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6b1382959c
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Phase 7-1 PoC: Region-ID Direct Lookup (+39%~+436% improvement!)
Implemented ultra-fast header-based free path that eliminates SuperSlab
lookup bottleneck (100+ cycles → 5-10 cycles).
## Key Changes
1. **Smart Headers** (core/tiny_region_id.h):
- 1-byte header before each allocation stores class_idx
- Memory layout: [Header: 1B] [User data: N-1B]
- Overhead: <2% average (0% for Slab[0] using wasted padding)
2. **Ultra-Fast Allocation** (core/tiny_alloc_fast.inc.h):
- Write header at base: *base = class_idx
- Return user pointer: base + 1
3. **Ultra-Fast Free** (core/tiny_free_fast_v2.inc.h):
- Read class_idx from header (ptr-1): 2-3 cycles
- Push base (ptr-1) to TLS freelist: 3-5 cycles
- Total: 5-10 cycles (vs 500+ cycles current!)
4. **Free Path Integration** (core/box/hak_free_api.inc.h):
- Removed SuperSlab lookup from fast path
- Direct header validation (no lookup needed!)
5. **Size Class Adjustment** (core/hakmem_tiny.h):
- Max tiny size: 1023B (was 1024B)
- 1024B requests → Mid allocator fallback
## Performance Results
| Size | Baseline | Phase 7 | Improvement |
|------|----------|---------|-------------|
| 128B | 1.22M | 6.54M | **+436%** 🚀 |
| 512B | 1.22M | 1.70M | **+39%** |
| 1023B | 1.22M | 1.92M | **+57%** |
## Build & Test
Enable Phase 7:
make HEADER_CLASSIDX=1 bench_random_mixed_hakmem
Run benchmark:
HAKMEM_TINY_USE_SUPERSLAB=1 ./bench_random_mixed_hakmem 10000 128 1234567
## Known Issues
- 1024B requests fallback to Mid allocator (by design)
- Target 40-60M ops/s not yet reached (current: 1.7-6.5M)
- Further optimization needed (TLS capacity tuning, refill optimization)
## Credits
Design: ChatGPT Pro Ultrathink, Claude Code
Implementation: Claude Code with Task Agent Ultrathink support
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
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2025-11-08 03:18:17 +09:00 |
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b7021061b8
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Fix: CRITICAL double-allocation bug in trc_linear_carve()
Root Cause:
trc_linear_carve() used meta->used as cursor, but meta->used decrements
on free, causing already-allocated blocks to be re-carved.
Evidence:
- [LINEAR_CARVE] used=61 batch=1 → block 61 created
- (blocks freed, used decrements 62→59)
- [LINEAR_CARVE] used=59 batch=3 → blocks 59,60,61 RE-CREATED!
- Result: double-allocation → memory corruption → SEGV
Fix Implementation:
1. Added TinySlabMeta.carved (monotonic counter, never decrements)
2. Changed trc_linear_carve() to use carved instead of used
3. carved tracks carve progress, used tracks active count
Files Modified:
- core/superslab/superslab_types.h: Add carved field
- core/tiny_refill_opt.h: Use carved in trc_linear_carve()
- core/hakmem_tiny_superslab.c: Initialize carved=0
- core/tiny_alloc_fast.inc.h: Add next pointer validation
- core/hakmem_tiny_free.inc: Add drain/free validation
Test Results:
✅ bench_random_mixed: 950,037 ops/s (no crash)
✅ Fail-fast mode: 651,627 ops/s (with diagnostic logs)
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
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2025-11-08 01:18:37 +09:00 |
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a430545820
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Phase 6-2.8: SuperSlab modular refactoring (665 lines → 104 lines)
目的: hakmem_tiny_superslab.h の肥大化を解消 (500+ 行)
実装内容:
1. superslab_types.h を作成
- SuperSlab 構造体定義 (TinySlabMeta, SuperSlab)
- 設定定数 (SUPERSLAB_SIZE_MAX, TINY_NUM_CLASSES_SS)
- コンパイル時アサーション
2. superslab_inline.h を作成
- ホットパス用インライン関数を集約
- ss_slabs_capacity(), slab_index_for()
- tiny_slab_base_for(), ss_remote_push()
- _ss_remote_drain_to_freelist_unsafe()
- Fail-fast validation helpers
- ACE helpers (hak_now_ns, hak_tiny_superslab_next_lg)
3. hakmem_tiny_superslab.h をリファクタリング
- 665 行 → 104 行 (-84%)
- include のみに書き換え
- 関数宣言と extern 宣言のみ残す
効果:
✅ ビルド成功 (libhakmem.so, larson_hakmem)
✅ Mid-Large allocator テスト通過 (3.98M ops/s)
⚠️ Tiny allocator の freelist corruption バグは未解決 (リファクタリングのスコープ外)
注意:
- Phase 6-2.6/6-2.7 の freelist バグは依然として存在
- リファクタリングは保守性向上のみが目的
- バグ修正は次のフェーズで対応
🤖 Generated with Claude Code
Co-Authored-By: Claude <noreply@anthropic.com>
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2025-11-07 23:05:33 +09:00 |
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