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Author SHA1 Message Date
Moe Charm (CI)
89a9212700 Phase 83-1 + Allocator Comparison: Switch dispatch fixed (NO-GO +0.32%), PROFILE correction, SCORECARD update 
Key changes:
- Phase 83-1: Switch dispatch fixed mode (tiny_inline_slots_switch_dispatch_fixed_box) - NO-GO (marginal +0.32%, branch reduction negligible)
  Reason: lazy-init pattern already optimal, Phase 78-1 pattern shows diminishing returns

- Allocator comparison baseline update (10-run SSOT, WS=400, ITERS=20M):
  tcmalloc: 115.26M (92.33% of mimalloc)
  jemalloc: 97.39M (77.96% of mimalloc)
  system: 85.20M (68.24% of mimalloc)
  mimalloc: 124.82M (baseline)

- hakmem PROFILE correction: scripts/run_mixed_10_cleanenv.sh + run_allocator_quick_matrix.sh
  PROFILE explicitly set to MIXED_TINYV3_C7_SAFE for hakmem measurements
  Result: baseline stabilized to 55.53M (44.46% of mimalloc)
  Previous unstable measurement (35.57M) was due to profile leak

- Documentation:
  * PERFORMANCE_TARGETS_SCORECARD.md: Reference allocators + M1/M2 milestone status
  * PHASE83_1_SWITCH_DISPATCH_FIXED_RESULTS.md: Phase 83-1 analysis (NO-GO)
  * ALLOCATOR_COMPARISON_QUICK_RUNBOOK.md: Quick comparison procedure
  * ALLOCATOR_COMPARISON_SSOT.md: Detailed SSOT methodology

- M2 milestone status: 44.46% (target 55%, gap -10.54pp) - structural improvements needed

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Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>
 2025-12-18 18:50:00 +09:00
Moe Charm (CI)
043d34ad5a Phase 75-2: C5-only Inline Slots (P2) - GO (+1.10%) 
Extends Phase 75-1 pattern to C5 class (28.5% of C4-C7 ops):
- Created 4 new boxes: env_box, tls_box, fast_path_api, TLS variable
- Integration: 2 minimal boundary points (alloc/free for C5)
- Test strategy: C5-only isolation (baseline C5=OFF+C6=ON, treatment C5=ON+C6=ON)
- Default OFF: zero overhead when disabled

Results (10-run Mixed SSOT, WS=400, C6 already enabled):
- Baseline (C5=OFF, C6=ON): 44.26 M ops/s (σ=0.37)
- Treatment (C5=ON, C6=ON): 44.74 M ops/s (σ=0.54)
- Delta: +0.49 M ops/s (+1.10%)

Status: ✅ GO - C5 individual contribution confirmed
Cumulative since Phase 75-0: +2.87% (C6) + 1.10% (C5) = potential +3.97% combined
Next: Phase 75-3 (test C5+C6 interaction + non-additivity + promote to preset default)

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Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>
 2025-12-18 08:39:48 +09:00
Moe Charm (CI)
0009ce13b3 Phase 75-1: C6-only Inline Slots (P2) - GO (+2.87%) 
Modular implementation of hot-class inline slots optimization:
- Created 5 new boxes: env_box, tls_box, fast_path_api, integration_box, test_script
- Single decision point at TLS init (ENV gate: HAKMEM_TINY_C6_INLINE_SLOTS=0/1)
- Integration: 2 minimal boundary points (alloc/free paths for C6 class)
- Default OFF: zero overhead when disabled (full backward compatibility)

Results (10-run Mixed SSOT, WS=400):
- Baseline (C6 inline OFF):  44.24 M ops/s
- Treatment (C6 inline ON):  45.51 M ops/s
- Delta: +1.27 M ops/s (+2.87%)

Status: ✅ GO - Strong improvement via C6 ring buffer fast-path
Mechanism: Branch elimination on unified_cache_push/pop for C6 allocations
Next: Phase 75-2 (add C5 inline slots, target 85% C4-C7 coverage)

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Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>
 2025-12-18 08:22:09 +09:00
Moe Charm (CI)
a6ab262ad2 Phase 70-0: Infrastructure prep for refill tuning (Observability + WarmPool Sizing) 
- Observability Fix: Enabled unified cache hit/miss stats in release builds when HAKMEM_UNIFIED_CACHE_STATS_COMPILED is set.
- WarmPool Sizing: Decoupled hardcoded '12' from prefill logic; now uses TINY_WARM_POOL_DEFAULT_PER_CLASS macro and respects ENV overrides.
- Increased TINY_WARM_POOL_MAX_PER_CLASS to 32 to support wider ENV sweeps.
- Added unified_cache_auto_stats destructor to dump metrics at exit (replacing debug print hack).
 2025-12-18 03:02:40 +09:00
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)

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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)
87fa27518c Phase 15 v1: UnifiedCache FIFO→LIFO NEUTRAL (-0.70% Mixed, +0.42% C7) 
Transform existing array-based UnifiedCache from FIFO ring to LIFO stack.

