47 lines
1.5 KiB
Markdown
47 lines
1.5 KiB
Markdown
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# mimalloc Gap Summary (Phase v11b-1)
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## Current Status: 2025-12-12
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### Throughput Comparison (Mixed 16-1024B, ws=400, 10M iter)
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| Allocator | Throughput | vs mimalloc |
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|-----------|------------|-------------|
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| mimalloc | 65.5M ops/s | 1.00x |
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| hakmem v11b-1 | 50.7M ops/s | **0.77x** |
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### Progress Summary
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| Phase | Throughput | vs mimalloc | Key Change |
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|-------|------------|-------------|------------|
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| v11a-4 | 38.6M | 0.59x | baseline |
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| v11a-5 | 45.4M | 0.69x | alloc path: single switch + C7 early-exit |
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| v11b-1 | 50.7M | **0.77x** | free path: single switch + C7 early-exit |
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### perf stat Comparison (Mixed 16-1024B, v11a-5 data)
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| Metric | mimalloc | hakmem | Ratio |
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|--------|----------|--------|-------|
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| cycles | ~500M | 1.04B | 2.1x |
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| instructions | ~920M | 2.2B | 2.4x |
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| cache-misses | ~90K | 408K | 4.5x |
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| branch-misses | ~6.3M | 14.5M | 2.3x |
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### Next Target
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**フロント alloc/free 両方を最適化完了。次は backend core または cache locality 改善。**
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Candidates:
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1. **cache locality**: cache-misses 4.5x が最大差 → TLS page prefetch, hot page reuse
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2. **instructions削減**: 2.4x → inline 化, マクロ展開
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3. small-object v7 の small帯 (C2-C3) 設計
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### Key Insight
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- alloc + free 両パスで switch (jump table) 化が有効
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- フロント層の最適化だけで v11a-4 → v11b-1 で +31% 改善 (38.6M → 50.7M)
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- mimalloc との差は主に cache-misses (4.5x) と instructions (2.4x)
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---
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**Date**: 2025-12-12
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**Phase**: v11b-1 complete
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