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7 Commits

Author SHA1 Message Date
Moe Charm (CI)
8052e8b320 Phase 24-26: Hot path atomic telemetry prune (+2.00% cumulative) 
Summary:
- Phase 24 (alloc stats): +0.93% GO
- Phase 25 (free stats): +1.07% GO
- Phase 26 (diagnostics): -0.33% NEUTRAL (code cleanliness)
- Total: 11 atomics compiled-out, +2.00% improvement

Phase 24: OBSERVE tax prune (tiny_class_stats_box.h)
- Added HAKMEM_TINY_CLASS_STATS_COMPILED (default: 0)
- Wrapped 5 stats functions: uc_miss, warm_hit, shared_lock, tls_carve_*
- Result: +0.93% (baseline 56.675M vs compiled-in 56.151M ops/s)

Phase 25: Tiny free stats prune (tiny_superslab_free.inc.h)
- Added HAKMEM_TINY_FREE_STATS_COMPILED (default: 0)
- Wrapped g_free_ss_enter atomic in free hot path
- Result: +1.07% (baseline 57.017M vs compiled-in 56.415M ops/s)

Phase 26: Hot path diagnostic atomics prune
- Added 5 compile gates for low-frequency error counters:
  - HAKMEM_TINY_C7_FREE_COUNT_COMPILED
  - HAKMEM_TINY_HDR_MISMATCH_LOG_COMPILED
  - HAKMEM_TINY_HDR_META_MISMATCH_COMPILED
  - HAKMEM_TINY_METRIC_BAD_CLASS_COMPILED
  - HAKMEM_TINY_HDR_META_FAST_COMPILED
- Result: -0.33% NEUTRAL (within noise, kept for cleanliness)

Alignment with mimalloc principles:
- "No atomics on hot path" - telemetry moved to compile-time opt-in
- Fixed per-op tax elimination
- Production builds: maximum performance (atomics compiled-out)
- Research builds: full diagnostics (COMPILED=1)

Generated with Claude Code
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Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>
 2025-12-16 05:35:11 +09:00
Moe Charm (CI)
cbb35ee27f Phase 13 v1 + E5-2 retest: Both NEUTRAL, freeze as research boxes 
Phase 13 v1: Header Write Elimination (C7 preserve header)
- Verdict: NEUTRAL (+0.78%)
- Implementation: HAKMEM_TINY_C7_PRESERVE_HEADER ENV gate (default OFF)
- Makes C7 nextptr offset conditional (0→1 when enabled)
- 4-point matrix A/B test results:
  * Case A (baseline): 51.49M ops/s
  * Case B (WRITE_ONCE=1): 52.07M ops/s (+1.13%)
  * Case C (C7_PRESERVE=1): 51.36M ops/s (-0.26%)
  * Case D (both): 51.89M ops/s (+0.78% NEUTRAL)
- Action: Freeze as research box (default OFF, manual opt-in)

Phase 5 E5-2: Header Write-Once retest (promotion test)
- Verdict: NEUTRAL (+0.54%)
- Motivation: Phase 13 Case B showed +1.13%, re-tested with dedicated 20-run
- Results (20-run):
  * Case A (baseline): 51.10M ops/s
  * Case B (WRITE_ONCE=1): 51.37M ops/s (+0.54%)
- Previous test: +0.45% (consistent with NEUTRAL)
- Action: Keep as research box (default OFF, manual opt-in)

Key findings:
- Header write tax optimization shows consistent NEUTRAL results
- Neither Phase 13 v1 nor E5-2 reaches GO threshold (+1.0%)
- Both implemented as reversible ENV gates for future research

Files changed:
- New: core/box/tiny_c7_preserve_header_env_box.{c,h}
- Modified: core/box/tiny_layout_box.h (C7 offset conditional)
- Modified: core/tiny_nextptr.h, core/box/tiny_header_box.h (comments)
- Modified: core/bench_profile.h (refresh sync)
- Modified: Makefile (add new .o files)
- Modified: scripts/run_mixed_10_cleanenv.sh (add C7_PRESERVE ENV)
- Docs: PHASE13_*, PHASE5_E5_2_HEADER_WRITE_ONCE_* (design/results)

