Bug 230973

Summary:	REGRESSION (iOS 15): Using device pixel ratio degrades performance (2x lower FPS than iOS 14)
Product:	WebKit	Reporter:	tjkoury <tjkoury>
Component:	WebGL	Assignee:	Nobody <webkit-unassigned>
Status:	RESOLVED FIXED
Severity:	Normal	CC:	dino, djg, florent.masson, kbr, kkinnunen, kpiddington, webkit-bug-importer
Priority:	P2	Keywords:	InRadar
Version:	Safari Technology Preview
Hardware:	Unspecified
OS:	Unspecified
See Also:	https://bugs.webkit.org/show_bug.cgi?id=231658

Description tjkoury@gmail.com 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).

Comment 1 Radar WebKit Bug Importer 2021-09-29 15:55:10 PDT

<rdar://problem/83692664>

Comment 2 Kimmo Kinnunen 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.

Comment 3 tjkoury@gmail.com 2021-10-21 06:09:14 PDT

Any additional information required?

Comment 4 Dan Glastonbury 2022-04-11 22:38:21 PDT

Fixed in the ANGLE roll https://bugs.webkit.org/show_bug.cgi?id=238171