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9ed8b9c79a
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Phase 27-28: Unified Cache stats validation + BG Spill audit
Phase 27: Unified Cache Stats A/B Test - GO (+0.74%)
- Target: g_unified_cache_* atomics (6 total) in WARM refill path
- Already implemented in Phase 23 (HAKMEM_TINY_UNIFIED_CACHE_MEASURE_COMPILED)
- A/B validation: Baseline 52.94M vs Compiled-in 52.55M ops/s
- Result: +0.74% mean, +1.01% median (both exceed +0.5% GO threshold)
- Impact: WARM path atomics have similar impact to HOT path
- Insight: Refill frequency is substantial, ENV check overhead matters
Phase 28: BG Spill Queue Atomic Audit - NO-OP
- Target: g_bg_spill_* atomics (8 total) in background spill subsystem
- Classification: 8/8 CORRECTNESS (100% untouchable)
- Key finding: g_bg_spill_len is flow control, NOT telemetry
- Used in queue depth limiting: if (qlen < target) {...}
- Operational counter (affects behavior), not observational
- Lesson: Counter name ≠ purpose, must trace all usages
- Result: NO-OP (no code changes, audit documentation only)
Cumulative Progress (Phase 24-28):
- Phase 24 (class stats): +0.93% GO
- Phase 25 (free stats): +1.07% GO
- Phase 26 (diagnostics): -0.33% NEUTRAL
- Phase 27 (unified cache): +0.74% GO
- Phase 28 (bg spill): NO-OP (audit only)
- Total: 17 atomics removed, +2.74% improvement
Documentation:
- PHASE27_UNIFIED_CACHE_STATS_RESULTS.md: Complete A/B test report
- PHASE28_BG_SPILL_ATOMIC_AUDIT.md: Detailed CORRECTNESS classification
- PHASE28_BG_SPILL_ATOMIC_PRUNE_RESULTS.md: NO-OP verdict and lessons
- ATOMIC_PRUNE_CUMULATIVE_SUMMARY.md: Updated with Phase 27-28
- CURRENT_TASK.md: Phase 29 candidate identified (Pool Hotbox v2)
Generated with Claude Code
https://claude.com/claude-code
Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>
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2025-12-16 06:12:17 +09:00 |
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8052e8b320
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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
https://claude.com/claude-code
Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>
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2025-12-16 05:35:11 +09:00 |
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