Next: Phase 14 (Pointer-chase reduction, tcache-style intrusive LIFO)

🤖 Generated with Claude Code

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>
 2025-12-15 00:32:25 +09:00
Moe Charm (CI)
ea221d057a Phase 6: promote Front FastLane (default ON) 2025-12-14 16:28:23 +09:00
Moe Charm (CI)
f7b18aaf13 Phase 5 E5-2: Header Write-Once (NEUTRAL, FROZEN) 
Target: tiny_region_id_write_header (3.35% self%)
- Hypothesis: Headers redundant for reused blocks
- Strategy: Write headers ONCE at refill boundary, skip in hot alloc

Implementation:
- ENV gate: HAKMEM_TINY_HEADER_WRITE_ONCE=0/1 (default 0)
- core/box/tiny_header_write_once_env_box.h: ENV gate
- core/box/tiny_header_write_once_stats_box.h: Stats counters
- core/box/tiny_header_box.h: Added tiny_header_finalize_alloc()
- core/front/tiny_unified_cache.c: Prefill at 3 refill sites
- core/box/tiny_front_hot_box.h: Use finalize function

A/B Test Results (Mixed, 10-run, 20M iters):
- Baseline (WRITE_ONCE=0): 44.22M ops/s (mean), 44.53M ops/s (median)
- Optimized (WRITE_ONCE=1): 44.42M ops/s (mean), 44.36M ops/s (median)
- Improvement: +0.45% mean, -0.38% median

Decision: NEUTRAL (within ±1.0% threshold)
- Action: FREEZE as research box (default OFF, do not promote)

Root Cause Analysis:
- Header writes are NOT redundant - existing code writes only when needed
- Branch overhead (~4 cycles) cancels savings (~3-5 cycles)
- perf self% ≠ optimization ROI (3.35% target → +0.45% gain)

Key Lessons:
1. Verify assumptions before optimizing (inspect code paths)
2. Hot spot self% measures time IN function, not savings from REMOVING it
3. Branch overhead matters (even "simple" checks add cycles)

Positive Outcome:
- StdDev reduced 50% (0.96M → 0.48M) - more stable performance

Health Check: PASS (all profiles)

Next Candidates:
- free_tiny_fast_cold: 7.14% self%
- unified_cache_push: 3.39% self%
- hakmem_env_snapshot_enabled: 2.97% self%

Deliverables:
- docs/analysis/PHASE5_E5_2_HEADER_REFILL_ONCE_DESIGN.md
- docs/analysis/PHASE5_E5_2_HEADER_REFILL_ONCE_AB_TEST_RESULTS.md
- CURRENT_TASK.md (E5-2 complete, FROZEN)

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

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>
 2025-12-14 06:22:25 +09:00
Moe Charm (CI)
d54893ea1d Phase 3 C3: Static Routing A/B Test ADOPT (+2.20% Mixed gain) 
Step 2 & 3 Complete:
- A/B test (Mixed 10-run): STATIC_ROUTE=0 (38.91M) → =1 (39.77M) = +2.20% avg
  - Median gain: +1.98%
  - Result: ✅ GO (exceeds +1.0% threshold)

- Decision: ✅ ADOPT into MIXED_TINYV3_C7_SAFE preset
  - bench_profile.h line 77: HAKMEM_TINY_STATIC_ROUTE=1 default
  - Learner auto-disables static route when HAKMEM_SMALL_LEARNER_V7_ENABLED=1

Implementation Summary:
- core/box/tiny_static_route_box.{h,c}: Research box (Step 1A)
- core/front/malloc_tiny_fast.h: Route lookup integration (Step 1B, lines 249-256)
- core/bench_profile.h: Bench sync + preset adoption

Cumulative Phase 2-3 Gains:
- B3 (Routing shape): +2.89%
- B4 (Wrapper split): +1.47%
- C3 (Static routing): +2.20%
- Total: ~6.8% (35.2M → ~39.8M ops/s)

Next: Phase 3 C1 (TLS Prefetch, expected +2-4%)

