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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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