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Vansh Verma
← Lab

reclaim

confirmedshipRust · Apple M4Systems & data structuresJuly 14, 2026

the question

How do epoch-based reclamation and hazard pointers trade retained memory against per-operation fence cost on M4?

what came out

Under one stalled thread, EBR retained nodes equal the number of retires (unbounded) while hazard pointers stay flat at O(T*H+batch), at most 144. The hazard-pointer guarded read costs 0.510 ns versus 0.329 ns for EBR, a 1.55x CI-separated fence tax that buys the bounded-memory guarantee. Neither scheme dominates.

method & receipts

  • Result: confirmed
  • Pre-registered — the prediction was written down and committed before the run.
  • Reproducible — one script re-runs the whole thing from scratch.
  • Tested — a correctness/benchmark suite ships alongside the code.

→ read the code and re-run it

github.com/v-code01/reclaim