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Author SHA1 Message Date
Moe Charm (CI)
b7085c47e1 Phase 35-39: FAST build optimization complete (+7.13% cumulative) 
Phase 35-A: BENCH_MINIMAL gate function elimination (GO +4.39%)
- tiny_front_v3_enabled() → constant true
- tiny_metadata_cache_enabled() → constant 0
- learner_v7_enabled() → constant false
- small_learner_v2_enabled() → constant false

Phase 36: Policy snapshot init-once (GO +0.71%)
- small_policy_v7_snapshot() version check skip in BENCH_MINIMAL
- TLS cache for policy snapshot

Phase 37: Standard TLS cache (NO-GO -0.07%)
- TLS cache for Standard build attempted
- Runtime gate overhead negates benefit

Phase 38: FAST/OBSERVE/Standard workflow established
- make perf_fast, make perf_observe targets
- Scorecard and documentation updates

Phase 39: Hot path gate constantization (GO +1.98%)
- front_gate_unified_enabled() → constant 1
- alloc_dualhot_enabled() → constant 0
- g_bench_fast_front, g_v3_enabled blocks → compile-out
- free_dispatch_stats_enabled() → constant false

Results:
- FAST v3: 56.04M ops/s (47.4% of mimalloc)
- Standard: 53.50M ops/s (45.3% of mimalloc)
- M1 target (50%): 5.5% remaining

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

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
 2025-12-16 15:01:56 +09:00
Moe Charm (CI)
ec87025da6 Phase 17 v2 (FORCE_LIBC fix) + Phase 19-1b (FastLane Direct) — GO (+5.88%) 
## Phase 17 v2: FORCE_LIBC Gap Validation Fix

**Critical bug fix**: Phase 17 v1 の測定が壊れていた

**Problem**: HAKMEM_FORCE_LIBC_ALLOC=1 が FastLane より後でしか見えず、
same-binary A/B が実質 "hakmem vs hakmem" になっていた（+0.39% 誤測定）

**Fix**: core/box/hak_wrappers.inc.h:171 と :645 に g_force_libc_alloc==1 の
early bypass を追加、__libc_malloc/__libc_free に最初に直行

**Result**: 正しい同一バイナリ A/B 測定
- hakmem (FORCE_LIBC=0): 48.99M ops/s
- libc (FORCE_LIBC=1): 79.72M ops/s (+62.7%)
- system binary: 88.06M ops/s (+10.5% vs libc)

**Gap 分解**:
- Allocator 差: +62.7% (主戦場)
- Layout penalty: +10.5% (副次的)

**Conclusion**: Case A 確定 (allocator dominant, NOT layout)
Phase 17 v1 の Case B 判定は誤り。

Files:
- docs/analysis/PHASE17_FORCE_LIBC_GAP_VALIDATION_1_AB_TEST_RESULTS.md (v2)
- docs/analysis/PHASE17_FORCE_LIBC_GAP_VALIDATION_1_NEXT_INSTRUCTIONS.md (updated)

---

## Phase 19: FastLane Instruction Reduction Analysis

**Goal**: libc との instruction gap (-35% instructions, -56% branches) を削減

**perf stat 分析** (FORCE_LIBC=0 vs 1, 200M ops):
- hakmem: 209.09 instructions/op, 52.33 branches/op
- libc: 135.92 instructions/op, 22.93 branches/op
- Delta: +73.17 instructions/op (+53.8%), +29.40 branches/op (+128.2%)

**Hot path** (perf report):
- front_fastlane_try_free: 23.97% cycles
- malloc wrapper: 23.84% cycles
- free wrapper: 6.82% cycles
- **Wrapper overhead: ~55% of all cycles**

**Reduction candidates**:
- A: Wrapper layer 削除 (-17.5 inst/op, +10-15% 期待)
- B: ENV snapshot 統合 (-10.0 inst/op, +5-8%)
- C: Stats 削除 (-5.0 inst/op, +3-5%)
- D: Header inline (-4.0 inst/op, +2-3%)
- E: Route fast path (-3.5 inst/op, +2-3%)

Files:
- docs/analysis/PHASE19_FASTLANE_INSTRUCTION_REDUCTION_1_DESIGN.md
- docs/analysis/PHASE19_FASTLANE_INSTRUCTION_REDUCTION_2_NEXT_INSTRUCTIONS.md

---

## Phase 19-1b: FastLane Direct — GO (+5.88%)

**Strategy**: Wrapper layer を bypass し、core allocator を直接呼ぶ
- free() → free_tiny_fast() (not free_tiny_fast_hot)
- malloc() → malloc_tiny_fast()

