perf: presize node-set maps in mapNodes, ClosestNodes and winnowNodes#563
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jvoisin wants to merge 1 commit into
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perf: presize node-set maps in mapNodes, ClosestNodes and winnowNodes#563jvoisin wants to merge 1 commit into
jvoisin wants to merge 1 commit into
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Three internal helpers build a map[*html.Node]bool from a known set of nodes (or use one as a dedup accumulator over a known number of input nodes) but allocate the map without a size hint. They then incur grow-and-double rehashing as entries are inserted. Pass len(nodes) as the size hint at make time: - traversal.go mapNodes: dedup map shared by appendWithoutDuplicates across every per-node result. mapNodes is the engine behind most traversal helpers (Parents, Children, Next/Prev, Siblings, Find*, Contents, ...), so the impact is broad. - traversal.go ClosestNodes: target-node set built from nodes... - filter.go winnowNodes: large-N path's lookup set built from nodes... Double-digit performance gains across ~all benchmarks.
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Three internal helpers build a map[*html.Node]bool from a known set of nodes (or use one as a dedup accumulator over a known number of input nodes) but allocate the map without a size hint. They then incur grow-and-double rehashing as entries are inserted.
Pass len(nodes) as the size hint at make time:
Double-digit performance gains across ~all benchmarks.