202269 2019-09-26 08:22:15 -0700 [iOS 13] requestAnimationFrame runs at 90Hz in low power mode 2020-08-22 16:00:57 -0700 1 1 1 Unclassified WebKit Canvas Other iPhone / iPad Other RESOLVED DUPLICATE 204713 https://bugs.webkit.org/show_bug.cgi?id=204713 https://bugs.webkit.org/show_bug.cgi?id=215745 InRadar P2 Normal --- 1 ashley webkit-unassigned beidson dino jonlee sabouhallawa simon.fraser webkit-bug-importer oldest_to_newest 1574455 0 ashley 2019-09-26 08:22:15 -0700 On iOS 13 / 13.1, requestAnimationFrame runs at 90 Hz when low power mode is enabled. Demo URL: https://www.scirra.com/labs/bugs/safari13raf/index.html Steps to reproduce: 1. Ensure low power mode is disabled 2. Visit demo URL in Safari and observe FPS reading is 60 (tested on an iPhone 7 Plus, which has a display rate of 60 Hz) 3. Go to settings and enable low power mode 4. Switch back to Safari Expected result: FPS reading either the same or dropping to 30 (as I believe previous releases did) Observed result: FPS reading is now about 90 FPS, which is higher than the display rate of the device. Originally discovered in this tweet: https://twitter.com/chribbe1/status/1176767527797579776 The issue appears to affect several web frameworks, indicating a general problem with requestAnimationFrame. I suspect a new 30 Hz timer is being set, but the old 60 Hz timer is not cancelled, resulting in adding together to make a 90 Hz callback frequency. 1574456 1 ashley 2019-09-26 08:22:52 -0700 This also defeats the purpose of low battery mode, since running rAF at 90 Hz will consume more power than 60 Hz with the setting off! 1574466 2 webkit-bug-importer 2019-09-26 08:50:55 -0700 <rdar://problem/55745055> 1610839 3 sabouhallawa 2020-01-24 13:37:08 -0800 *** This bug has been marked as a duplicate of bug 204713 ***