most obvious one is that if the child process is busy doing things, then the scrollable area seems "sticky". When you start scrolling there's a noticeable delay before the page starts scrolling. My guess is that we send some message to the child process when scrolling is initiated and don't start scrolling until the child process responds (possibly with some form of timeout)? This isn't noticeable on the example page that you provided, possibly because the child process is quite responsive before we start the heavy painting operations. The other problem, which is more serious, is that every now and then the browser seems to get into a state where I can't use the trackpad at all to do scrolling. The scroll bar is displayed, as is common when using the trackpad to scroll, but no scrolling actually happens. The only way I can scroll when the browser is in this state is to hover the scrollbar and click below the scroll thumb, which enables scrolling one page at a time. The only way to get out of the state is by restarting the browser. Sadly this happens very infrequently, so I haven't been able to create steps to reproduce, nor seen any pattern in where it triggers. / Jonas On Wed, Feb 17, 2016 at 10:35 AM, Benoit Girard <bgir...@mozilla.com> wrote: > Currently APZ does not cause scrollbar initiated scrolling to be async. > I've been working in fixing this and I'd like some help testing it out > before enabling it on Nightly. If you're interested please flip > 'apz.drag.enabled' to true and restart. If you find any issue please make > it block https://bugzilla.mozilla.org/show_bug.cgi?id=1211610. > > I've got a test page here to confirm that it's turned on properly: > http://people.mozilla.org/~bgirard/scroll_no_paint.html > > Scrolling on this page is slow in FF because it hits a performance bugs in > layer construction code. However with APZ the scrolling is smooth and a bit > checkerboard-y instead. If you have 'layers.acceleration.draw-fps' set you > should notice the left most FPS counter at 60 FPS while the middle counter > will be much lower. This is APZ handling the scroll. > > Happy Testing, > Benoit > _______________________________________________ > 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
