Commit Graph

8 Commits

Author SHA1 Message Date
6d38511318 Phase 5: E7 prune no-go (keep frozen boxes); add clean-env runner 2025-12-14 08:11:20 +09:00
f92be5f541 Phase 5: freeze E6 env snapshot shape (no-go) 2025-12-14 07:18:59 +09:00
4124c86d99 Phase 5: freeze E5-4 malloc tiny direct (neutral) 2025-12-14 06:59:35 +09:00
580e7f4fa3 Phase 5 E5-3: Candidate Analysis (All DEFERRED) + E5-4 Instructions
E5-3 Analysis Results:
- free_tiny_fast_cold (7.14%): DEFER - cold path, low ROI
- unified_cache_push (3.39%): DEFER - already optimized
- hakmem_env_snapshot_enabled (2.97%): DEFER - low headroom

Key Insight: perf self% is time-weighted, not frequency-weighted.
Cold paths appear hot but have low total impact.

Next: E5-4 (Malloc Tiny Direct Path)
- Apply E5-1 winning pattern to malloc side
- Target: tiny_alloc_gate_fast() gate tax elimination
- ENV gate: HAKMEM_MALLOC_TINY_DIRECT=0/1

Files added:
- docs/analysis/PHASE5_E5_3_ANALYSIS_AND_RECOMMENDATIONS.md
- docs/analysis/PHASE5_E5_4_MALLOC_TINY_DIRECT_NEXT_INSTRUCTIONS.md
- core/box/free_cold_shape_env_box.{h,c} (research box, not tested)
- core/box/free_cold_shape_stats_box.{h,c} (research box, not tested)

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Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
2025-12-14 06:44:04 +09:00
75e20b29cc Phase 5 E5-1: Promote to preset + next target instructions
E5-1 Promotion:
- Added HAKMEM_FREE_TINY_DIRECT=1 to MIXED_TINYV3_C7_SAFE preset
- Updated ENV_PROFILE_PRESETS.md with rollback instructions
- Rollback: HAKMEM_FREE_TINY_DIRECT=0

A/B Test Clarification:
- Documented bench_setenv_default vs export ENV=0 interaction
- bench_setenv_default only sets if ENV is unset
- To force OFF in A/B: use value that differs from default

Next Target Selection (E5-2 vs E5-3):
- E5-2: Header write reduction (tiny_region_id_write_header)
- E5-3: ENV snapshot gate shape optimization
- Decision requires fresh perf profile on new baseline

Deliverables:
- docs/analysis/PHASE5_E5_1_FREE_TINY_DIRECT_NEXT_INSTRUCTIONS.md
- docs/analysis/PHASE5_E5_NEXT_INSTRUCTIONS.md (updated)
- docs/analysis/ENV_PROFILE_PRESETS.md (E5-1 added)
- docs/analysis/PHASE5_E5_1_FREE_TINY_DIRECT_1_AB_TEST_RESULTS.md (clarified)
- CURRENT_TASK.md (progress links)
- docs/analysis/PHASE5_POST_E1_NEXT_INSTRUCTIONS.md (progress links)

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Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>
2025-12-14 05:59:43 +09:00
6cdbd815ab Phase 5 E4 Combined: E4-1 + E4-2 (+6.43% GO, baseline consolidated)
Combined A/B Test Results (10-run Mixed):
- Baseline (both OFF): 44.48M ops/s (mean), 44.39M ops/s (median)
- Optimized (both ON): 47.34M ops/s (mean), 47.38M ops/s (median)
- Improvement: +6.43% mean, +6.74% median

Interaction Analysis:
- E4-1 alone: +3.51% (measured in separate session)
- E4-2 alone: +21.83% (measured in separate session)
- Combined: +6.43% (measured in same binary)
- Pattern: SUBADDITIVE (overlapping bottlenecks)