**Phase 19-1 が NO-GO (-3.81%) だった原因**:
1. __builtin_expect(fastlane_direct_enabled(), 0) が逆効果（A/B 不公平）
2. free_tiny_fast_hot() が誤選択（free_tiny_fast() が勝ち筋）

**Phase 19-1b の修正**:
1. __builtin_expect() 削除
2. free_tiny_fast() を直接呼び出し

**Result** (Mixed, 10-run, 20M iters, ws=400):
- Baseline (FASTLANE_DIRECT=0): 49.17M ops/s
- Optimized (FASTLANE_DIRECT=1): 52.06M ops/s
- **Delta: +5.88%** (GO 基準 +5% クリア)

**perf stat** (200M iters):
- Instructions/op: 199.90 → 169.45 (-30.45, -15.23%)
- Branches/op: 51.49 → 41.52 (-9.97, -19.36%)
- Cycles/op: 88.88 → 84.37 (-4.51, -5.07%)
- I-cache miss: 111K → 98K (-11.79%)

**Trade-offs** (acceptable):
- iTLB miss: +41.46% (front-end cost)
- dTLB miss: +29.15% (backend cost)
- Overall gain (+5.88%) outweighs costs

**Implementation**:
1. **ENV gate**: core/box/fastlane_direct_env_box.{h,c}
   - HAKMEM_FASTLANE_DIRECT=0/1 (default: 0, opt-in)
   - Single _Atomic global (wrapper キャッシュ問題を解決)

2. **Wrapper 修正**: core/box/hak_wrappers.inc.h
   - malloc: direct call to malloc_tiny_fast() when FASTLANE_DIRECT=1
   - free: direct call to free_tiny_fast() when FASTLANE_DIRECT=1
   - Safety: !g_initialized では direct 使わない、fallback 維持

3. **Preset 昇格**: core/bench_profile.h:88
   - bench_setenv_default("HAKMEM_FASTLANE_DIRECT", "1")
   - Comment: +5.88% proven on Mixed, 10-run

4. **cleanenv 更新**: scripts/run_mixed_10_cleanenv.sh:22
   - HAKMEM_FASTLANE_DIRECT=${HAKMEM_FASTLANE_DIRECT:-1}
   - Phase 9/10 と同様に昇格

**Verdict**: GO — 本線採用、プリセット昇格完了

**Rollback**: HAKMEM_FASTLANE_DIRECT=0 で既存 FastLane path に戻る

Files:
- core/box/fastlane_direct_env_box.{h,c} (new)
- core/box/hak_wrappers.inc.h (modified)
- core/bench_profile.h (preset promotion)
- scripts/run_mixed_10_cleanenv.sh (ENV default aligned)
- Makefile (new obj)
- docs/analysis/PHASE19_1B_FASTLANE_DIRECT_REVISED_AB_TEST_RESULTS.md

---

## Cumulative Performance

- Baseline (all optimizations OFF): ~40M ops/s (estimated)
- Current (Phase 19-1b): 52.06M ops/s
- **Cumulative gain: ~+30% from baseline**

Remaining gap to libc (79.72M):
- Current: 52.06M ops/s
- Target: 79.72M ops/s
- **Gap: +53.2%** (was +62.7% before Phase 19-1b)

Next: Phase 19-2 (ENV snapshot consolidation, +5-8% expected)

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

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>
 2025-12-15 11:28:40 +09:00
Moe Charm (CI)
f8e7cf05b4 Phase 16 v1 NEUTRAL, Phase 17 Case B confirmed, Phase 18 design added 
## Phase 16 v1: Front FastLane Alloc LEGACY Direct — NEUTRAL (+0.62%)

Target: Reduce alloc-side fixed costs by adding LEGACY direct path to
FastLane entry, mirroring Phase 9/10 free-side winning pattern.

Result: +0.62% on Mixed (below +1.0% GO threshold) → NEUTRAL, freeze as
research box (default OFF).

Critical issue: Initial impl crashed (segfault) for C4-C7. Root cause:
unified_cache_refill() incompatibility. Safety fix: Limited to C0-C3
only (matching existing dualhot pattern).