A/B Results:
- Mixed (16-1024B): -0.70% (52,965,966 → 52,593,948 ops/s)
- C7-only (1025-2048B): +0.42% (78,010,783 → 78,335,509 ops/s)

Verdict: NEUTRAL (both below +1.0% GO threshold) - freeze as research box

Implementation:
- L0 ENV gate: tiny_unified_lifo_env_box.{h,c} (HAKMEM_TINY_UNIFIED_LIFO=0/1)
- L1 LIFO ops: tiny_unified_lifo_box.h (unified_cache_try_pop/push_lifo)
- L2 integration: tiny_front_hot_box.h (mode check at entry)
- Reuses existing slots[] array (no intrusive pointers)

Root Causes:
1. Mode check overhead (tiny_unified_lifo_enabled() call)
2. Minimal LIFO vs FIFO locality delta in practice
3. Existing FIFO ring already well-optimized

Bonus Fix: LTO bug for tiny_c7_preserve_header_enabled() (Phase 13/14 latent issue)
- Converted static inline to extern + non-inline implementation
- Fixes undefined reference during LTO linking

Design: docs/analysis/PHASE15_UNIFIEDCACHE_LIFO_1_DESIGN.md
Results: docs/analysis/PHASE15_UNIFIEDCACHE_LIFO_1_AB_TEST_RESULTS.md

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Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>
 2025-12-15 02:19:26 +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)

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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%)

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Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>
 2025-12-13 18:46:11 +09:00
Moe Charm (CI)
f90e261c57 Complete Phase 1.2: Centralize layout definitions in tiny_layout_box.h 
Changes:
- Updated ptr_conversion_box.h: Use TINY_HEADER_SIZE instead of hardcoded -1
- Updated tiny_front_hot_box.h: Use tiny_user_offset() for BASE->USER conversion
- Updated tiny_front_cold_box.h: Use tiny_user_offset() for BASE->USER conversion
- Added tiny_layout_box.h includes to both front box headers

Box theory: Layout parameters now isolated in dedicated Box component.
All offset arithmetic centralized - no scattered +1/-1 arithmetic.

Verified: Build succeeds (make clean && make shared -j8)

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Co-Authored-By: Claude <noreply@anthropic.com>
 2025-12-03 17:18:31 +09:00
Moe Charm (CI)
c2716f5c01 Implement Phase 2: Headerless Allocator Support (Partial) 
- Feature: Added HAKMEM_TINY_HEADERLESS toggle (A/B testing)
- Feature: Implemented Headerless layout logic (Offset=0)
- Refactor: Centralized layout definitions in tiny_layout_box.h
- Refactor: Abstracted pointer arithmetic in free path via ptr_conversion_box.h
- Verification: sh8bench passes in Headerless mode (No TLS_SLL_HDR_RESET)
- Known Issue: Regression in Phase 1 mode due to blind pointer conversion logic
 2025-12-03 12:11:27 +09:00
Moe Charm (CI)
04186341c1 Phase 4-Step2: Add Hot/Cold Path Box (+7.3% performance) 
Implemented Hot/Cold Path separation using Box pattern for Tiny allocations:

Performance Improvement (without PGO):
- Baseline (Phase 26-A):     53.3 M ops/s
- Hot/Cold Box (Phase 4-Step2): 57.2 M ops/s
- Gain: +7.3% (+3.9 M ops/s)

Implementation:
1. core/box/tiny_front_hot_box.h - Ultra-fast hot path (1 branch)
   - Removed range check (caller guarantees valid class_idx)
   - Inline cache hit path with branch prediction hints
   - Debug metrics with zero overhead in Release builds

2. core/box/tiny_front_cold_box.h - Slow cold path (noinline, cold)
   - Refill logic (batch allocation from SuperSlab)
   - Drain logic (batch free to SuperSlab)
   - Error reporting and diagnostics

3. core/front/malloc_tiny_fast.h - Updated to use Hot/Cold Boxes
   - Hot path: tiny_hot_alloc_fast() (1 branch: cache empty check)
   - Cold path: tiny_cold_refill_and_alloc() (noinline, cold attribute)
   - Clear separation improves i-cache locality

Branch Analysis:
- Baseline: 4-5 branches in hot path (range check + cache check + refill logic mixed)
- Hot/Cold Box: 1 branch in hot path (cache empty check only)
- Reduction: 3-4 branches eliminated from hot path

Design Principles (Box Pattern):
✅ Single Responsibility: Hot path = cache hit only, Cold path = refill/errors
✅ Clear Contract: Hot returns NULL on miss, Cold handles miss
✅ Observable: Debug metrics (TINY_HOT_METRICS_*) gated by NDEBUG
✅ Safe: Branch prediction hints (TINY_HOT_LIKELY/UNLIKELY)
✅ Testable: Isolated hot/cold paths, easy A/B testing

PGO Status:
- Temporarily disabled (build issues with __gcov_merge_time_profile)
- Will re-enable PGO in future commit after resolving gcc/lto issues
- Current benchmarks are without PGO (fair A/B comparison)

Other Changes:
- .gitignore: Added *.d files (dependency files, auto-generated)
- Makefile: PGO targets temporarily disabled (show informational message)
- build_pgo.sh: Temporarily disabled (show "PGO paused" message)

Next: Phase 4-Step3 (Front Config Box, target +5-8%)

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Co-Authored-By: Claude <noreply@anthropic.com>
 2025-11-29 11:58:37 +09:00