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deecda7336
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Phase 3 C2: Slab Metadata Cache Optimization (3 patches) - NEUTRAL
Patch 1: Policy Hot Cache
- Add TinyPolicyHot struct (route_kind[8] cached in TLS)
- Eliminate policy_snapshot() calls (~2 memory ops saved)
- Safety: disabled when learner v7 active
- Files: tiny_metadata_cache_env_box.h, tiny_metadata_cache_hot_box.{h,c}
- Integration: malloc_tiny_fast.h route selection
Patch 2: First Page Inline Cache
- Cache current slab page pointer in TLS per-class
- Avoid superslab metadata lookup (1-2 memory ops)
- Fast-path in tiny_legacy_fallback_free_base()
- Files: tiny_first_page_cache.h, tiny_unified_cache.c
- Integration: tiny_legacy_fallback_box.h
Patch 3: Bounds Check Compile-out
- Hardcode unified_cache capacity as MACRO constant
- Eliminate modulo operation (constant fold)
- Macros: TINY_UNIFIED_CACHE_CAPACITY_POW2=11, CAPACITY=2048, MASK=2047
- File: tiny_unified_cache.h
A/B Test Results (Mixed, 10-run):
- Baseline (C2=0): 40.43M ops/s (avg), 40.72M ops/s (median)
- Optimized (C2=1): 40.25M ops/s (avg), 40.29M ops/s (median)
- Improvement: -0.45% (avg), -1.06% (median)
- DECISION: NEUTRAL (within ±1.0% threshold)
- Action: Keep as research box (ENV gate OFF by default)
Cumulative Gain (Phase 2-3):
- B3 (Routing shape): +2.89%
- B4 (Wrapper split): +1.47%
- C3 (Static routing): +2.20%
- C2 (Metadata cache): -0.45%
- Total: ~6.1% (from baseline 37.5M → 39.8M ops/s)
🤖 Generated with Claude Code
Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>
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2025-12-13 19:19:42 +09:00 |
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d54893ea1d
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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%)
🤖 Generated with Claude Code
Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>
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2025-12-13 18:46:11 +09:00 |
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49969d2e0f
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feat(Phase 1-1): Complete getenv elimination from malloc/free hot paths (+39-42% perf)
## Summary
Eliminated all getenv() calls from malloc/free wrappers and allocator hot paths by implementing
constructor-based environment variable caching. This achieves 39-42% performance improvement
(36s → 22s on sh8bench single-thread).
## Performance Impact
- sh8bench 1 thread: 35-36s → 21-22s (+39-42% improvement) 🚀
- sh8bench 8 threads: ~15s (maintained)
- getenv overhead: 36.32% → 0% (completely eliminated)
## Changes
### New Files
- **core/box/tiny_env_box.{c,h}**: Centralized environment variable cache for Tiny allocator
- Caches 43 environment variables (HAKMEM_TINY_*, HAKMEM_SLL_*, HAKMEM_SS_*, etc.)
- Constructor-based initialization with atomic CAS for thread safety
- Inline accessor tiny_env_cfg() for hot path access
- **core/box/wrapper_env_box.{c,h}**: Environment cache for malloc/free wrappers
- Caches 3 wrapper variables (HAKMEM_STEP_TRACE, HAKMEM_LD_SAFE, HAKMEM_FREE_WRAP_TRACE)
- Constructor priority 101 ensures early initialization
- Replaces all lazy-init patterns in wrapper code
### Modified Files
- **Makefile**: Added tiny_env_box.o and wrapper_env_box.o to OBJS_BASE and SHARED_OBJS
- **core/box/hak_wrappers.inc.h**:
- Removed static lazy-init variables (g_step_trace, ld_safe_mode cache)
- Replaced with wrapper_env_cfg() lookups (wcfg->step_trace, wcfg->ld_safe_mode)
- All getenv() calls eliminated from malloc/free hot paths
- **core/hakmem.c**:
- Added hak_ld_env_init() with constructor for LD_PRELOAD caching
- Added hak_force_libc_ctor() for HAKMEM_FORCE_LIBC_ALLOC* caching
- Simplified hak_ld_env_mode() to return cached value only
- Simplified hak_force_libc_alloc() to use cached values
- Eliminated all getenv/atoi calls from hot paths
## Technical Details
### Constructor Initialization Pattern
All environment variables are now read once at library load time using __attribute__((constructor)):
```c
__attribute__((constructor(101)))
static void wrapper_env_ctor(void) {
wrapper_env_init_once(); // Atomic CAS ensures exactly-once init
}
```
### Thread Safety
- Atomic compare-and-swap (CAS) ensures single initialization
- Spin-wait for initialization completion in multi-threaded scenarios
- Memory barriers (memory_order_acq_rel) ensure visibility
### Hot Path Impact
Before: Every malloc/free → getenv("LD_PRELOAD") + getenv("HAKMEM_STEP_TRACE") + ...
After: Every malloc/free → Single pointer dereference (wcfg->field)
## Next Optimization Target (Phase 1-2)
Perf analysis reveals libc fallback accounts for ~51% of cycles:
- _int_malloc: 15.04%
- malloc: 9.81%
- _int_free: 10.07%
- malloc_consolidate: 9.27%
- unlink_chunk: 6.82%
Reducing libc fallback from 51% → 10% could yield additional +25-30% improvement.
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
Co-Authored-By: ChatGPT <chatgpt@openai.com>
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2025-12-02 16:16:51 +09:00 |
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