Files:
- core/box/front_fastlane_alloc_legacy_direct_env_box.{h,c} (new)
- core/box/front_fastlane_box.h (LEGACY direct path, lines 93-119)
- core/bench_profile.h (env refresh sync)
- Makefile (new obj)
- docs/analysis/PHASE16_*.md (design/results/instructions)

ENV: HAKMEM_FRONT_FASTLANE_ALLOC_LEGACY_DIRECT=0 (default OFF, opt-in)

Verdict: Research box frozen. Phase 14-16 plateau confirms dispatch/
routing optimization ROI is exhausted post-Phase-6 FastLane collapse.

---

## Phase 17: FORCE_LIBC Gap Validation — Case B Confirmed

Purpose: Validate "system malloc faster" observation using same-binary
A/B testing to isolate allocator logic差 vs binary layout penalty.

Method:
- Same-binary toggle: HAKMEM_FORCE_LIBC_ALLOC=0/1 (bench_random_mixed_hakmem)
- System binary: bench_random_mixed_system (21K separate binary)
- Perf stat: Hardware counter analysis (I-cache, cycles, instructions)

Result: **Case B confirmed** — Allocator差 negligible, layout penalty dominates.

Gap breakdown (Mixed, 20M iters, ws=400):
- hakmem (FORCE_LIBC=0): 48.12M ops/s
- libc (FORCE_LIBC=1, same binary): 48.31M ops/s → +0.39% (noise level)
- system binary (21K): 83.85M ops/s → +73.57% vs libc, +74.26% vs hakmem

Perf stat (200M iters):
- I-cache misses: 153K (hakmem) → 68K (system) = -55% (smoking gun)
- Cycles: 17.9B → 10.2B = -43%
- Instructions: 41.3B → 21.5B = -48%
- Binary size: 653K → 21K (30x difference)

Root cause: Binary size (30x) causes I-cache thrashing. Code bloat >>
algorithmic efficiency.

Conclusion: Phase 12's "system malloc 1.6x faster" was real, but
misattributed. Gap is layout/I-cache, NOT allocator algorithm.

Files:
- docs/analysis/PHASE17_*.md (results/instructions)
- scripts/run_mixed_10_cleanenv.sh (Phase 9/10 defaults aligned)

Next: Phase 18 Hot Text Isolation (layout optimization, not algorithm opt)

---

## Phase 18: Hot Text Isolation — Design Added

Purpose: Reduce I-cache misses + instruction footprint via layout control
(binary optimization, not allocator algorithm changes).

Strategy (v1 → v2 progression):

v1 (TU split + hot/cold attrs + optional gc-sections):
- Target: +2% throughput (GO threshold, realistic for layout tweaks)
- Secondary: I-cache -10%, instructions -5% (direction confirmation)
- Risk: Low (reversible via build knob)
- Expected: +0-2% (NEUTRAL likely, but validates approach)

v2 (BENCH_MINIMAL compile-out):
- Target: +10-20% throughput (本命)
- Method: Conditional compilation removes stats/ENV/debug from hot path
- Expected: Instruction count -30-40% → significant I-cache improvement

Files:
- docs/analysis/PHASE18_*.md (design/instructions)
- CURRENT_TASK.md (Phase 17 complete, Phase 18 v1/v2 plan)

Build gate: HOT_TEXT_ISOLATION=0/1 (Makefile knob)

Next: Implement Phase 18 v1 (TU split first, BENCH_MINIMAL if v1 NEUTRAL)

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

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>
 2025-12-15 05:25:47 +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)
71b1354d32 Phase 10: FREE-TINY-FAST MONO LEGACY DIRECT (GO +1.89%) 
Results:
- A/B test: +1.89% on Mixed (10-run, clean env)
- Baseline: 51.96M ops/s
- Optimized: 52.94M ops/s
- Improvement: +984K ops/s (+1.89%)
- C6-heavy verification: +7.86% (nonlegacy_mask works correctly, no misfires)

Strategy:
- Extend Phase 9 (C0-C3 DUALHOT) to C4-C7 LEGACY DIRECT
- Fail-Fast principle: Never misclassify MID/ULTRA/V7 as LEGACY
- nonlegacy_mask: Cached at init, hot path uses single bit operation

Success factors:
1. Performance improvement: +1.89% (1.9x GO threshold)
2. Safety verified: nonlegacy_mask prevents MID v3 misfire in C6-heavy
3. Phase 9 coexistence: C0-C3 (Phase 9) + C4-C7 (Phase 10) = full LEGACY coverage
4. Minimal overhead: Single bit operation in hot path (mask & (1u<<class))