Key Finding: Single-binary incremental gain is the accurate metric
- E4-1 and E4-2 target overlapping TLS/branch resources
- Individual measurements were from different baselines/sessions
- Combined measurement (same binary, both flags) shows true progress

Phase 5 Total Progress:
- Original baseline (session start): 35.74M ops/s
- Combined optimized: 47.34M ops/s
- Total gain: +32.4% (cross-session, reference only)
- Same-binary gain: +6.43% (E4-1+E4-2 both ON vs both OFF)

New Baseline Perf Profile (47.0M ops/s):
- free: 37.56% self% (still top hotspot)
- tiny_alloc_gate_fast: 13.73% (reduced from 19.50%)
- malloc: 12.95% (reduced from 16.13%)
- tiny_region_id_write_header: 6.97% (header write tax)
- hakmem_env_snapshot_enabled: 4.29% (ENV overhead visible)

Health Check: PASS
- MIXED_TINYV3_C7_SAFE: 42.3M ops/s
- C6_HEAVY_LEGACY_POOLV1: 20.9M ops/s

Phase 5 E5 Candidates (from perf profile):
- E5-1: free() path internals (37.56% self%)
- E5-2: Header write reduction (6.97% self%)
- E5-3: ENV snapshot overhead (4.29% self%)

Deliverables:
- docs/analysis/PHASE5_E4_COMBINED_AB_TEST_RESULTS.md
- docs/analysis/PHASE5_E5_NEXT_INSTRUCTIONS.md
- CURRENT_TASK.md (E4 combined complete, E5 candidates)
- docs/analysis/PHASE5_POST_E1_NEXT_INSTRUCTIONS.md (E5 pointer)
- perf.data.e4combined (perf profile data)

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Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>
2025-12-14 05:36:57 +09:00
5528612f2a Phase 5 E4-2: Malloc Wrapper ENV Snapshot (+21.83% GO, ADOPTED)
Target: Consolidate malloc wrapper TLS reads + eliminate function calls
- malloc (16.13%) + tiny_alloc_gate_fast (19.50%) = 35.63% combined
- Strategy: E4-1 success pattern + function call elimination

Implementation:
- ENV gate: HAKMEM_MALLOC_WRAPPER_ENV_SNAPSHOT=0/1 (default 0)
- core/box/malloc_wrapper_env_snapshot_box.{h,c}: New box
  - Consolidates multiple TLS reads → 1 TLS read
  - Pre-caches tiny_max_size() == 256 (eliminates function call)
  - Lazy init with probe window (bench_profile putenv sync)
- core/box/hak_wrappers.inc.h: Integration in malloc() wrapper
- Makefile: Add malloc_wrapper_env_snapshot_box.o to all targets

A/B Test Results (Mixed, 10-run, 20M iters):
- Baseline (SNAPSHOT=0): 35.74M ops/s (mean), 35.75M ops/s (median)
- Optimized (SNAPSHOT=1): 43.54M ops/s (mean), 43.92M ops/s (median)
- Improvement: +21.83% mean, +22.86% median (+7.80M ops/s)

Decision: GO (+21.83% >> +1.0% threshold, 21.8x over)
- Why 6.2x better than E4-1 (+3.51%)?
  - Higher malloc call frequency (allocation-heavy workload)
  - Function call elimination (tiny_max_size pre-cached)
  - Larger target: 35.63% vs free's 25.26%
- Health check: PASS (all profiles)
- Action: PROMOTED to MIXED_TINYV3_C7_SAFE preset

Phase 5 Cumulative (estimated):
- E1 (ENV Snapshot): +3.92%
- E4-1 (Free Wrapper Snapshot): +3.51%
- E4-2 (Malloc Wrapper Snapshot): +21.83%
- Estimated combined: ~+30% (needs validation)

Next Steps:
- Combined A/B test (E4-1 + E4-2 simultaneously)
- Measure actual cumulative effect
- Profile new baseline for next optimization targets

