Files
hakmem/docs/analysis
Moe Charm (CI) 6a6744d065 Phase 4 E2: Alloc Per-Class FastPath - NEUTRAL (-0.21%)
A/B Test Results (Mixed, 10-run, 20M iters):
- Baseline (DUALHOT=0): 45.40M ops/s (mean), 45.51M ops/s (median)
- Optimized (DUALHOT=1): 45.30M ops/s (mean), 45.22M ops/s (median)
- Improvement: -0.21% mean, -0.62% median

Decision: NEUTRAL (within ±1.0% noise threshold)
Action: FREEZE as research box (default OFF, no promotion)

Key Findings:
- C0-C3 fast path adds branch overhead without measurable benefit
- Unlike FREE path (+13%), ALLOC path already has optimized route caching
- Phase 3 C3 static routing eliminated route lookup overhead
- Additional per-class specialization doesn't reduce existing cost

Root Cause:
- Free DUALHOT skips expensive policy_snapshot() + tiny_route_for_class()
- Alloc DUALHOT adds C0-C3 branch but route already cached (Phase 3 C3)
- Net effect: Branch cost ≈ Route savings → neutral

Conclusion: Alloc route optimization has reached diminishing returns

Cumulative Status:
- Phase 4 E1: +3.92% (GO, research box)
- Phase 4 E2: -0.21% (NEUTRAL, frozen)

Files:
- CURRENT_TASK.md: Updated with E2 results
- docs/analysis/PHASE4_E2_ALLOC_PER_CLASS_FASTPATH_AB_TEST_RESULTS.md: Full A/B test report

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>
2025-12-14 01:54:21 +09:00
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