Phase 14 v1: Pointer-Chase Reduction (tcache) NEUTRAL (+0.20%)

Implementation:
- Intrusive LIFO tcache layer (L1) before UnifiedCache
- TLS per-class bins (head pointer + count)
- Intrusive next pointers (via tiny_next_store/load SSOT)
- Cap: 64 blocks per class (default)
- ENV: HAKMEM_TINY_TCACHE=0/1 (default: 0, OFF)

A/B Test Results (Mixed 10-run):
- Baseline (TCACHE=0): 51,083,379 ops/s
- Optimized (TCACHE=1): 51,186,838 ops/s
- Mean delta: +0.20% (below +1.0% GO threshold)
- Median delta: +0.59%

Verdict: NEUTRAL - Freeze as research box (default OFF)

Root Cause (v1 wiring incomplete):
- Free side pushes to tcache via unified_cache_push()
- Alloc hot path (tiny_hot_alloc_fast) doesn't consume tcache
- tcache becomes "sink" without alloc-side pop → ROI not measurable

Files:
- Created: core/box/tiny_tcache_{env_box,box}.h, tiny_tcache_env_box.c
- Modified: core/front/tiny_unified_cache.h (integration)
- Modified: core/bench_profile.h (refresh sync)
- Modified: Makefile (build integration)
- Results: docs/analysis/PHASE14_POINTER_CHASE_REDUCTION_1_AB_TEST_RESULTS.md
- v2 Instructions: docs/analysis/PHASE14_POINTER_CHASE_REDUCTION_2_NEXT_INSTRUCTIONS.md

Next: Phase 14 v2 (connect tcache to tiny_front_hot_box alloc/free hot path)

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

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

docs/analysis/PHASE14_POINTER_CHASE_REDUCTION_1_DESIGN.md

@@ -147,3 +147,12 @@ GO/NO-GO:
 - tcache hit 率が高い場合、配列アクセス・FIFO の古い再利用を回避できる
 - “system malloc が速い” の差分（tcache 的挙動）に寄せる最短の一手
 
+---
+
+## Update（2025-12-15）
+
+v1 の統合点（`core/front/tiny_unified_cache.h`）だけでは、現行の main alloc hot path（`tiny_hot_alloc_fast()`）が tcache を消費しないため、
+`HAKMEM_TINY_TCACHE=1` のとき tcache が “sink” になりやすい。
+
+次は hot path（`core/box/tiny_front_hot_box.h`）へ pop/push を接続して、通電した状態で再 A/B を取る（Phase 14 v2）:
+- `docs/analysis/PHASE14_POINTER_CHASE_REDUCTION_2_NEXT_INSTRUCTIONS.md`