jolt/jolt-core at feat/reduce-acc-sroa - simon/jolt

simon/jolt

History

Yogthos e2598280fe DO NOT MERGE — reduce-acc SROA regresses (defeats vec-reduce) Reduce-accumulator scalar replacement: lower (reduce (fn [acc x] body) (->Rec inits) coll) with a non-escaping record accumulator to a loop carrying the acc fields as scalar vars. Correct (run-reduce-sroa.ss 7/7, make test + shakesmoke green) but a PERF REGRESSION: ray tracer hit-all 38.4s -> ~53s. Root cause: jolt's reduce already iterates a vector with vec-reduce (seq.ss) — a tight index loop over the backing store, zero per-element allocation. Lowering to a (seq)/(first)/(next) loop allocates a seq node per element, trading hit-all's CONDITIONAL ->HitAcc allocation for a per-element seq allocation. The targeted accumulator allocation is also conditional (only on hit improvement), not the dominant per-sphere cost. Kept on this branch for reference; not merged.	2026-06-26 11:28:34 -04:00
..
clojure/core	Fixed-arity protocol dispatch shims (#223 )	2026-06-26 05:57:42 +00:00
jolt	DO NOT MERGE — reduce-acc SROA regresses (defeats vec-reduce)	2026-06-26 11:28:34 -04:00

Yogthos e2598280fe DO NOT MERGE — reduce-acc SROA regresses (defeats vec-reduce)

Reduce-accumulator scalar replacement: lower (reduce (fn [acc x] body) (->Rec
inits) coll) with a non-escaping record accumulator to a loop carrying the acc
fields as scalar vars. Correct (run-reduce-sroa.ss 7/7, make test + shakesmoke
green) but a PERF REGRESSION: ray tracer hit-all 38.4s -> ~53s.

Root cause: jolt's reduce already iterates a vector with vec-reduce (seq.ss) — a
tight index loop over the backing store, zero per-element allocation. Lowering to
a (seq)/(first)/(next) loop allocates a seq node per element, trading hit-all's
CONDITIONAL ->HitAcc allocation for a per-element seq allocation. The targeted
accumulator allocation is also conditional (only on hit improvement), not the
dominant per-sphere cost. Kept on this branch for reference; not merged.

2026-06-26 11:28:34 -04:00

clojure/core

Fixed-arity protocol dispatch shims (#223 )

2026-06-26 05:57:42 +00:00

jolt

DO NOT MERGE — reduce-acc SROA regresses (defeats vec-reduce)

2026-06-26 11:28:34 -04:00