Collect expansion analysis tables in hashes and sort them once at the end#842
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Collect expansion analysis tables in hashes and sort them once at the end#842jackfirth wants to merge 1 commit into
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… end `source-analyze` accumulated visited and context syntax objects in mutable sorted maps keyed by syntax path. Expansion writes to those tables far more often than anything reads from them: every observed visit event records the visited form plus every original subform within it, and expansion visits nested forms repeatedly, so the same paths get written many times over. Each write ran `syntax-path<=>` a logarithmic number of times, which made red-black tree lookups the single largest cost in analysis. Only two places need the tables in sorted order, and both run after expansion has finished, so the tables can be plain hashes that get sorted once at the end. This cuts analysis time for `xrepl-lib/xrepl/xrepl.rkt` (1877 lines) from ~78 seconds to ~44 seconds. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
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source-analyzeaccumulated visited and context syntax objects in mutable sorted maps keyed by syntax path. Expansion writes to those tables far more often than anything reads from them — every visit event records the visited form plus every original subform inside it, and expansion visits nested forms repeatedly — so the same paths get written over and over, each write runningsyntax-path<=>a logarithmic number of times. Red-black tree lookups came out as the single largest cost in analysis.Only two places need sorted order, and both run after expansion finishes, so the tables can be plain hashes that get sorted once at the end. This takes analysis of
xrepl-lib/xrepl/xrepl.rkt(1877 lines) from ~71s to ~45s.raco test -p resyntaxpasses.This overlaps with #840 — both attack the cost of
syntax-path<=>, so their speedups don't add. Together they come to ~36s.Found by profiling, in the same vein as #800.
Measurement note: figures are the minimum of 3 runs after a warmup. An earlier version of this description said ~78s → ~44s; that baseline was taken on a thermally throttled machine and overstated the ratio. Repeated runs on identical code vary by up to ~6% here, so treat differences smaller than that as unresolved.