d54893ea1d
Phase 3 C3: Static Routing A/B Test ADOPT (+2.20% Mixed gain)
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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
04186341c1
Phase 4-Step2: Add Hot/Cold Path Box (+7.3% performance)
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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%)
🤖 Generated with [Claude Code](https://claude.com/claude-code )
Co-Authored-By: Claude <noreply@anthropic.com >
2025-11-29 11:58:37 +09:00
