Fifth serialize-path pass (#139, docs/benchmarks.md pass 31). textNeedsEscaping,
attributeNeedsEscaping, and the comment/processingInstruction existence checks
run unconditionally on every text node, attribute value, comment, and PI in a
document, scanning through UTF8View's default Collection iteration. Profiling
a new deeply-nested, attribute-dense corpus (the standard flat catalog corpus
has no density to indict this) put the two needsEscaping functions as the
largest PureXML-specific frames in the sample. A standalone micro-benchmark
confirmed withContiguousStorageIfAvailable's raw buffer scan measures ~2-2.75x
faster than the Collection-based scan, with a Collection fallback kept for a
non-contiguous (foreign/bridged) string.
Two abstraction attempts were tried and rejected before landing this shape: a
shared generic helper taking a predicate closure recovered most but not all of
the win, and calling a separate small function from inside the buffer loop (to
dodge a cyclomatic-complexity violation) erased nearly the entire win even
though it isn't a closure value. The violation is instead resolved by splitting
each function into a contiguous/collection pair, moving the call boundary
outside the loop rather than inside it.
Output is byte-identical by construction; full local suite (1925 tests) and
full lint unchanged. Measured with interleaved same-state A/B under real
concurrent machine load: clean with zero overlap across 5 pairs at the nested
corpus (~9%), noisier at the standard corpus but the means still separate
clearly (~4%).
Mihaela Mihaljevic
fb9dab2028