Deliverables:
- docs/analysis/PHASE5_E4_2_MALLOC_WRAPPER_ENV_SNAPSHOT_1_DESIGN.md
- docs/analysis/PHASE5_E4_2_MALLOC_WRAPPER_ENV_SNAPSHOT_1_AB_TEST_RESULTS.md
- docs/analysis/PHASE5_E4_2_MALLOC_WRAPPER_ENV_SNAPSHOT_NEXT_INSTRUCTIONS.md
- docs/analysis/PHASE5_E4_COMBINED_AB_TEST_NEXT_INSTRUCTIONS.md (next)
- docs/analysis/ENV_PROFILE_PRESETS.md (E4-2 added)
- CURRENT_TASK.md (E4-2 complete)
- core/bench_profile.h (E4-2 promoted to default)

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Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>
2025-12-14 05:13:29 +09:00
4a070d8a14 Phase 5 E4-1: Free Wrapper ENV Snapshot (+3.51% GO, ADOPTED)
Target: Consolidate free wrapper TLS reads (2→1)
- free() is 25.26% self% (top hot spot)
- Strategy: Apply E1 success pattern (ENV snapshot) to free path

Implementation:
- ENV gate: HAKMEM_FREE_WRAPPER_ENV_SNAPSHOT=0/1 (default 0)
- core/box/free_wrapper_env_snapshot_box.{h,c}: New box
  - Consolidates 2 TLS reads → 1 TLS read (50% reduction)
  - Reduces 4 branches → 3 branches (25% reduction)
  - Lazy init with probe window (bench_profile putenv sync)
- core/box/hak_wrappers.inc.h: Integration in free() wrapper
- Makefile: Add free_wrapper_env_snapshot_box.o to all targets

A/B Test Results (Mixed, 10-run, 20M iters):
- Baseline (SNAPSHOT=0): 45.35M ops/s (mean), 45.31M ops/s (median)
- Optimized (SNAPSHOT=1): 46.94M ops/s (mean), 47.15M ops/s (median)
- Improvement: +3.51% mean, +4.07% median

Decision: GO (+3.51% >= +1.0% threshold)
- Exceeded conservative estimate (+1.5% → +3.51%)
- Similar efficiency to E1 (+3.92%)
- Health check: PASS (all profiles)
- Action: PROMOTED to MIXED_TINYV3_C7_SAFE preset

Phase 5 Cumulative:
- E1 (ENV Snapshot): +3.92%
- E4-1 (Free Wrapper Snapshot): +3.51%
- Total Phase 4-5: ~+7.5%

E3-4 Correction:
- Phase 4 E3-4 (ENV Constructor Init): NO-GO / FROZEN
- Initial A/B showed +4.75%, but investigation revealed:
  - Branch prediction hint mismatch (UNLIKELY with always-true)
  - Retest confirmed -1.78% regression
  - Root cause: __builtin_expect(..., 0) with ctor_mode==1
- Decision: Freeze as research box (default OFF)
- Learning: Branch hints need careful tuning, TLS consolidation safer

Deliverables:
- docs/analysis/PHASE5_E4_FREE_GATE_OPTIMIZATION_1_DESIGN.md
- docs/analysis/PHASE5_E4_1_FREE_WRAPPER_ENV_SNAPSHOT_NEXT_INSTRUCTIONS.md
- docs/analysis/PHASE5_E4_2_MALLOC_WRAPPER_ENV_SNAPSHOT_NEXT_INSTRUCTIONS.md (next)
- docs/analysis/PHASE5_POST_E1_NEXT_INSTRUCTIONS.md
- docs/analysis/ENV_PROFILE_PRESETS.md (E4-1 added, E3-4 corrected)
- CURRENT_TASK.md (E4-1 complete, E3-4 frozen)
- core/bench_profile.h (E4-1 promoted to default)

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Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>
2025-12-14 04:24:34 +09:00