RESOLVED FIXED 230973
REGRESSION (iOS 15): Using device pixel ratio degrades performance (2x lower FPS than iOS 14) 
https://bugs.webkit.org/show_bug.cgi?id=230973
Summary REGRESSION (iOS 15): Using device pixel ratio degrades performance (2x lower ...
tjkoury@gmail.com
Reported 2021-09-29 11:53:49 PDT
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).
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Radar WebKit Bug Importer
Comment 1 2021-09-29 15:55:10 PDT
<rdar://problem/83692664>
Kimmo Kinnunen
Comment 2 2021-10-13 00:30:24 PDT
Thanks for the report. I can repro that the app is definitively smoother on iOS 14 than iOS 15.
tjkoury@gmail.com
Comment 3 2021-10-21 06:09:14 PDT
Any additional information required?
Dan Glastonbury
Comment 4 2022-04-11 22:38:21 PDT
Fixed in the ANGLE roll https://bugs.webkit.org/show_bug.cgi?id=238171
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