Bug 182436 – animation-play-state: paused causes very high cpu load because of style invalidation loop

• Status: RESOLVED
• Resolution: FIXED
• Component: Animations

[Steffen Deusch]

Hello everyone,
when using animation-play-state: paused on an animated element and using a transition on a parent element, Safari, Safari TP and WebKit Nightly are suddenly recalculating styles all the time, causing a high cpu load. Opening the Web Inspector causes an even higher CPU load (using WebKit Nightly):

https://files.steffend.me/public/webkitbug/webkit-style-invalidation.html
Try to open the page in Safari and hover over the card. Then open the Web Inspector.
The same is happening in MobileSafari on iOS 11.2(.x), causing the battery to drain fast.

Next, try opening:
https://files.steffend.me/public/webkitbug/webkit-style-invalidation-playing.html
There, the issue doesn't happen, as the animation is not paused (also no high cpu usage in the Web Inspector).

[Radar WebKit Bug Importer]

<rdar://problem/37182562>

[Antti Koivisto]

Created attachment 340325 [details]
patch

[WebKit Commit Bot]

Comment on attachment 340325 [details]
patch

Clearing flags on attachment: 340325

Committed r231794: <https://trac.webkit.org/changeset/231794>

[WebKit Commit Bot]

All reviewed patches have been landed.  Closing bug.