KarpelesLab / goro / 25772768391

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vm: pool Frame structs and their stack/locals slices

vm.Run allocated three things per call: the Frame, its stack slice
(MaxStack entries), and its locals slice (len(Locals) entries). For
recursive functions like Fibonacci that's three allocations per
recursive step.

A sync.Pool reuses the Frame and reuses its backing slices when the
next caller's MaxStack/locals dimensions fit. Slot references in the
stack are cleared at release time so the GC can reclaim ZVals; the
backing arrays survive.

BenchmarkFibonacci alloc count dropped from ~307K to ~263K per op;
wall time improved ~10%.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

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