Implementation:
- Patch 1: ENV gate box (free_tiny_fast_mono_legacy_direct_env_box.h)
  - ENV: HAKMEM_FREE_TINY_FAST_MONO_LEGACY_DIRECT=0/1 (default 0)
  - nonlegacy_mask cached (reuses free_policy_fast_v2_nonlegacy_mask())
  - Probe window: 64 (avoid bench_profile putenv race)
- Patch 2: Early-exit in free_tiny_fast() (malloc_tiny_fast.h)
  - Conditions: !nonlegacy_mask, route==LEGACY, !LARSON_FIX, done==1
  - Direct call: tiny_legacy_fallback_free_base()
- Patch 3: Visibility (free_path_stats_box.h)
  - mono_legacy_direct_hit counter (compile-out in release)
- Patch 4: cleanenv extension (run_mixed_10_cleanenv.sh)
  - ENV leak protection

Safety verification (C6-heavy):
- OFF: 19.75M ops/s
- ON: 21.30M ops/s (+7.86%)
- nonlegacy_mask correctly excludes C6 (MID v3 active)
- Improvement from C0-C5, C7 direct path acceleration

Files modified:
- core/bench_profile.h: add to MIXED_TINYV3_C7_SAFE preset
- core/front/malloc_tiny_fast.h: early-exit insertion
- core/box/free_path_stats_box.h: counter
- core/box/free_tiny_fast_mono_legacy_direct_env_box.h: NEW (ENV gate + nonlegacy_mask)
- scripts/run_mixed_10_cleanenv.sh: ENV leak protection

Health check: PASSED (all profiles)

Promotion: Added to MIXED_TINYV3_C7_SAFE preset (default ON, opt-out)

Rollback: HAKMEM_FREE_TINY_FAST_MONO_LEGACY_DIRECT=0

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

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>
 2025-12-14 20:09:40 +09:00
Moe Charm (CI)
871034da1f Phase 9: FREE-TINY-FAST MONO DUALHOT (GO +2.72%) 
Results:
- A/B test: +2.72% on Mixed (10-run, clean env)
- Baseline: 48.89M ops/s
- Optimized: 50.22M ops/s
- Improvement: +1.33M ops/s (+2.72%)
- Stability: Standard deviation reduced by 60.8% (2.44M → 955K ops/s)

Strategy:
- Transplant C0-C3 "second hot" path to monolithic free_tiny_fast()
- Early-exit within monolithic (no hot/cold split)
- FastLane free now benefits from C0-C3 direct path

Success factors:
1. Performance improvement: +2.72% (2.7x GO threshold)
2. Stability improvement: 2.6x more stable (stdev 60.8% reduction)
3. Learned from Phase 7 failure:
   - Phase 7: Function split (hot/cold) → NO-GO
   - Phase 9: Early-exit within monolithic → GO
4. FastLane free compatibility: C0-C3 direct path now works with FastLane
5. Policy snapshot overhead reduction: C0-C3 (48% of Mixed) skip route lookup

Implementation:
- Patch 1: ENV gate box (free_tiny_fast_mono_dualhot_env_box.h)
  - ENV: HAKMEM_FREE_TINY_FAST_MONO_DUALHOT=0/1 (default 0)
  - Probe window: 64 (avoid bench_profile putenv race)
- Patch 2: Early-exit in free_tiny_fast() (malloc_tiny_fast.h)
  - Conditions: class_idx <= 3, !LARSON_FIX, route==LEGACY
  - Direct call: tiny_legacy_fallback_free_base()
- Patch 3: Visibility (free_path_stats_box.h)
  - mono_dualhot_hit counter (compile-out in release)
- Patch 4: cleanenv extension (run_mixed_10_cleanenv.sh)
  - ENV leak protection

Files modified:
- core/bench_profile.h: add to MIXED_TINYV3_C7_SAFE preset
- core/front/malloc_tiny_fast.h: early-exit insertion
- core/box/free_path_stats_box.h: counter
- core/box/free_tiny_fast_mono_dualhot_env_box.h: NEW (ENV gate)
- scripts/run_mixed_10_cleanenv.sh: ENV leak protection

Health check: PASSED (all profiles)

Promotion: Added to MIXED_TINYV3_C7_SAFE preset (default ON, opt-out)

Rollback: HAKMEM_FREE_TINY_FAST_MONO_DUALHOT=0

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

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>
 2025-12-14 19:16:49 +09:00
Moe Charm (CI)
6d38511318 Phase 5: E7 prune no-go (keep frozen boxes); add clean-env runner 2025-12-14 08:11:20 +09:00