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Moe Charm (CI) 21e2e4ac2b Phase 4 E3-4: ENV Constructor Init (+4.75% GO)

Target: Eliminate E1 lazy init check overhead (3.22% self%)
- E1 consolidated ENV gates but lazy check remained in hot path
- Strategy: __attribute__((constructor(101))) for pre-main init

Implementation:
- ENV gate: HAKMEM_ENV_SNAPSHOT_CTOR=0/1 (default 0, research box)
- core/box/hakmem_env_snapshot_box.c: Constructor function added
  - Reads ENV before main() when CTOR=1
  - Refresh also syncs gate state for bench_profile putenv
- core/box/hakmem_env_snapshot_box.h: Dual-mode enabled check
  - CTOR=1 fast path: direct global read (no lazy branch)
  - CTOR=0 fallback: legacy lazy init (rollback safe)
  - Branch hints adjusted for default OFF baseline

A/B Test Results (Mixed, 10-run, 20M iters, E1=1):
- Baseline (CTOR=0): 44.28M ops/s (mean), 44.60M ops/s (median)
- Optimized (CTOR=1): 46.38M ops/s (mean), 46.53M ops/s (median)
- Improvement: +4.75% mean, +4.35% median

Decision: GO (+4.75% >> +0.5% threshold)
- Expected +0.5-1.5%, achieved +4.75%
- Lazy init branch overhead was larger than expected
- Action: Keep as research box (default OFF), evaluate promotion

Phase 4 Cumulative:
- E1 (ENV Snapshot): +3.92%
- E2 (Alloc Per-Class): -0.21% (NEUTRAL, frozen)
- E3-4 (Constructor Init): +4.75%
- Total Phase 4: ~+8.5%

Deliverables:
- docs/analysis/PHASE4_E3_ENV_CONSTRUCTOR_INIT_DESIGN.md
- docs/analysis/PHASE4_E3_ENV_CONSTRUCTOR_INIT_NEXT_INSTRUCTIONS.md
- docs/analysis/PHASE4_COMPREHENSIVE_STATUS_ANALYSIS.md
- docs/analysis/PHASE4_EXECUTIVE_SUMMARY.md
- scripts/verify_health_profiles.sh (sanity check script)
- CURRENT_TASK.md (E3-4 complete, next instructions)

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

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

2025-12-14 02:57:35 +09:00

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Phase 4 Status - Executive Summary

Date: 2025-12-14 Status: E1 GO（opt-in）, E2 FROZEN, E3-4 GO（opt-in） Baseline: Mixed 20M/ws=400（E1/E3-4 の ON/OFF に依存。結果は各 A/B セクション参照）

Quick Status

E2 Decision: FREEZE ✅ (NEUTRAL)

Result: -0.21% mean, -0.62% median (NEUTRAL)

Why Freeze?

Alloc route optimization saturated by Phase 3 C3 (static routing)
Free DUALHOT worked (+13%) because it skipped expensive ops
Alloc DUALHOT doesn't work (-0.21%) because route already cached
Lesson: Per-class specialization only helps when bypassing uncached overhead

Action: Keep as research box (default OFF), no further investigation

E1/E3-4 Results (Mixed A/B)

E1: ENV Snapshot Consolidation ✅ GO (opt-in)

Result: +3.92% avg, +4.01% median
ENV: HAKMEM_ENV_SNAPSHOT=1（default OFF）

E3-4: ENV Constructor Init ✅ GO (opt-in)

Result: +4.75% mean, +4.35% median（E1=1 前提）
ENV: HAKMEM_ENV_SNAPSHOT=1 HAKMEM_ENV_SNAPSHOT_CTOR=1（default OFF）

Note: “constructor での pre-main init” を効かせたい場合はプロセス起動前に ENV を設定（bench_profile putenv だけでは遅い）

Phase 4 Cumulative Status

Active:

E1 (ENV Snapshot): +3.92% ✅ GO（opt-in）
E3-4 (ENV CTOR): +4.75% ✅ GO（opt-in, requires E1）

Frozen:

D3 (Alloc Gate Shape): +0.56% ⚪
E2 (Alloc Per-Class FastPath): -0.21% ⚪

Next Actions

E3-4 の “hint/refresh” 調整後に 10-run 再確認（昇格前の最終ゲート）
GO 維持なら ENV_PROFILE_PRESETS.md と CURRENT_TASK.md に “E1+E3-4 の推奨セット” を明記
E1/E3-4 ON の状態で perf を取り直して次の芯を選ぶ（alloc gate / free_tiny_fast_cold など）

Key Lessons

Route optimization saturated: C3 already cached routes, E2 no benefit
Shape optimization plateaued: D3 +0.56% neutral, branch prediction saturated
ENV consolidation successful: E1 +3.92%, constructor init is next step
Different optimization vectors needed: Move beyond route/shape to init/dispatch overhead

Full Analysis: /mnt/workdisk/public_share/hakmem/docs/analysis/PHASE4_COMPREHENSIVE_STATUS_ANALYSIS.md

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