hakmem

Files

Moe Charm (CI) d0b931b197 Phase 3 C1: TLS Prefetch Implementation - NEUTRAL Result (Research Box)

Step 1 & 2 Complete:
- Implemented: core/front/malloc_tiny_fast.h prefetch (lines 264-267, 331-334)
  - LEGACY path prefetch of g_unified_cache[class_idx] to L1
  - ENV gate: HAKMEM_TINY_PREFETCH=0/1 (default OFF)
  - Conditional: only when prefetch enabled + route_kind == LEGACY

- A/B test (Mixed 10-run): PREFETCH=0 (39.33M) → =1 (39.20M) = -0.34% avg
  - Median: +1.28% (within ±1.0% neutral range)
  - Result: 🔬 NEUTRAL (research box, default OFF)

Decision: FREEZE as research box
- Average -0.34% suggests prefetch overhead > benefit
- Prefetch timing too late (after route_kind selection)
- TLS cache access is already fast (head/tail indices)
- Actual memory wait happens at slots[] array access (after prefetch)

Technical Learning:
- Prefetch effectiveness depends on L1 miss rate at access time
- Inserting prefetch after route selection may be too late
- Future approach: move prefetch earlier or use different target

Next: Phase 3 C2 (Metadata Cache Optimization, expected +5-10%)

🤖 Generated with Claude Code

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

2025-12-13 19:01:57 +09:00

ATOMIC_FREELIST_INDEX.md

ENV cleanup: Remove BG/HotMag vars & guard fprintf (Larson 52.3M ops/s)

2025-11-26 14:45:26 +09:00

CONFIGURATION.md

P0 Optimization: Shared Pool fast path with O(1) metadata lookup

2025-12-04 16:21:54 +09:00

CURRENT_SPEC.md

Debug Counters Implementation - Clean History

2025-11-05 12:31:14 +09:00

DOCS_INDEX.md

WIP: Add TLS SLL validation and SuperSlab registry fallback