Created attachment 675854 [details] about support.txt User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:19.0) Gecko/19.0 Firefox/19.0 Build ID: 20121027030611 Steps to reproduce: 1. enable debug paint flashing. 2. Disable HWA 3. go to : http://grssam.com/ 4. Scroll down/up 5. See the psychedelic world! Actual results: Constant repaints. If possible, check CPU usage during scrolling. Hits 80% usage on my system. For a simple page, CPU usage shouldnt be this high. Expected results: minimal repainting. With HWA on, the repainting is minimal. Also made a note of this on Taras' blog here : https://blog.mozilla.org/tglek/2012/10/26/snappy-42/#comments
with further testing, this is reproducible only when both 1. HWA off AND 2. layers.acceleration.disabled = false.
Summary: with HWA off, constant invalidation on http://grssam.com/ while scrolling → with HWA off and layers acceleration enabled, constant invalidation on http://grssam.com/ while scrolling
This also causes 100% CPU usage. Profiler link : http://people.mozilla.com/~bgirard/cleopatra/?report=da6f29d78630bd41b1f3a67cbf3eeffb0d74167a BoxBlurVertical and BoxBlurHorizontal are present a lot in the profile.
Summary: with HWA off and layers acceleration enabled, constant invalidation on http://grssam.com/ while scrolling → constant full page invalidation on http://grssam.com/ while scrolling with HWA off
HWA ON : http://people.mozilla.com/~bgirard/cleopatra/#report=ccd2502f490fb9acf05ab07566ac8a8cb53916e4&mergeUnbranched=true&invertCallback=true&selection=%255B%2522(total)%2522%252C%2522NtUserPeekMessage%2522%255D HWA OFF : http://people.mozilla.com/~bgirard/cleopatra/#report=dbbae9a4418c37323cdd0e7ad573d820955f877f&mergeUnbranched=true&invertCallback=true With HWA OFF, 1. Full page invalidation while scrolling 2.AlphaBoxBlur increases to 10% of profile. In HWA on, its hardly 2%.
So after more testing, i found that a specific element on the page causes the invalidation. The element is the floating "back to top" button that appears on the page when you scroll a little. If you use Adblockplus to hide this element, there will be no invalidation. Better STR : 1. Disable HWA 2. Go to http://grssam.com/ 3. Scroll down a bit. Stop scrolling. 4. A floating button labeled "back to top" will appear on the bottom of the screen. 5. Now start scrolling again. 6. There will be full page invalidation.
Summary: constant full page invalidation on http://grssam.com/ while scrolling with HWA off → Floating button on http://grssam.com/ causes full page invalidation
Also happens here : http://www.asstr.org/files/Collections/nifty/gay/encounters/backpack-to-europe (NSFW)
Summary: Floating button on http://grssam.com/ causes full page invalidation → Floating button causes full page invalidation
We do get a whole page invalidation on scrolling with layers disabled on the original URL, which is weird because I didn't think we changed invalidation or layerisation depedning on the layers backend.
Status: UNCONFIRMED → NEW
Ever confirmed: true
Created attachment 690698 [details] [diff] [review] Use the best active scrolled root, even if it isn't a parent of everything I can't see any reason why this wouldn't work, fixes this page. It also stops us from choosing a new active scrolled root when we recurse into ProcessDisplayItems for a clip.
Attachment #690698 - Flags: review?(roc)
Attachment #690698 - Flags: review?(roc) → review+
Status: NEW → RESOLVED
Last Resolved: 6 years ago
Resolution: --- → FIXED
Target Milestone: --- → mozilla20
Comment on attachment 690698 [details] [diff] [review] Use the best active scrolled root, even if it isn't a parent of everything [Approval Request Comment] Bug caused by (feature/regressing bug #): 810302 User impact if declined: Loss of cleartype in some cases (bug 828206) Testing completed (on m-c, etc.): more than 6 weeks on central Risk to taking this patch (and alternatives if risky): pretty low risk given the exposure already String or UUID changes made by this patch: none
Attachment #690698 - Flags: approval-mozilla-beta?
Comment on attachment 690698 [details] [diff] [review] Use the best active scrolled root, even if it isn't a parent of everything We have heard a lot of users reporting this in 18.0 & approving the low risk fix for beta to get this fixed in Fx 19 timeframe
Attachment #690698 - Flags: approval-mozilla-beta? → approval-mozilla-beta+
Assignee: nobody → matt.woodrow
status-firefox19: --- → fixed
status-firefox20: --- → fixed
I confirm this fix is verified on FF 19b3 on Windows 7 x64. Mozilla/5.0 (Windows NT 6.1; WOW64; rv:19.0) Gecko/20100101 Firefox/19.0(20130123083802)
I confirm the fix is verified on FF 20.b1 too following STR from Comment 0: Mozilla/5.0 (Windows NT 6.1; rv:20.0) Gecko/20100101 Firefox/20.0
Status: RESOLVED → VERIFIED
status-firefox19: fixed → verified
status-firefox20: fixed → verified
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