Here is a time trace for enwiki:Barack_Obama with the --replay option to eliminate I/O effects. See the onExtLink handler performance which looks like an outlier for what should be a trivial and fast transformation. This is not specific to the BO page and can be seen across a number of pages
-------------------------------------------------------
Recorded times (in ms) for sync token transformations
-------------------------------------------------------
TOTAL PARSE TIME: 11477
TOTAL PROFILED TIME: 8226
DOMPasses:TOP: 2043
ExtensionHandler:onExtension: 1210; count: 584; per-instance: 2.07192
HTML5 TreeBuilder: 1054
DOMPasses:NESTED: 1014
SyncTTM: 527
PEG: 344
AsyncTTM (Partial): 343
ExternalLinkHandler:onExtLink: 302; count: 903; per-instance: 0.33444
SanitizerHandler:onAny: 254; count: 41515; per-instance: 0.00612
buildDOMFragment: 238; count: 2296; per-instance: 0.10366
WikiLinkHandler:onWikiLink: 197; count: 2828; per-instance: 0.06966
AttributeExpander:onToken: 168; count: 70875; per-instance: 0.00237
TemplateHandler:onTemplate: 114; count: 696; per-instance: 0.16379
Setup Environment: 114
TokenStreamPatcher:onAny: 55; count: 37261; per-instance: 0.00148
ParagraphWrapper:onAny: 54; count: 19932; per-instance: 0.00271
QuoteTransformer:onAny: 23; count: 10121; per-instance: 0.00227
OnlyInclude:onAnyInclude: 23; count: 25360; per-instance: 0.00091
PreHandler:onAny: 22; count: 2035; per-instance: 0.01081
ListHandler:onAny: 21; count: 13864; per-instance: 0.00151
QuoteTransformer:onQuote: 20; count: 1274; per-instance: 0.0157
ListHandler:onListItem: 18; count: 1460; per-instance: 0.01233
QuoteTransformer:processQuotes: 14; count: 341; per-instance: 0.04106
PreHandler:onNewline: 14; count: 2062; per-instance: 0.00679
Pre-parse (source fetch): 9
QuoteTransformer:processQuotes:end: 9; count: 290; per-instance: 0.03103
ListHandler:onEnd: 7; count: 667; per-instance: 0.01049
ExternalLinkHandler:onUrlLink: 4; count: 1; per-instance: 4
ParagraphWrapper:onEnd: 4; count: 1; per-instance: 4
TokenStreamPatcher:onEnd: 2; count: 667; per-instance: 0.003
BehaviorSwitchHandler:onBehaviorSwitch: 2; count: 1; per-instance: 2
ParagraphWrapper:onNewLine: 2; count: 2062; per-instance: 0.00097
TokenStreamPatcher:onNewline: 1; count: 2308; per-instance: 0.00043
ExternalLinkHandler:onEnd: 0; count: 1355; per-instance: 0
-------------------------------------------------------