Bug 251700

Summary: DisplayList::ItemBuffer wastes a lot of vector capacity
Product: WebKit Reporter: Simon Fraser (smfr) <simon.fraser>
Component: Layout and RenderingAssignee: Simon Fraser (smfr) <simon.fraser>
Status: RESOLVED FIXED    
Severity: Normal CC: bfulgham, heycam, simon.fraser, webkit-bug-importer, wenson_hsieh, zalan
Priority: P2 Keywords: InRadar
Version: WebKit Local Build   
Hardware: Unspecified   
OS: Unspecified   
Attachments:
Description Flags
Patch none

Simon Fraser (smfr)
Reported 2023-02-03 10:29:01 PST
Using the patch in bug 186698, and testing on a wikipedia page, we see that DisplayList::ItemBuffer::ItemBuffer() wastes a lot of vector capacity: Wasted capacity: 31632 bytes (used 0 of 31632 bytes, utilization: 0.00%) - 659 allocations 1 0x2fd3346e7 WTF::VectorBuffer<WebCore::DisplayList::ItemBufferHandle, 2ul, WTF::FastMalloc>::VectorBuffer() 2 0x2fd3313d1 WebCore::DisplayList::ItemBuffer::ItemBuffer() 3 0x2fd33119c WebCore::DisplayList::DisplayList::itemBuffer() 4 0x2fd3311fe WebCore::DisplayList::DisplayList::setItemBufferWritingClient(WebCore::DisplayList::ItemBufferWritingClient*) 5 0x2fd336a1b WebCore::DisplayList::InMemoryDisplayList::InMemoryDisplayList() 6 0x2fd30735a WebCore::FontCascade::displayListForTextRun(WebCore::GraphicsContext&, WebCore::TextRun const&, unsigned int, std::__1::optional<unsigned int>, WebCore::FontCascade::CustomFontNotReadyAction) const 7 0x2fcc5efd4 WebCore::GlyphDisplayListCache::get(void const*, WebCore::FontCascade const&, WebCore::GraphicsContext&, WebCore::TextRun const&) 8 0x2fcdf55a2 WebCore::TextBoxPainter<WebCore::InlineIterator::BoxModernPath>::paintForeground(WebCore::StyledMarkedText const&) 9 0x2fcdf3efe WebCore::TextBoxPainter<WebCore::InlineIterator::BoxModernPath>::paintForegroundAndDecorations() 10 0x2fcdf3656 WebCore::TextBoxPainter<WebCore::InlineIterator::BoxModernPath>::paint() 11 0x2fc7e0b49 WebCore::LayoutIntegration::InlineContentPainter::paintDisplayBox(WebCore::InlineDisplay::Box const&) 12 0x2fc7e0db5 WebCore::LayoutIntegration::InlineContentPainter::paint() 13 0x2fc7e54a8 WebCore::LayoutIntegration::LineLayout::paint(WebCore::PaintInfo&, WebCore::LayoutPoint const&, WebCore::RenderInline const*) 14 0x2fcc96d0e WebCore::RenderBlock::paintObject(WebCore::PaintInfo&, WebCore::LayoutPoint const&)
Attachments
Patch (1.58 KB, patch)
2023-02-04 12:12 PST, Simon Fraser (smfr) 		no flags
DetailsFormatted DiffDiff
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Radar WebKit Bug Importer
Comment 1 2023-02-03 10:29:26 PST
<rdar://problem/105011333>
Simon Fraser (smfr)
Comment 2 2023-02-04 12:12:26 PST
Created attachment 464837 [details] Patch
EWS
Comment 3 2023-02-04 17:07:17 PST
Committed 259861@main (b7a8c3d2ff89): <https://commits.webkit.org/259861@main> All reviewed patches have been landed. Closing bug and clearing flags on attachment 464837 [details].
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