230973 2021-09-29 11:53:49 -0700 REGRESSION (iOS 15): Using device pixel ratio degrades performance (2x lower FPS than iOS 14) 2022-04-11 22:38:21 -0700 1 1 1 Unclassified WebKit WebGL Safari Technology Preview Unspecified Unspecified RESOLVED FIXED https://bugs.webkit.org/show_bug.cgi?id=231658 InRadar P2 Normal --- 1 tjkoury webkit-unassigned dino djg florent.masson kbr kkinnunen kpiddington webkit-bug-importer oldest_to_newest 1798481 0 tjkoury 2021-09-29 11:53:49 -0700 The Cesium library (https://cesium.com)performance is halved when using the devicePixelRatio for canvas resolution. These app: https://celestrak.com/cesium/orbit-viz.php?tle=/pub/TLE/catalog.txt&satcat=/pub/satcat.txt&referenceFrame=1 runs at 35fps on Chrome 93.0.4577.63 (64-bit), Pop!_OS 20.10 & Windows 10, iPhone 12 Pro Max (iOS 14), iPad 2020 (iOS 14). Updated this morning on iPhone & iPad, immediate 50% reduction in performance (~17 fps). 1798637 1 webkit-bug-importer 2021-09-29 15:55:10 -0700 <rdar://problem/83692664> 1803663 2 kkinnunen 2021-10-13 00:30:24 -0700 Thanks for the report. I can repro that the app is definitively smoother on iOS 14 than iOS 15. 1807106 3 tjkoury 2021-10-21 06:09:14 -0700 Any additional information required? 1860563 4 djg 2022-04-11 22:38:21 -0700 Fixed in the ANGLE roll https://bugs.webkit.org/show_bug.cgi?id=238171