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ccccabd944
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Phase 17-1: Small-Mid Allocator - TLS Frontend Cache (結果: ±0.3%, 層分離成功)
Summary:
========
Phase 17-1 implements Small-Mid allocator as TLS frontend cache with Tiny backend delegation.
Result: Clean layer separation achieved with minimal overhead (±0.3%), but no performance gain.
Conclusion: Frontend-only approach is dead end. Phase 17-2 (dedicated backend) required for 2-3x target.
Implementation:
===============
1. Small-Mid TLS frontend (256B/512B/1KB - 3 classes)
- TLS freelist (32/24/16 capacity)
- Backend delegation to Tiny C5/C6/C7
- Header conversion (0xa0 → 0xb0)
2. Auto-adjust Tiny boundary
- When Small-Mid ON: Tiny auto-limits to C0-C5 (0-255B)
- When Small-Mid OFF: Tiny default C0-C7 (0-1023B)
- Prevents routing conflict
3. Routing order fix
- Small-Mid BEFORE Tiny (critical for proper execution)
- Fall-through on TLS miss
Files Modified:
===============
- core/hakmem_smallmid.h/c: TLS freelist + backend delegation
- core/hakmem_tiny.c: tiny_get_max_size() auto-adjust
- core/box/hak_alloc_api.inc.h: Routing order (Small-Mid → Tiny)
- CURRENT_TASK.md: Phase 17-1 results + Phase 17-2 plan
A/B Benchmark Results:
======================
| Size | Config A (OFF) | Config B (ON) | Delta | % Change |
|--------|----------------|---------------|----------|----------|
| 256B | 5.87M ops/s | 6.06M ops/s | +191K | +3.3% |
| 512B | 6.02M ops/s | 5.91M ops/s | -112K | -1.9% |
| 1024B | 5.58M ops/s | 5.54M ops/s | -35K | -0.6% |
| Overall| 5.82M ops/s | 5.84M ops/s | +20K | +0.3% |
Analysis:
=========
✅ SUCCESS: Clean layer separation (Small-Mid ↔ Tiny coexist)
✅ SUCCESS: Minimal overhead (±0.3% = measurement noise)
❌ FAIL: No performance gain (target was 2-4x)
Root Cause:
-----------
- Delegation overhead = TLS savings (net gain ≈ 0 instructions)
- Small-Mid TLS alloc: ~3-5 instructions
- Tiny backend delegation: ~3-5 instructions
- Header conversion: ~2 instructions
- No batching: 1:1 delegation to Tiny (no refill amortization)
Lessons Learned:
================
- Frontend-only approach ineffective (backend calls not reduced)
- Dedicated backend essential for meaningful improvement
- Clean separation achieved = solid foundation for Phase 17-2
Next Steps (Phase 17-2):
========================
- Dedicated Small-Mid SuperSlab backend (separate from Tiny)
- TLS batch refill (8-16 blocks per refill)
- Optimized 0xb0 header fast path (no delegation)
- Target: 12-15M ops/s (2.0-2.6x improvement)
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
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2025-11-16 02:37:24 +09:00 |
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cdaf117581
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Phase 17-1 Revision: Small-Mid Front Box Only (ChatGPT Strategy)
STRATEGY CHANGE (ChatGPT reviewed):
- Phase 17-1: Build FRONT BOX ONLY (no dedicated SuperSlab backend)
- Backend: Reuse existing Tiny SuperSlab/SharedPool APIs
- Goal: Measure performance impact before building dedicated infrastructure
- A/B test: Does thin front layer improve 256-1KB performance?
RATIONALE (ChatGPT analysis):
1. Tiny/Middle/Large need different properties - same SuperSlab causes conflict
2. Metadata shapes collide - struct bloat → L1 miss increase
3. Learning signals get muddied - size-specific control becomes difficult
IMPLEMENTATION:
- Reduced size classes: 5 → 3 (256B/512B/1KB only)
- Removed dedicated SuperSlab backend stub
- Backend: Direct delegation to hak_tiny_alloc/free
- TLS freelist: Thin front cache (32/24/16 capacity)
- Fast path: TLS hit (pop/push with header 0xb0)
- Slow path: Backend alloc via Tiny (no TLS refill)
- Free path: TLS push if space, else delegate to Tiny
ARCHITECTURE:
Tiny: 0-255B (C0-C5, unchanged)
Small-Mid: 256-1KB (SM0-SM2, Front Box, backend=Tiny)
Mid: 8KB-32KB (existing)
FILES CHANGED:
- hakmem_smallmid.h: Reduced to 3 classes, updated docs
- hakmem_smallmid.c: Removed SuperSlab stub, added backend delegation
NEXT STEPS:
- Integrate into hak_alloc_api.inc.h routing
- A/B benchmark: Small-Mid ON/OFF comparison
- If successful (2x improvement), consider Phase 17-2 dedicated backend
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
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2025-11-16 01:51:43 +09:00 |
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993c5419b7
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Phase 17-1: Small-Mid Allocator Box - Header and Stub Implementation
Created:
- core/hakmem_smallmid.h - API and size class definitions
- core/hakmem_smallmid.c - TLS freelist + ENV control (SuperSlab stub)
Design:
- 5 size classes: 256B/512B/1KB/2KB/4KB (SM0-SM4)
- TLS freelist structure (same as Tiny, completely separated)
- Header-based fast free (Phase 7 technology, magic 0xb0)
- ENV control: HAKMEM_SMALLMID_ENABLE=1 for A/B testing
- Dedicated SuperSlab pool (stub, Phase 17-2)
Boundaries:
Tiny: 0-255B (C0-C5, unchanged)
Small-Mid: 256B-4KB (SM0-SM4, NEW!)
Mid: 8KB-32KB (existing)
Implementation Status:
✅ TLS freelist operations (pop/push)
✅ ENV control (smallmid_is_enabled)
✅ Fast alloc (TLS hit path)
✅ Header-based free (0xb0 magic)
🚧 SuperSlab backend (stub, TODO Phase 17-2)
Goal: Bridge Tiny/Mid gap, improve 256B-1KB from 5.5M to 10-20M ops/s
Next: Phase 17-2 - Dedicated SuperSlab backend implementation
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
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2025-11-16 01:43:29 +09:00 |
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