🤖 Generated with Claude Code

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>
 2025-12-13 18:46:11 +09:00
Moe Charm (CI)
a6aeeb7a4e Phase 1 Refactoring Complete: Box-based Logic Consolidation ✅ 
Summary:
- Task 1.1 ✅: Created tiny_layout_box.h for centralized class/header definitions
- Task 1.2 ✅: Updated tiny_nextptr.h to use layout Box (bitmasking optimization)
- Task 1.3 ✅: Enhanced ptr_conversion_box.h with Phantom Types support
- Task 1.4 ✅: Implemented test_phantom.c for Debug-mode type checking

Verification Results (by Task Agent):
- Box Pattern Compliance: ⭐⭐⭐⭐⭐ (5/5) - MISSION/DESIGN documented
- Type Safety: ⭐⭐⭐⭐⭐ (5/5) - Phantom Types working as designed
- Test Coverage: ⭐⭐⭐☆☆ (3/5) - Compile-time tests OK, runtime tests planned
- Performance: 0 bytes, 0 cycles overhead in Release build
- Build Status: ✅ Success (526KB libhakmem.so, zero warnings)

Key Achievements:
1. Single Source of Truth principle fully implemented
2. Circular dependency eliminated (layout→header→nextptr→conversion)
3. Release build: 100% inlining, zero overhead
4. Debug build: Full type checking with Phantom Types
5. HAK_RET_ALLOC macro migrated to Box API

Known Issues (unrelated to Phase 1):
- TLS_SLL_HDR_RESET from sh8bench (existing, will be resolved in Phase 2)

Next Steps:
- Phase 2 readiness: ✅ READY
- Recommended: Create migration guide + runtime test suite
- Alignment guarantee will be addressed in Phase 2 (Headerless layout)

🤖 Generated with Claude Code + Gemini (implementation) + Task Agent (verification)

Co-Authored-By: Gemini <gemini@example.com>
Co-Authored-By: Claude <noreply@anthropic.com>
 2025-12-03 11:38:11 +09:00
Moe Charm (CI)
6e2552e654 Bugfix: Add Header Box and fix Class 0/7 header handling (crash rate -50%) 
Root Cause Analysis:
- tls_sll_box.h had hardcoded `class_idx != 7` checks
- This incorrectly assumed only C7 uses offset=0
- But C0 (8B) also uses offset=0 (header overwritten by next pointer)
- Result: C0 blocks had corrupted headers in TLS SLL → crash

Architecture Fix: Header Box (Single Source of Truth)
- Created core/box/tiny_header_box.h
- Encapsulates "which classes preserve headers" logic
- Delegates to tiny_nextptr.h (0x7E bitmask: C0=0, C1-C6=1, C7=0)
- API:
  * tiny_class_preserves_header() - C1-C6 only
  * tiny_header_write_if_preserved() - Conditional write
  * tiny_header_validate() - Conditional validation
  * tiny_header_write_for_alloc() - Unconditional (alloc path)

Bug Fixes (6 locations):
- tls_sll_box.h:366 - push header restore (C1-C6 only; skip C0/C7)
- tls_sll_box.h:560 - pop header validate (C1-C6 only; skip C0/C7)
- tls_sll_box.h:700 - splice header restore head (C1-C6 only)
- tls_sll_box.h:722 - splice header restore next (C1-C6 only)
- carve_push_box.c:198 - freelist→TLS SLL header restore
- hakmem_tiny_free.inc:78 - drain freelist header restore

Impact:
- Before: 23.8% crash rate (bench_random_mixed_hakmem)
- After: 12% crash rate
- Improvement: 49.6% reduction in crashes
- Test: 88/100 runs successful (vs 76/100 before)

Design Principles:
- Eliminates hardcoded class_idx checks (class_idx != 7)
- Single Source of Truth (tiny_nextptr.h → Header Box)
- Type-safe API prevents future bugs
- Future: Add lint to forbid direct header manipulation

Remaining Work:
- 12% crash rate still exists (likely different root cause)
- Next: Investigate with core dump analysis

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

Co-Authored-By: Claude <noreply@anthropic.com>
 2025-11-29 07:57:49 +09:00