Bug 220827 – Slow layout and high CPU usage when visiting a web page (slow SVG filters)

• Status: NEW
• Component: Layout and Rendering

When visiting this page: https://ninjarockstar.dev/css-hex-grids/ and scroll down, the content shows up slowly (need to wait a few seconds) and a high CPU usage of the process is observed during rendering the content.

Tried Chrome and Firefox on the same machine, and they don't have the same slow issue.

I agree that the CSS is complicated on this page but it might be something that worths to look into if other browsers do not have the same issue. Your help is much appreciated.

[Simon Fraser (smfr)]

    +               !       : |         +       !     :   7464 WebCore::RenderLayer::paintLayerContents(WebCore::GraphicsContext&, WebCore::RenderLayer::LayerPaintingInfo const&, WTF::OptionSet<WebCore::RenderLayer::PaintLayerFlag>)  (in WebCore) + 8901  [0x7d1e564a5]
    +               !       : |         +       !     :     7464 WebCore::RenderLayer::paintLayerContents(WebCore::GraphicsContext&, WebCore::RenderLayer::LayerPaintingInfo const&, WTF::OptionSet<WebCore::RenderLayer::PaintLayerFlag>)  (in WebCore) + 8901  [0x7d1e564a5]
    +               !       : |         +       !     :       7262 WebCore::RenderLayer::paintLayerContents(WebCore::GraphicsContext&, WebCore::RenderLayer::LayerPaintingInfo const&, WTF::OptionSet<WebCore::RenderLayer::PaintLayerFlag>)  (in WebCore) + 10360  [0x7d1e56a58]
    +               !       : |         +       !     :       | 5319 WebCore::FEDropShadow::platformApplySoftware()  (in WebCore) + 980  [0x7d1c9bb44]
    +               !       : |         +       !     :       | + 5319 WebCore::ShadowBlur::blurLayerImage(unsigned char*, WebCore::IntSize const&, int)  (in WebCore) + 1185,2626,...  [0x7d00a94d1,0x7d00a9a72,...]
    +               !       : |         +       !     :       | 470 WebCore::FEDropShadow::platformApplySoftware()  (in WebCore) + 1136  [0x7d1c9bbe0]
    +               !       : |         +       !     :       | + 469 WebCore::GraphicsContext::fillRect(WebCore::FloatRect const&, WebCore::Color const&)  (in WebCore) + 526  [0x7d1c3919e]
    +               !       : |         +       !     :       | + ! 469 CGContextFillRect  (in CoreGraphics) + 105  [0x7fff3100a35b]
    +               !       : |         +       !     :       | + !   469 CGContextFillRects  (in CoreGraphics) + 96  [0x7fff3100a3c2]

[Radar WebKit Bug Importer]

<rdar://problem/73477917>

[[e-mail]]

I think I encountered this bug too, on this page:

https://goodtimerauktion.ch/de/auctions

Gnome Web 45.0 takes over 30s to finish drawing the page. Scrolling seems to block the UI thread for a few seconds. Safari on MacOS and IOS seem to be affected too.