radixevict

null resultshipPython · CPUInference & servingJuly 12, 2026

the question

Does the subtree-closed (leaf-only) eviction constraint in radix prefix caches cost hit rate versus unrestricted eviction?

what came out

No, contrary to the pre-registered prediction that it strictly costs. The leaf-only offline optimum equals the unrestricted optimum on all 2592 instances, and leaf-only LRU makes identical decisions to a sane unconstrained LRU on all 93312 instances (its interior evictions are only timestamp ties). The constraint is free offline and neutral online.

method & receipts

Result: null result — an honest negative, reported as it came out.
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/radixevict