Bug 186739

Summary:	StyleResolver wastes 224KB of HashTable capacity on nytimes.com
Product:	WebKit	Reporter:	Simon Fraser (smfr) <simon.fraser>
Component:	CSS	Assignee:	Nobody <webkit-unassigned>
Status:	NEW ---
Severity:	Normal	CC:	koivisto, simon.fraser, webkit-bug-importer
Priority:	P2	Keywords:	InRadar
Version:	WebKit Nightly Build
Hardware:	Unspecified
OS:	Unspecified

Description Simon Fraser (smfr) 2018-06-16 12:40:16 PDT

Using tooling from bug 186698, loading can and running "notifyutil -p com.apple.WebKit.dumpHashTableCapacity" shows:

Wasted capacity: 224128 bytes (used 113280 of 337408 bytes, utilization: 33.57%) - 14 allocations
1   0x107578105 WTF::HashTable<unsigned int, WTF::KeyValuePair<unsigned int, WebCore::StyleResolver::MatchedPropertiesCacheItem>, WTF::KeyValuePairKeyExtractor<WTF::KeyValuePair<unsigned int, WebCore::StyleResolver::MatchedPropertiesCacheItem> >, WTF::IntHash<unsigned int>, WTF::HashMap<unsigned int, WebCore::StyleResolver::MatchedPropertiesCacheItem, WTF::IntHash<unsigned int>, WTF::HashTraits<unsigned int>, WTF::HashTraits<WebCore::StyleResolver::MatchedPropertiesCacheItem> >::KeyValuePairTraits, WTF::HashTraits<unsigned int> >::HashTable()
2   0x1075780e5 WTF::HashMap<unsigned int, WebCore::StyleResolver::MatchedPropertiesCacheItem, WTF::IntHash<unsigned int>, WTF::HashTraits<unsigned int>, WTF::HashTraits<WebCore::StyleResolver::MatchedPropertiesCacheItem> >::HashMap()
3   0x10754ed35 WTF::HashMap<unsigned int, WebCore::StyleResolver::MatchedPropertiesCacheItem, WTF::IntHash<unsigned int>, WTF::HashTraits<unsigned int>, WTF::HashTraits<WebCore::StyleResolver::MatchedPropertiesCacheItem> >::HashMap()
4   0x10754e645 WebCore::StyleResolver::StyleResolver(WebCore::Document&)
5   0x10754fdfd WebCore::StyleResolver::StyleResolver(WebCore::Document&)
6   0x108b9af17 WebCore::Style::Scope::resolver()
7   0x108ba1ad1 WebCore::Style::TreeResolver::Scope::Scope(WebCore::Document&)
8   0x108ba1b8d WebCore::Style::TreeResolver::Scope::Scope(WebCore::Document&)

Comment 1 Radar WebKit Bug Importer 2018-06-16 12:40:46 PDT

<rdar://problem/41189264>